Mercurial > vim
annotate runtime/doc/vim9class.txt @ 34098:8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Commit: https://github.com/vim/vim/commit/b21499537fb9fd0ff407e6113ac60ebd82058e2a
Author: Aliaksei Budavei <32549825+zzzyxwvut@users.noreply.github.com>
Date: Sun Jan 7 17:52:10 2024 +0300
runtime(doc): Improve the documentation for Vim9 classes (https://github.com/vim/vim/issues/13828)
* Emend textual typos
* Emend syntactic errors in examples
* Acknowledge no support for abstract static methods
* Acknowledge the non-ubiquity of instance qualification
"This" was never allowed in method declarations, e.g.:
class A
def this.M()
enddef
endclass
and, since patch 9.0.2167, "this" can no longer be used in field
declarations, e.g.:
class B
var this.f: string
endclass
* Recognise abstract child classes
* Reword an ambiguous turn of phrase
Signed-off-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Sun, 07 Jan 2024 16:00:09 +0100 |
parents | 4635e43f2c6f |
children | 0f2632b04cde |
rev | line source |
---|---|
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
1 *vim9class.txt* For Vim version 9.1. Last change: 2024 Jan 06 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
2 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
3 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
4 VIM REFERENCE MANUAL by Bram Moolenaar |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
5 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
6 |
34011
62d771d915fe
runtime(doc): list of new/changed features in version9.txt
Christian Brabandt <cb@256bit.org>
parents:
34008
diff
changeset
|
7 Vim9 classes, objects, interfaces, types and enums. *vim9-class* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
8 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
9 1. Overview |Vim9-class-overview| |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
10 2. A simple class |Vim9-simple-class| |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
11 3. Class variables and methods |Vim9-class-member| |
31885 | 12 4. Using an abstract class |Vim9-abstract-class| |
13 5. Using an interface |Vim9-using-interface| | |
14 6. More class details |Vim9-class| | |
15 7. Type definition |Vim9-type| | |
16 8. Enum |Vim9-enum| | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
17 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
18 9. Rationale |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
19 10. To be done later |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
20 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
21 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
22 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
23 1. Overview *Vim9-class-overview* |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
24 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
25 The fancy term is "object-oriented programming". You can find lots of study |
31885 | 26 material on this subject. Here we document what |Vim9| script provides, |
27 assuming you know the basics already. Added are helpful hints about how to | |
33636
53416c49a7ab
patch 9.0.2059: outstanding exceptions may be skipped
Christian Brabandt <cb@256bit.org>
parents:
33490
diff
changeset
|
28 use this functionality effectively. Vim9 classes and objects cannot be used |
53416c49a7ab
patch 9.0.2059: outstanding exceptions may be skipped
Christian Brabandt <cb@256bit.org>
parents:
33490
diff
changeset
|
29 in legacy Vim scripts and legacy functions. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
30 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
31 The basic item is an object: |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
32 - An object stores state. It contains one or more variables that can each |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
33 have a value. |
31885 | 34 - An object provides functions that use and manipulate its state. These |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
35 functions are invoked "on the object", which is what sets it apart from the |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
36 traditional separation of data and code that manipulates the data. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
37 - An object has a well defined interface, with typed member variables and |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
38 methods. |
31885 | 39 - Objects are created from a class and all objects have the same interface. |
40 This does not change at runtime, it is not dynamic. | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
41 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
42 An object can only be created by a class. A class provides: |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
43 - A new() method, the constructor, which returns an object for the class. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
44 This method is invoked on the class name: MyClass.new(). |
31885 | 45 - State shared by all objects of the class: class variables (class members). |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
46 - A hierarchy of classes, with super-classes and sub-classes, inheritance. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
47 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
48 An interface is used to specify properties of an object: |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
49 - An object can declare several interfaces that it implements. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
50 - Different objects implementing the same interface can be used the same way. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
51 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
52 The class hierarchy allows for single inheritance. Otherwise interfaces are |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
53 to be used where needed. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
54 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
55 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
56 Class modeling ~ |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
57 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
58 You can model classes any way you like. Keep in mind what you are building, |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
59 don't try to model the real world. This can be confusing, especially because |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
60 teachers use real-world objects to explain class relations and you might think |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
61 your model should therefore reflect the real world. It doesn't! The model |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
62 should match your purpose. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
63 |
31885 | 64 Keep in mind that composition (an object contains other objects) is often |
65 better than inheritance (an object extends another object). Don't waste time | |
66 trying to find the optimal class model. Or waste time discussing whether a | |
67 square is a rectangle or that a rectangle is a square. It doesn't matter. | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
68 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
69 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
70 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
71 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
72 2. A simple class *Vim9-simple-class* |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
73 |
31885 | 74 Let's start with a simple example: a class that stores a text position (see |
75 below for how to do this more efficiently): > | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
76 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
77 class TextPosition |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
78 var lnum: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
79 var col: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
80 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
81 def new(lnum: number, col: number) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
82 this.lnum = lnum |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
83 this.col = col |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
84 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
85 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
86 def SetLnum(lnum: number) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
87 this.lnum = lnum |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
88 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
89 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
90 def SetCol(col: number) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
91 this.col = col |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
92 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
93 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
94 def SetPosition(lnum: number, col: number) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
95 this.lnum = lnum |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
96 this.col = col |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
97 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
98 endclass |
31430 | 99 < *object* *Object* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
100 You can create an object from this class with the new() method: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
101 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
102 var pos = TextPosition.new(1, 1) |
34008
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
103 < |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
104 The object variables "lnum" and "col" can be accessed directly: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
105 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
106 echo $'The text position is ({pos.lnum}, {pos.col})' |
34056
c1074a41895e
runtime(doc): add missing help tags
Christian Brabandt <cb@256bit.org>
parents:
34033
diff
changeset
|
107 < *E1317* *E1327* *:this* |
34008
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
108 If you have been using other object-oriented languages you will notice that in |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
109 Vim, within a class definition, the declared object members are consistently |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
110 referred to with the "this." prefix. This is different from languages like |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
111 Java and TypeScript. The naming convention makes the object members easy to |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
112 spot. Also, when a variable does not have the "this." prefix you know it is |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
113 not an object variable. |
34008
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
114 *E1411* |
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
115 From outside the class definition, access an object's methods and variables by |
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
116 using the object name followed by a dot following by the member: > |
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
117 |
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
118 pos.lnum |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
119 pos.SetCol(10) |
34008
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
120 < |
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
121 *E1405* *E1406* |
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
122 A class name cannot be used as an expression. A class name cannot be used in |
9fc35ba5feb7
runtime(doc): add some error codes to `:help vim9class` (#13747)
Christian Brabandt <cb@256bit.org>
parents:
33996
diff
changeset
|
123 the left-hand-side of an assignment. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
124 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
125 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
126 Object variable write access ~ |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
127 *read-only-variable* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
128 Now try to change an object variable directly: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
129 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
130 pos.lnum = 9 |
31885 | 131 < *E1335* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
132 This will give you an error! That is because by default object variables can |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
133 be read but not set. That's why the TextPosition class provides a method for |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
134 it: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
135 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
