Mercurial > vim
annotate runtime/doc/vim9class.txt @ 33951:45a50fd59a73 v9.0.2170
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Commit: https://github.com/vim/vim/commit/e5437c542709b77ade084f96e60d84d4e847e6d3
Author: Yegappan Lakshmanan <yegappan@yahoo.com>
Date: Sat Dec 16 14:11:19 2023 +0100
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Problem: Vim9: no support for const/final class/objects vars
Solution: Support final and const object and class variables
closes: #13655
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
| author | Christian Brabandt <cb@256bit.org> |
|---|---|
| date | Sat, 16 Dec 2023 14:15:05 +0100 |
| parents | 27746ed6cb05 |
| children | 6d33f47b71b8 |
| rev | line source |
|---|---|
|
33945
27746ed6cb05
runtime(doc): grammar & typo fixes
Christian Brabandt <cb@256bit.org>
parents:
33942
diff
changeset
|
1 *vim9class.txt* For Vim version 9.0. Last change: 2023 Dec 14 |
|
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 |
| 31885 | 7 NOTE - This is not finished yet, anything can still change! - NOTE |
|
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 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
10 Vim9 classes, objects, interfaces, types and enums. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
11 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
12 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
|
13 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
|
14 3. Class variables and methods |Vim9-class-member| |
| 31885 | 15 4. Using an abstract class |Vim9-abstract-class| |
| 16 5. Using an interface |Vim9-using-interface| | |
| 17 6. More class details |Vim9-class| | |
| 18 7. Type definition |Vim9-type| | |
| 19 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
|
20 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
21 9. Rationale |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
22 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
|
23 |
|
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 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
26 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
|
27 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
28 The fancy term is "object-oriented programming". You can find lots of study |
| 31885 | 29 material on this subject. Here we document what |Vim9| script provides, |
| 30 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
|
31 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
|
32 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
|
33 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
34 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
|
35 - 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
|
36 have a value. |
| 31885 | 37 - 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
|
38 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
|
39 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
|
40 - 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
|
41 methods. |
| 31885 | 42 - Objects are created from a class and all objects have the same interface. |
| 43 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
|
44 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
45 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
|
46 - 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
|
47 This method is invoked on the class name: MyClass.new(). |
| 31885 | 48 - 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
|
49 - 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
|
50 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
51 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
|
52 - 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
|
53 - 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
|
54 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
55 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
|
56 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
|
57 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
58 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
59 Class modeling ~ |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
60 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
61 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
|
62 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
|
63 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
|
64 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
|
65 should match your purpose. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
66 |
| 31885 | 67 Keep in mind that composition (an object contains other objects) is often |
| 68 better than inheritance (an object extends another object). Don't waste time | |
| 69 trying to find the optimal class model. Or waste time discussing whether a | |
| 70 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
|
71 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
72 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
73 ============================================================================== |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
74 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
75 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
|
76 |
| 31885 | 77 Let's start with a simple example: a class that stores a text position (see |
| 78 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
|
79 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
80 class TextPosition |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
81 var lnum: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
82 var col: number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
83 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
84 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
|
85 this.lnum = lnum |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
86 this.col = col |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
87 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
88 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
89 def SetLnum(lnum: number) |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
90 this.lnum = lnum |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
91 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
92 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
93 def SetCol(col: number) |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
94 this.col = col |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
95 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
96 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
97 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
|
98 this.lnum = lnum |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
99 this.col = col |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
100 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
101 endclass |
| 31430 | 102 < *object* *Object* |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
103 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
|
104 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
105 var pos = TextPosition.new(1, 1) |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
106 |
|
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
|
107 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
|
108 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
109 echo $'The text position is ({pos.lnum}, {pos.col})' |
| 31430 | 110 < *E1317* *E1327* |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
111 If you have been using other object-oriented languages you will notice that |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
112 in Vim the object members are consistently referred to with the "this." |
| 31885 | 113 prefix. This is different from languages like Java and TypeScript. The |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
114 naming convention makes the object members easy to spot. Also, when a |
|
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
|
115 variable does not have the "this." prefix you know it is not an object |
|
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
|
116 variable. |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
117 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
118 |
|
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
|
119 Object variable write access ~ |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
120 *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
|
121 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
|
122 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
123 pos.lnum = 9 |
| 31885 | 124 < *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
|
125 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
|
126 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
|
127 it: > |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
128 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
129 pos.SetLnum(9) |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
130 |
|
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
|
131 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
|
132 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
|
133 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
|
134 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
|
135 the closest valid value. |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
136 *: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
|
137 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
|
138 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
|
139 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
140 public this.lnum: number |
| 31885 | 141 public this.col: number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
142 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
143 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
|
144 "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
|
145 *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
|
146 If you try to set an object variable that doesn't exist you get an error: > |
| 31579 | 147 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
|
148 < 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
|
149 |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
150 *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
|
151 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
|
152 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
153 Protected variables ~ |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
154 *protected-variable* *E1332* *E1333* |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
155 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
|
156 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
|
157 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
|
158 |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
159 var _lnum: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
160 var _col number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
161 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
162 Now you need to provide methods to get the value of the protected variables. |
| 31885 | 163 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
|
164 "Get": > |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
165 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
166 def GetLnum(): number |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
167 return this._lnum |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
168 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
169 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
170 def GetCol() number |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
171 return this._col |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
172 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
173 |
|
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
|
174 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
|
175 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
|
176 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
|
177 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
178 def GetLnum(): number |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
179 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
|
180 return this._lineCount |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
181 endif |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
182 return this._lnum |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
183 enddef |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
184 < |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
185 Protected methods ~ |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
186 *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
|
187 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
|
188 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
|
189 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
|
190 |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
191 class SomeClass |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
192 def _Foo(): number |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
193 return 10 |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
194 enddef |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
195 def Bar(): number |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
196 return this._Foo() |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
197 enddef |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
198 endclass |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
199 < |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
200 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
|
201 the above class): > |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