136 pos.SetLnum(9) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
137 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
138 Allowing to read but not set an object variable is the most common and safest |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
139 way. Most often there is no problem using a value, while setting a value may |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
140 have side effects that need to be taken care of. In this case, the SetLnum() |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
141 method could check if the line number is valid and either give an error or use |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
142 the closest valid value. |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
143 *:public* *public-variable* *E1331* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
144 If you don't care about side effects and want to allow the object variable to |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
145 be changed at any time, you can make it public: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
146 |
34033
cf39f47f26df
runtime(doc): correct the :public example (#13795)
Christian Brabandt <cb@256bit.org>
parents:
34025
diff
changeset
|
147 public var lnum: number |
cf39f47f26df
runtime(doc): correct the :public example (#13795)
Christian Brabandt <cb@256bit.org>
parents:
34025
diff
changeset
|
148 public var col: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
149 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
150 Now you don't need the SetLnum(), SetCol() and SetPosition() methods, setting |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
151 "pos.lnum" directly above will no longer give an error. |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
152 *E1326* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
153 If you try to set an object variable that doesn't exist you get an error: > |
31579 | 154 pos.other = 9 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
155 < E1326: Member not found on object "TextPosition": other ~ |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
156 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
157 *E1376* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
158 A object variable cannot be accessed using the class name. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
159 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
160 Protected variables ~ |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
161 *protected-variable* *E1332* *E1333* |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
162 On the other hand, if you do not want the object variables to be read directly |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
163 from outside the class or its sub-classes, you can make them protected. This |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
164 is done by prefixing an underscore to the name: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
165 |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
166 var _lnum: number |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
167 var _col: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
168 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
169 Now you need to provide methods to get the value of the protected variables. |
31885 | 170 These are commonly called getters. We recommend using a name that starts with |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
171 "Get": > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
172 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
173 def GetLnum(): number |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
174 return this._lnum |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
175 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
176 |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
177 def GetCol(): number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
178 return this._col |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
179 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
180 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
181 This example isn't very useful, the variables might as well have been public. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
182 It does become useful if you check the value. For example, restrict the line |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
183 number to the total number of lines: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
184 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
185 def GetLnum(): number |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
186 if this._lnum > this._lineCount |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
187 return this._lineCount |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
188 endif |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
189 return this._lnum |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
190 enddef |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
191 < |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
192 Protected methods ~ |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
193 *protected-method* *E1366* |
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
194 If you want object methods to be accessible only from other methods of the |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
195 same class and not used from outside the class, then you can make them |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
196 protected. This is done by prefixing the method name with an underscore: > |
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
197 |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
198 class SomeClass |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
199 def _Foo(): number |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
200 return 10 |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
201 enddef |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
202 def Bar(): number |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
203 return this._Foo() |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
204 enddef |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
205 endclass |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
206 < |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
207 Accessing a protected method outside the class will result in an error (using |
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
208 the above class): > |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
209 |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
210 var a = SomeClass.new() |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
211 a._Foo() |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
212 < |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
213 Simplifying the new() method ~ |
33383
5c12ca4dcd45
patch 9.0.1950: Vim9: error codes spread out
Christian Brabandt <cb@256bit.org>
parents:
33379
diff
changeset
|
214 *new()* *constructor* |
34025
385c61388fc3
runtime(doc): add help tag multiple-constructors. (#13772)
Christian Brabandt <cb@256bit.org>
parents:
34012
diff
changeset
|
215 See also |default-constructor| and |multiple-constructors|. |
385c61388fc3
runtime(doc): add help tag multiple-constructors. (#13772)
Christian Brabandt <cb@256bit.org>
parents:
34012
diff
changeset
|
216 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
217 Many constructors take values for the object variables. Thus you very often |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
218 see this pattern: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
219 |
31885 | 220 class SomeClass |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
221 var lnum: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
222 var col: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
223 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
224 def new(lnum: number, col: number) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
225 this.lnum = lnum |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
226 this.col = col |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
227 enddef |
31885 | 228 endclass |
33379
7c9124711f99
patch 9.0.1948: Vim9: object variable "this." should only be used in constructor
Christian Brabandt <cb@256bit.org>
parents:
33372
diff
changeset
|
229 < |
7c9124711f99
patch 9.0.1948: Vim9: object variable "this." should only be used in constructor
Christian Brabandt <cb@256bit.org>
parents:
33372
diff
changeset
|
230 *E1390* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
231 Not only is this text you need to write, it also has the type of each |
33945
27746ed6cb05
runtime(doc): grammar & typo fixes
Christian Brabandt <cb@256bit.org>
parents:
33942
diff
changeset
|
232 variable twice. Since this is so common a shorter way to write new() is |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
233 provided: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
234 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
235 def new(this.lnum, this.col) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
236 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
237 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
238 The semantics are easy to understand: Providing the object variable name, |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
239 including "this.", as the argument to new() means the value provided in the |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
240 new() call is assigned to that object variable. This mechanism comes from the |
31885 | 241 Dart language. |
242 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
243 Putting together this way of using new() and making the variables public |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
244 results in a much shorter class definition than what we started with: > |
31885 | 245 |
246 class TextPosition | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
247 public var lnum: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
248 public var col: number |
31885 | 249 |
250 def new(this.lnum, this.col) | |
251 enddef | |
252 | |
253 def SetPosition(lnum: number, col: number) | |
254 this.lnum = lnum | |
255 this.col = col | |
256 enddef | |
257 endclass | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
258 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
259 The sequence of constructing a new object is: |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
260 1. Memory is allocated and cleared. All values are zero/false/empty. |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
261 2. For each declared object variable that has an initializer, the expression |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
262 is evaluated and assigned to the variable. This happens in the sequence |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
263 the variables are declared in the class. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
264 3. Arguments in the new() method in the "this.name" form are assigned. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
265 4. The body of the new() method is executed. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
266 |
31885 | 267 If the class extends a parent class, the same thing happens. In the second |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
268 step the object variables of the parent class are initialized first. There is |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
269 no need to call "super()" or "new()" on the parent. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
270 |
33385
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
271 *E1365* |
32903
54c01bb98b8e
patch 9.0.1760: vim9 class problem with new() constructor
Christian Brabandt <cb@256bit.org>
parents:
32294
diff
changeset
|
272 When defining the new() method the return type should not be specified. It |
54c01bb98b8e
patch 9.0.1760: vim9 class problem with new() constructor
Christian Brabandt <cb@256bit.org>
parents:
32294
diff
changeset
|
273 always returns an object of the class. |
54c01bb98b8e
patch 9.0.1760: vim9 class problem with new() constructor
Christian Brabandt <cb@256bit.org>
parents:
32294
diff
changeset
|
274 |
33385
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
275 *E1386* |
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
276 When invoking an object method, the method name should be preceded by the |
33945
27746ed6cb05
runtime(doc): grammar & typo fixes
Christian Brabandt <cb@256bit.org>
parents:
33942
diff
changeset
|
277 object variable name. An object method cannot be invoked using the class |
33385
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
278 name. |
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
279 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
280 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
281 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
282 3. Class Variables and Methods *Vim9-class-member* |
31885 | 283 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
284 *:static* *E1337* *E1338* *E1368* |
31885 | 285 Class members are declared with "static". They are used by the name without a |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
286 prefix in the class where they are defined: > |
31885 | 287 |
288 class OtherThing | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
289 var size: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
290 static var totalSize: number |
31885 | 291 |
292 def new(this.size) | |
293 totalSize += this.size | |
294 enddef | |
295 endclass | |
296 < *E1340* *E1341* | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
297 Since the name is used as-is, shadowing the name by a method argument name |
31885 | 298 or local variable name is not allowed. |
299 | |
33385
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
300 *E1374* *E1375* *E1384* *E1385* |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
301 To access a class member outside of the class where it is defined, the class |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
302 name prefix must be used. A class member cannot be accessed using an object. |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
303 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
304 Just like object members the access can be made protected by using an |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
305 underscore as the first character in the name, and it can be made public by |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
306 prefixing "public": > |
31885 | 307 |
308 class OtherThing | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
309 static var total: number # anybody can read, only class can write |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
310 static var _sum: number # only class can read and write |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
311 public static var result: number # anybody can read and write |
31885 | 312 endclass |
313 < | |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
314 *class-method* |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
315 Class methods are also declared with "static". They can use the class |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
316 variables but they have no access to the object variables, they cannot use the |
33434
484543479bd7
runtime(doc): fix typos.
Christian Brabandt <cb@256bit.org>
parents:
33432
diff
changeset
|
317 "this" keyword: |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
318 > |
31885 | 319 class OtherThing |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
320 var size: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
321 static var totalSize: number |
31885 | 322 |
323 # Clear the total size and return the value it had before. | |
324 static def ClearTotalSize(): number | |
325 var prev = totalSize | |
326 totalSize = 0 | |
327 return prev | |
328 enddef | |
329 endclass | |
330 | |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
331 Inside the class the class method can be called by name directly, outside the |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
332 class the class name must be prefixed: `OtherThing.ClearTotalSize()`. To use |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
333 a class method from a parent class in a child class, the class name must be |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
334 prefixed. |
31885 | 335 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
336 Just like object methods the access can be made protected by using an |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
337 underscore as the first character in the method name: > |
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
338 |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
339 class OtherThing |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
340 static def _Foo() |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
341 echo "Foo" |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
342 enddef |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
343 def Bar() |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
344 _Foo() |
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
345 enddef |
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
346 endclass |
33068
d42927c6e556
patch 9.0.1821: Vim9 constructors are always static
Christian Brabandt <cb@256bit.org>
parents:
33025
diff
changeset
|
347 < |
d42927c6e556
patch 9.0.1821: Vim9 constructors are always static
Christian Brabandt <cb@256bit.org>
parents:
33025
diff
changeset
|
348 *E1370* |
34012
291b4ea552eb
runtime(doc): Clarify that new() is not static
Christian Brabandt <cb@256bit.org>
parents:
34011
diff
changeset
|
349 Note that constructors cannot be declared as "static". They are called like a |
291b4ea552eb
runtime(doc): Clarify that new() is not static
Christian Brabandt <cb@256bit.org>
parents:
34011
diff
changeset
|
350 static but execute as an object method; they have access to "this". |
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
351 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
352 To access the class methods and class variables of a super class in an |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
353 extended class, the class name prefix should be used just as from anywhere |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
354 outside of the defining class: > |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
355 |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
356 vim9script |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
357 class Vehicle |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
358 static var nextID: number = 1000 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
359 static def GetID(): number |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
360 nextID += 1 |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
361 return nextID |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
362 enddef |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
363 endclass |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
364 class Car extends Vehicle |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
365 var myID: number |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
366 def new() |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
367 this.myID = Vehicle.GetID() |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
368 enddef |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
369 endclass |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
370 < |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
371 Class variables and methods are not inherited by a child class. A child class |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
372 can declare a static variable or a method with the same name as the one in the |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
373 super class. Depending on the class where the member is used the |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
374 corresponding class member will be used. The type of the class member in a |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
375 child class can be different from that in the super class. |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
376 |
33996
6d33f47b71b8
patch 9.0.2182: Vim9: need a way to reserve future extension
Christian Brabandt <cb@256bit.org>
parents:
33951
diff
changeset
|
377 The double underscore (__) prefix for a class or object method name is |
6d33f47b71b8
patch 9.0.2182: Vim9: need a way to reserve future extension
Christian Brabandt <cb@256bit.org>
parents:
33951
diff
changeset
|
378 reserved for future use. |
6d33f47b71b8
patch 9.0.2182: Vim9: need a way to reserve future extension
Christian Brabandt <cb@256bit.org>
parents:
33951
diff
changeset
|
379 |
33951
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
380 *object-final-variable* *E1409* |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
381 The |:final| keyword can be used to make a class or object variable a |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
382 constant. Examples: > |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
383 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
384 class A |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
385 final v1 = [1, 2] # final object variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
386 public final v2 = {x: 1} # final object variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
387 static final v3 = 'abc' # final class variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
388 public static final v4 = 0z10 # final class variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
389 endclass |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
390 < |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
391 A final variable can be changed only from a constructor function. Example: > |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
392 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
393 class A |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
394 final v1: list<number> |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
395 def new() |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
396 this.v1 = [1, 2] |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
397 enddef |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
398 endclass |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
399 var a = A.new() |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
400 echo a.v1 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
401 < |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
402 Note that the value of a final variable can be changed. Example: > |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
403 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
404 class A |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
405 public final v1 = [1, 2] |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
406 endclass |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
407 var a = A.new() |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
408 a.v1[0] = 6 # OK |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
409 a.v1->add(3) # OK |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
410 a.v1 = [3, 4] # Error |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
411 < |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
412 *E1408* |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
413 Final variables are not supported in an interface. A class or object method |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
414 cannot be final. |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
415 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
416 *object-const-variable* |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
417 The |:const| keyword can be used to make a class or object variable and the |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
418 value a constant. Examples: > |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
419 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
420 class A |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
421 const v1 = [1, 2] # const object variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
422 public const v2 = {x: 1} # const object variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
423 static const v3 = 'abc' # const class variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
424 public static const v4 = 0z10 # const class variable |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
425 endclass |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
426 < |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
427 A const variable can be changed only from a constructor function. Example: > |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
428 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
429 class A |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
430 const v1: list<number> |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
431 def new() |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
432 this.v1 = [1, 2] |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
433 enddef |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
434 endclass |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
435 var a = A.new() |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
436 echo a.v1 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
437 < |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
438 A const variable and its value cannot be changed. Example: > |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
439 |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
440 class A |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
441 public const v1 = [1, 2] |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
442 endclass |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
443 var a = A.new() |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
444 a.v1[0] = 6 # Error |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
445 a.v1->add(3) # Error |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
446 a.v1 = [3, 4] # Error |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
447 < |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
448 *E1410* |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
449 Const variables are not supported in an interface. A class or object method |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
450 cannot be a const. |
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
451 |
31885 | 452 ============================================================================== |
453 | |
454 4. Using an abstract class *Vim9-abstract-class* | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
455 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
456 An abstract class forms the base for at least one sub-class. In the class |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
457 model one often finds that a few classes have the same properties that can be |
31885 | 458 shared, but a class with these properties does not have enough state to create |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
459 an object from. A sub-class must extend the abstract class and add the |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
460 missing state and/or methods before it can be used to create objects for. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
461 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
462 For example, a Shape class could store a color and thickness. You cannot |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
463 create a Shape object, it is missing the information about what kind of shape |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
464 it is. The Shape class functions as the base for a Square and a Triangle |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
465 class, for which objects can be created. Example: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
466 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
467 abstract class Shape |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
468 var color = Color.Black |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
469 var thickness = 10 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
470 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
471 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
472 class Square extends Shape |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
473 var size: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
474 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
475 def new(this.size) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
476 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
477 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
478 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
479 class Triangle extends Shape |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
480 var base: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
481 var height: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
482 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
483 def new(this.base, this.height) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
484 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
485 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
486 < |
31885 | 487 An abstract class is defined the same way as a normal class, except that it |
488 does not have any new() method. *E1359* | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
489 |
33798
af1b18018eeb
runtime(doc): Fix whitespace and formatting of some help files (#13549)
Christian Brabandt <cb@256bit.org>
parents:
33738
diff
changeset
|
490 *abstract-method* *E1371* *E1372* |
33217
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
491 An abstract method can be defined in an abstract class by using the "abstract" |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
492 prefix when defining the method: > |
33217
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
493 |
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
494 abstract class Shape |
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
495 abstract def Draw() |
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
496 endclass |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
497 < |
33698
643db54ed3e7
patch 9.0.2084: Vim9: abstract static methods are possible
Christian Brabandt <cb@256bit.org>
parents:
33682
diff
changeset
|
498 A static method in an abstract class cannot be an abstract method. |
643db54ed3e7
patch 9.0.2084: Vim9: abstract static methods are possible
Christian Brabandt <cb@256bit.org>
parents:
33682
diff
changeset
|
499 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
500 *E1373* |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
501 A non-abstract class extending the abstract class must implement all the |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
502 abstract methods. The signature (arguments, argument types and return type) |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
503 must be exactly the same. If the return type of a method is a class, then |
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
504 that class or one of its subclasses can be used in the extended method. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
505 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
506 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
507 |
31885 | 508 5. Using an interface *Vim9-using-interface* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
509 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
510 The example above with Shape, Square and Triangle can be made more useful if |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
511 we add a method to compute the surface of the object. For that we create the |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
512 interface called HasSurface, which specifies one method Surface() that returns |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
513 a number. This example extends the one above: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
514 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
515 abstract class Shape |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
516 var color = Color.Black |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
517 var thickness = 10 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
518 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
519 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
520 interface HasSurface |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
521 def Surface(): number |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
522 endinterface |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
523 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
524 class Square extends Shape implements HasSurface |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
525 var size: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
526 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
527 def new(this.size) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
528 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
529 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
530 def Surface(): number |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
531 return this.size * this.size |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
532 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
533 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
534 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
535 class Triangle extends Shape implements HasSurface |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
536 var base: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
537 var height: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
538 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
539 def new(this.base, this.height) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
540 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
541 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
542 def Surface(): number |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
543 return this.base * this.height / 2 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
544 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
545 endclass |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
546 < |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
547 *E1348* *E1349* *E1367* *E1382* *E1383* |
31671 | 548 If a class declares to implement an interface, all the items specified in the |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
549 interface must appear in the class, with the same types. |
31671 | 550 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
551 The interface name can be used as a type: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
552 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
553 var shapes: list<HasSurface> = [ |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
554 Square.new(12), |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
555 Triangle.new(8, 15), |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
556 ] |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
557 for shape in shapes |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
558 echo $'the surface is {shape.Surface()}' |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
559 endfor |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
560 < |
33372
3e9a91624b40
patch 9.0.1945: Vim9: missing support for ro-vars in interface
Christian Brabandt <cb@256bit.org>
parents:
33351
diff
changeset
|
561 *E1378* *E1379* *E1380* *E1387* |
3e9a91624b40
patch 9.0.1945: Vim9: missing support for ro-vars in interface
Christian Brabandt <cb@256bit.org>
parents:
33351
diff
changeset
|
562 An interface can contain only object methods and read-only object variables. |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
563 An interface cannot contain read-write or protected object variables, |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
564 protected object methods, class variables and class methods. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
565 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
566 An interface can extend another interface using "extends". The sub-interface |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
567 inherits all the instance variables and methods from the super interface. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
568 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
569 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
570 |
31885 | 571 6. More class details *Vim9-class* *Class* *class* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
572 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
573 Defining a class ~ |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
574 *:class* *:endclass* *:abstract* |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
575 A class is defined between `:class` and `:endclass`. The whole class is |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
576 defined in one script file. It is not possible to add to a class later. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
577 |
31430 | 578 A class can only be defined in a |Vim9| script file. *E1316* |
31396
307f68a41b03
patch 9.0.1031: Vim9 class is not implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
31335
diff
changeset
|
579 A class cannot be defined inside a function. |
307f68a41b03
patch 9.0.1031: Vim9 class is not implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
31335
diff
changeset
|
580 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
581 It is possible to define more than one class in a script file. Although it |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
582 usually is better to export only one main class. It can be useful to define |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
583 types, enums and helper classes though. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
584 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
585 The `:abstract` keyword may be prefixed and `:export` may be used. That gives |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
586 these variants: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
587 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
588 class ClassName |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
589 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
590 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
591 export class ClassName |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
592 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
593 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
594 abstract class ClassName |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
595 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
596 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
597 export abstract class ClassName |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
598 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
599 < |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
600 *E1314* |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
601 The class name should be CamelCased. It must start with an uppercase letter. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
602 That avoids clashing with builtin types. |
31430 | 603 *E1315* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
604 After the class name these optional items can be used. Each can appear only |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
605 once. They can appear in any order, although this order is recommended: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
606 extends ClassName |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
607 implements InterfaceName, OtherInterface |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
608 specifies SomeInterface |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
609 < *E1355* *E1369* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
610 Each variable and method name can be used only once. It is not possible to |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
611 define a method with the same name and different type of arguments. It is not |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
612 possible to use a public and protected member variable with the same name. An |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
613 object variable name used in a super class cannot be reused in a child class. |
31885 | 614 |
615 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
616 Object Variable Initialization ~ |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
617 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
618 If the type of a variable is not explicitly specified in a class, then it is |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
619 set to "any" during class definition. When an object is instantiated from the |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
620 class, then the type of the variable is set. |
32960
d5c05e15cf81
patch 9.0.1780: Vim9 type not defined during object creation
Christian Brabandt <cb@256bit.org>
parents:
32903
diff
changeset
|
621 |
33401
bb99820510ef
patch 9.0.1959: Vim9: methods parameters and types are covariant
Christian Brabandt <cb@256bit.org>
parents:
33385
diff
changeset
|
622 The following reserved keyword names cannot be used as an object or class |
bb99820510ef
patch 9.0.1959: Vim9: methods parameters and types are covariant
Christian Brabandt <cb@256bit.org>
parents:
33385
diff
changeset
|
623 variable name: "super", "this", "true", "false", "null", "null_blob", |
bb99820510ef
patch 9.0.1959: Vim9: methods parameters and types are covariant
Christian Brabandt <cb@256bit.org>
parents:
33385
diff
changeset
|
624 "null_dict", "null_function", "null_list", "null_partial", "null_string", |
bb99820510ef
patch 9.0.1959: Vim9: methods parameters and types are covariant
Christian Brabandt <cb@256bit.org>
parents:
33385
diff
changeset
|
625 "null_channel" and "null_job". |
32960
d5c05e15cf81
patch 9.0.1780: Vim9 type not defined during object creation
Christian Brabandt <cb@256bit.org>
parents:
32903
diff
changeset
|
626 |
31885 | 627 Extending a class ~ |
628 *extends* | |
31671 | 629 A class can extend one other class. *E1352* *E1353* *E1354* |
31885 | 630 The basic idea is to build on top of an existing class, add properties to it. |
631 | |
632 The extended class is called the "base class" or "super class". The new class | |
633 is called the "child class". | |
634 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
635 Object variables from the base class are all taken over by the child class. It |
31885 | 636 is not possible to override them (unlike some other languages). |
637 | |
638 *E1356* *E1357* *E1358* | |
33432
97ceabebaeaf
patch 9.0.1974: vim9: using contra-variant type-checks
Christian Brabandt <cb@256bit.org>
parents:
33401
diff
changeset
|
639 Object methods of the base class can be overruled. The signature (arguments, |
33490
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
640 argument types and return type) must be exactly the same. If the return type |
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
641 of a method is a class, then that class or one of its subclasses can be used |
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
642 in the extended method. The method of the base class can be called by |
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
643 prefixing "super.". |
31885 | 644 |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
645 *E1377* |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
646 The access level of a method (public or protected) in a child class should be |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
647 the same as the super class. |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
648 |
31885 | 649 Other object methods of the base class are taken over by the child class. |
650 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
651 Class methods, including methods starting with "new", can be overruled, like |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
652 with object methods. The method on the base class can be called by prefixing |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
653 the name of the class (for class methods) or "super.". |
31885 | 654 |
655 Unlike other languages, the constructor of the base class does not need to be | |
656 invoked. In fact, it cannot be invoked. If some initialization from the base | |
657 class also needs to be done in a child class, put it in an object method and | |
658 call that method from every constructor(). | |
659 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
660 If the base class did not specify a new() method then one was automatically |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
661 created. This method will not be taken over by the child class. The child |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
662 class can define its own new() method, or, if there isn't one, a new() method |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
663 will be added automatically. |
31885 | 664 |
665 | |
666 A class implementing an interface ~ | |
33372
3e9a91624b40
patch 9.0.1945: Vim9: missing support for ro-vars in interface
Christian Brabandt <cb@256bit.org>
parents:
33351
diff
changeset
|
667 *implements* *E1346* *E1347* *E1389* |
31671 | 668 A class can implement one or more interfaces. The "implements" keyword can |
669 only appear once *E1350* . Multiple interfaces can be specified, separated by | |
670 commas. Each interface name can appear only once. *E1351* | |
31885 | 671 |
672 | |
673 A class defining an interface ~ | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
674 *specifies* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
675 A class can declare its interface, the object variables and methods, with a |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
676 named interface. This avoids the need for separately specifying the |
31396
307f68a41b03
patch 9.0.1031: Vim9 class is not implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
31335
diff
changeset
|
677 interface, which is often done in many languages, especially Java. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
678 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
679 |
31430 | 680 Items in a class ~ |
33372
3e9a91624b40
patch 9.0.1945: Vim9: missing support for ro-vars in interface
Christian Brabandt <cb@256bit.org>
parents:
33351
diff
changeset
|
681 *E1318* *E1325* *E1388* |
32061 | 682 Inside a class, in between `:class` and `:endclass`, these items can appear: |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
683 - An object variable declaration: > |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
684 var _protectedVariableName: memberType |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
685 var readonlyVariableName: memberType |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
686 public var readwriteVariableName: memberType |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
687 - A class variable declaration: > |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
688 static var _protectedClassVariableName: memberType |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
689 static var readonlyClassVariableName: memberType |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
690 public static var readwriteClassVariableName: memberType |
31430 | 691 - A constructor method: > |
32004 | 692 def new(arguments) |
693 def newName(arguments) | |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
694 - A class method: > |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
695 static def SomeMethod(arguments) |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
696 static def _ProtectedMethod(arguments) |
31430 | 697 - An object method: > |
32004 | 698 def SomeMethod(arguments) |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
699 def _ProtectedMethod(arguments) |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
700 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
701 For the object variable the type must be specified. The best way is to do |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
702 this explicitly with ": {type}". For simple types you can also use an |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
703 initializer, such as "= 123", and Vim will see that the type is a number. |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
704 Avoid doing this for more complex types and when the type will be incomplete. |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
705 For example: > |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
706 var nameList = [] |
31579 | 707 This specifies a list, but the item type is unknown. Better use: > |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
708 var nameList: list<string> |
31579 | 709 The initialization isn't needed, the list is empty by default. |
710 *E1330* | |
711 Some types cannot be used, such as "void", "null" and "v:none". | |
31430 | 712 |
713 | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
714 Defining an interface ~ |
34056
c1074a41895e
runtime(doc): add missing help tags
Christian Brabandt <cb@256bit.org>
parents:
34033
diff
changeset
|
715 *Interface* *:interface* *:endinterface* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
716 An interface is defined between `:interface` and `:endinterface`. It may be |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
717 prefixed with `:export`: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
718 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
719 interface InterfaceName |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
720 endinterface |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
721 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
722 export interface InterfaceName |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
723 endinterface |
31671 | 724 < *E1344* |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
725 An interface can declare object variables, just like in a class but without |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
726 any initializer. |
31671 | 727 *E1345* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
728 An interface can declare methods with `:def`, including the arguments and |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
729 return type, but without the body and without `:enddef`. Example: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
730 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
731 interface HasSurface |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
732 var size: number |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
733 def Surface(): number |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
734 endinterface |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
735 |
31671 | 736 An interface name must start with an uppercase letter. *E1343* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
737 The "Has" prefix can be used to make it easier to guess this is an interface |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
738 name, with a hint about what it provides. |
31671 | 739 An interface can only be defined in a |Vim9| script file. *E1342* |
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
740 An interface cannot "implement" another interface but it can "extend" another |
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
741 interface. *E1381* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
742 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
743 |
32004 | 744 null object ~ |
745 | |
32061 | 746 When a variable is declared to have the type of an object, but it is not |
32004 | 747 initialized, the value is null. When trying to use this null object Vim often |
748 does not know what class was supposed to be used. Vim then cannot check if | |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
749 a variable name is correct and you will get a "Using a null object" error, |
33434
484543479bd7
runtime(doc): fix typos.
Christian Brabandt <cb@256bit.org>
parents:
33432
diff
changeset
|
750 even when the variable name is invalid. *E1360* *E1362* |
32004 | 751 |
752 | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
753 Default constructor ~ |
33383
5c12ca4dcd45
patch 9.0.1950: Vim9: error codes spread out
Christian Brabandt <cb@256bit.org>
parents:
33379
diff
changeset
|
754 *default-constructor* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
755 In case you define a class without a new() method, one will be automatically |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
756 defined. This default constructor will have arguments for all the object |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
757 variables, in the order they were specified. Thus if your class looks like: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
758 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
759 class AutoNew |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
760 var name: string |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
761 var age: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
762 var gender: Gender |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
763 endclass |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
764 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
765 Then the default constructor will be: > |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
766 |
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
767 def new(this.name = v:none, this.age = v:none, this.gender = v:none) |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
768 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
769 |
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
770 The "= v:none" default values make the arguments optional. Thus you can also |
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
771 call `new()` without any arguments. No assignment will happen and the default |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
772 value for the object variables will be used. This is a more useful example, |
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
773 with default values: > |
31430 | 774 |
775 class TextPosition | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
776 var lnum: number = 1 |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
777 var col: number = 1 |
31430 | 778 endclass |
779 | |
780 If you want the constructor to have mandatory arguments, you need to write it | |
781 yourself. For example, if for the AutoNew class above you insist on getting | |
782 the name, you can define the constructor like this: > | |
783 | |
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
784 def new(this.name, this.age = v:none, this.gender = v:none) |
31430 | 785 enddef |
33891
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
786 < |
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
787 When using the default new() method, if the order of the object variables in |
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
788 the class is changed later, then all the callers of the default new() method |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
789 need to change. To avoid this, the new() method can be explicitly defined |
33891
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
790 without any arguments. |
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
791 |
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
792 *E1328* |
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
793 Note that you cannot use another default value than "v:none" here. If you |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
794 want to initialize the object variables, do it where they are declared. This |
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
795 way you only need to look in one place for the default values. |
31430 | 796 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
797 All object variables will be used in the default constructor, including |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
798 protected access ones. |
31671 | 799 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
800 If the class extends another one, the object variables of that class will come |
31671 | 801 first. |
802 | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
803 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
804 Multiple constructors ~ |
34025
385c61388fc3
runtime(doc): add help tag multiple-constructors. (#13772)
Christian Brabandt <cb@256bit.org>
parents:
34012
diff
changeset
|
805 *multiple-constructors* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
806 Normally a class has just one new() constructor. In case you find that the |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
807 constructor is often called with the same arguments you may want to simplify |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
808 your code by putting those arguments into a second constructor method. For |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
809 example, if you tend to use the color black a lot: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
810 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
811 def new(this.garment, this.color, this.size) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
812 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
813 ... |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
814 var pants = new(Garment.pants, Color.black, "XL") |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
815 var shirt = new(Garment.shirt, Color.black, "XL") |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
816 var shoes = new(Garment.shoes, Color.black, "45") |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
817 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
818 Instead of repeating the color every time you can add a constructor that |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
819 includes it: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
820 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
821 def newBlack(this.garment, this.size) |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
822 this.color = Color.black |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
823 enddef |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
824 ... |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
825 var pants = newBlack(Garment.pants, "XL") |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
826 var shirt = newBlack(Garment.shirt, "XL") |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
827 var shoes = newBlack(Garment.shoes, "9.5") |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
828 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
829 Note that the method name must start with "new". If there is no method called |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
830 "new()" then the default constructor is added, even though there are other |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
831 constructor methods. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
832 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
833 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
834 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
835 |
34056
c1074a41895e
runtime(doc): add missing help tags
Christian Brabandt <cb@256bit.org>
parents:
34033
diff
changeset
|
836 7. Type definition *typealias* *Vim9-type* *:type* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
837 |
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
838 *E1393* *E1395* *E1396* *E1397* *E1398* |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
839 A type definition is giving a name to a type specification. This is also |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
840 known as a "type alias". The type alias can be used wherever a built-in type |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
841 can be used. Example: > |
33490
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
842 |
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
843 type ListOfStrings = list<string> |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
844 var s: ListOfStrings = ['a', 'b'] |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
845 |
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
846 def ProcessStr(str: ListOfStrings): ListOfStrings |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
847 return str |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
848 enddef |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
849 echo ProcessStr(s) |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
850 < |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
851 *E1394* |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
852 A type alias name must start with an upper case character. Only existing |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
853 types can be aliased. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
854 |
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
855 *E1399* |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
856 A type alias can be created only at the script level and not inside a |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
857 function. A type alias can be exported and used across scripts. |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
858 |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
859 *E1400* *E1401* *E1402* *E1403* *E1407* |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
860 A type alias cannot be used as an expression. A type alias cannot be used in |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
861 the left-hand-side of an assignment. |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
862 |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
863 For a type alias name, the |typename()| function returns the type that is |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
864 aliased: > |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
865 |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
866 type ListOfStudents = list<dict<any>> |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
867 echo typename(ListOfStudents) |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
868 typealias<list<dict<any>>> |
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
869 < |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
870 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
871 |
31885 | 872 8. Enum *Vim9-enum* *:enum* *:endenum* |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
873 |
33490
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
874 {not implemented yet} |
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
875 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
876 An enum is a type that can have one of a list of values. Example: > |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
877 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
878 :enum Color |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
879 White |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
880 Red |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
881 Green |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
882 Blue |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
883 Black |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
884 :endenum |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
885 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
886 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
887 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
888 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
889 9. Rationale |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
890 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
891 Most of the choices for |Vim9| classes come from popular and recently |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
892 developed languages, such as Java, TypeScript and Dart. The syntax has been |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
893 made to fit with the way Vim script works, such as using `endclass` instead of |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
894 using curly braces around the whole class. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
895 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
896 Some common constructs of object-oriented languages were chosen very long ago |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
897 when this kind of programming was still new, and later found to be |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
898 sub-optimal. By this time those constructs were widely used and changing them |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
899 was not an option. In Vim we do have the freedom to make different choices, |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
900 since classes are completely new. We can make the syntax simpler and more |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
901 consistent than what "old" languages use. Without diverting too much, it |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
902 should still mostly look like what you know from existing languages. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
903 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
904 Some recently developed languages add all kinds of fancy features that we |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
905 don't need for Vim. But some have nice ideas that we do want to use. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
906 Thus we end up with a base of what is common in popular languages, dropping |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
907 what looks like a bad idea, and adding some nice features that are easy to |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
908 understand. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
909 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
910 The main rules we use to make decisions: |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
911 - Keep it simple. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
912 - No surprises, mostly do what other languages are doing. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
913 - Avoid mistakes from the past. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
914 - Avoid the need for the script writer to consult the help to understand how |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
915 things work, most things should be obvious. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
916 - Keep it consistent. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
917 - Aim at an average size plugin, not at a huge project. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
918 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
919 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
920 Using new() for the constructor ~ |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
921 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
922 Many languages use the class name for the constructor method. A disadvantage |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
923 is that quite often this is a long name. And when changing the class name all |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
924 constructor methods need to be renamed. Not a big deal, but still a |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
925 disadvantage. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
926 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
927 Other languages, such as TypeScript, use a specific name, such as |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
928 "constructor()". That seems better. However, using "new" or "new()" to |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
929 create a new object has no obvious relation with "constructor()". |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
930 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
931 For |Vim9| script using the same method name for all constructors seemed like |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
932 the right choice, and by calling it new() the relation between the caller and |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
933 the method being called is obvious. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
934 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
935 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
936 No overloading of the constructor ~ |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
937 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
938 In Vim script, both legacy and |Vim9| script, there is no overloading of |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
939 methods. That means it is not possible to use the same method name with |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
940 different types of arguments. Therefore there also is only one new() |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
941 constructor. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
942 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
943 With |Vim9| script it would be possible to support overloading, since |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
944 arguments are typed. However, this gets complicated very quickly. Looking at |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
945 a new() call one has to inspect the types of the arguments to know which of |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
946 several new() methods is actually being called. And that can require |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
947 inspecting quite a bit of code. For example, if one of the arguments is the |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
948 return value of a method, you need to find that method to see what type it is |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
949 returning. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
950 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
951 Instead, every constructor has to have a different name, starting with "new". |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
952 That way multiple constructors with different arguments are possible, while it |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
953 is very easy to see which constructor is being used. And the type of |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
954 arguments can be properly checked. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
955 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
956 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
957 No overloading of methods ~ |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
958 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
959 Same reasoning as for the constructor: It is often not obvious what type |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
960 arguments have, which would make it difficult to figure out what method is |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
961 actually being called. Better just give the methods a different name, then |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
962 type checking will make sure it works as you intended. This rules out |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
963 polymorphism, which we don't really need anyway. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
964 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
965 |
31671 | 966 Single inheritance and interfaces ~ |
967 | |
968 Some languages support multiple inheritance. Although that can be useful in | |
969 some cases, it makes the rules of how a class works quite complicated. | |
970 Instead, using interfaces to declare what is supported is much simpler. The | |
971 very popular Java language does it this way, and it should be good enough for | |
31885 | 972 Vim. The "keep it simple" rule applies here. |
31671 | 973 |
974 Explicitly declaring that a class supports an interface makes it easy to see | |
975 what a class is intended for. It also makes it possible to do proper type | |
976 checking. When an interface is changed any class that declares to implement | |
977 it will be checked if that change was also changed. The mechanism to assume a | |
978 class implements an interface just because the methods happen to match is | |
979 brittle and leads to obscure problems, let's not do that. | |
980 | |
981 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
982 Using "this.variable" everywhere ~ |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
983 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
984 The object variables in various programming languages can often be accessed in |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
985 different ways, depending on the location. Sometimes "this." has to be |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
986 prepended to avoid ambiguity. They are usually declared without "this.". |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
987 That is quite inconsistent and sometimes confusing. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
988 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
989 A very common issue is that in the constructor the arguments use the same name |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
990 as the object variable. Then for these variables "this." needs to be prefixed |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
991 in the body, while for other variables this is not needed and often omitted. |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
992 This leads to a mix of variables with and without "this.", which is |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
993 inconsistent. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
994 |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
995 For |Vim9| classes the "this." prefix is always used for declared methods and |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
996 variables. Simple and consistent. When looking at the code inside a class |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
997 it's also directly clear which variable references are object variables and |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
998 which aren't. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
999 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1000 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1001 Using class variables ~ |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1002 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1003 Using "static variable" to declare a class variable is very common, nothing |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1004 new here. In |Vim9| script these can be accessed directly by their name. |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1005 Very much like how a script-local variable can be used in a method. Since |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1006 object variables are always accessed with "this." prepended, it's also quickly |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1007 clear what kind of variable it is. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1008 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1009 TypeScript prepends the class name before the class variable name, also inside |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1010 the class. This has two problems: The class name can be rather long, taking |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1011 up quite a bit of space, and when the class is renamed all these places need |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1012 to be changed too. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1013 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1014 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1015 Declaring object and class variables ~ |
31671 | 1016 |
1017 The main choice is whether to use "var" as with variable declarations. | |
1018 TypeScript does not use it: > | |
1019 class Point { | |
1020 x: number; | |
1021 y = 0; | |
1022 } | |
1023 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1024 Following that Vim object variables could be declared like this: > |
31671 | 1025 class Point |
1026 this.x: number | |
1027 this.y = 0 | |
1028 endclass | |
1029 | |
1030 Some users pointed out that this looks more like an assignment than a | |
34098
8241df3e6dc1
runtime(doc): Improve the documentation for Vim9 classes (#13828)
Christian Brabandt <cb@256bit.org>
parents:
34057
diff
changeset
|
1031 declaration. Adding "var" and omitting "this." changes that: > |
31671 | 1032 class Point |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1033 var x: number |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1034 var y = 0 |
31671 | 1035 endclass |
1036 | |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1037 We also need to be able to declare class variables using the "static" keyword. |
31671 | 1038 There we can also choose to leave out "var": > |
1039 class Point | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1040 var x: number |
31671 | 1041 static count = 0 |
1042 endclass | |
1043 | |
1044 Or do use it, before "static": > | |
1045 class Point | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1046 var x: number |
31671 | 1047 var static count = 0 |
1048 endclass | |
1049 | |
1050 Or after "static": > | |
1051 class Point | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1052 var x: number |
31671 | 1053 static var count = 0 |
1054 endclass | |
1055 | |
1056 This is more in line with "static def Func()". | |
1057 | |
1058 There is no clear preference whether to use "var" or not. The two main | |
1059 reasons to leave it out are: | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1060 1. TypeScript and other popular languages do not use it. |
31671 | 1061 2. Less clutter. |
1062 | |
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1063 However, it is more common for languages to reuse their general variable and |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1064 function declaration syntax for class/object variables and methods. Vim9 also |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1065 reuses the general function declaration syntax for methods. So, for the sake |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1066 of consistency, we require "var" in these declarations. |
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1067 |
31671 | 1068 |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1069 Using "ClassName.new()" to construct an object ~ |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1070 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1071 Many languages use the "new" operator to create an object, which is actually |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1072 kind of strange, since the constructor is defined as a method with arguments, |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1073 not a command. TypeScript also has the "new" keyword, but the method is |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1074 called "constructor()", it is hard to see the relation between the two. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1075 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1076 In |Vim9| script the constructor method is called new(), and it is invoked as |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1077 new(), simple and straightforward. Other languages use "new ClassName()", |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1078 while there is no ClassName() method, it's a method by another name in the |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1079 class called ClassName. Quite confusing. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1080 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1081 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1082 Vim9class access modes ~ |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1083 *vim9-access-modes* |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1084 The variable access modes, and their meaning, supported by Vim9class are |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1085 |public-variable| read and write from anywhere |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1086 |read-only-variable| read from anywhere, write from inside the |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1087 class and sub-classes |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1088 |protected-variable| read and write from inside the class and |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1089 sub-classes |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1090 |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1091 The method access modes are similar, but without the read-only mode. |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1092 |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1093 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1094 Default read access to object variables ~ |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1095 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1096 Some users will remark that the access rules for object variables are |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1097 asymmetric. Well, that is intentional. Changing a value is a very different |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1098 action than reading a value. The read operation has no side effects, it can |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1099 be done any number of times without affecting the object. Changing the value |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1100 can have many side effects, and even have a ripple effect, affecting other |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1101 objects. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1102 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1103 When adding object variables one usually doesn't think much about this, just |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1104 get the type right. And normally the values are set in the new() method. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1105 Therefore defaulting to read access only "just works" in most cases. And when |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1106 directly writing you get an error, which makes you wonder if you actually want |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1107 to allow that. This helps writing code with fewer mistakes. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1108 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1109 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1110 Making object variables protected with an underscore ~ |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1111 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1112 When an object variable is protected, it can only be read and changed inside |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1113 the class (and in sub-classes), then it cannot be used outside of the class. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1114 Prepending an underscore is a simple way to make that visible. Various |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1115 programming languages have this as a recommendation. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1116 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1117 In case you change your mind and want to make the object variable accessible |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1118 outside of the class, you will have to remove the underscore everywhere. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1119 Since the name only appears in the class (and sub-classes) they will be easy |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1120 to find and change. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1121 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1122 The other way around is much harder: you can easily prepend an underscore to |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1123 the object variable inside the class to make it protected, but any usage |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1124 elsewhere you will have to track down and change. You may have to make it a |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1125 "set" method call. This reflects the real world problem that taking away |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1126 access requires work to be done for all places where that access exists. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1127 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1128 An alternative would have been using the "protected" keyword, just like |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1129 "public" changes the access in the other direction. Well, that's just to |
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1130 reduce the number of keywords. |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1131 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1132 |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1133 No private object variables ~ |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1134 |
33351
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1135 Some languages provide several ways to control access to object variables. |
a3bbd065fb87
runtime(doc): Vim9: Consistenly use class/object variable and class/object method in help (#13149)
Christian Brabandt <cb@256bit.org>
parents:
33286
diff
changeset
|
1136 The most known is "protected", and the meaning varies from language to |
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1137 language. Others are "shared", "private", "package" and even "friend". |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1138 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1139 These rules make life more difficult. That can be justified in projects where |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1140 many people work on the same, complex code where it is easy to make mistakes. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1141 Especially when refactoring or other changes to the class model. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1142 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1143 The Vim scripts are expected to be used in a plugin, with just one person or a |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1144 small team working on it. Complex rules then only make it more complicated, |
32294 | 1145 the extra safety provided by the rules isn't really needed. Let's just keep |
1146 it simple and not specify access details. | |
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1147 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1148 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1149 ============================================================================== |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1150 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1151 10. To be done later |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1152 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1153 Can a newSomething() constructor invoke another constructor? If yes, what are |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1154 the restrictions? |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1155 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1156 Thoughts: |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1157 - Generics for a class: `class <Tkey, Tentry>` |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1158 - Generics for a function: `def <Tkey> GetLast(key: Tkey)` |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1159 - Mixins: not sure if that is useful, leave out for simplicity. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1160 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1161 Some things that look like good additions: |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1162 - For testing: Mock mechanism |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1163 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1164 An important class to be provided is "Promise". Since Vim is single |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1165 threaded, connecting asynchronous operations is a natural way of allowing |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1166 plugins to do their work without blocking the user. It's a uniform way to |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1167 invoke callbacks and handle timeouts and errors. |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1168 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1169 |
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1170 vim:tw=78:ts=8:noet:ft=help:norl: |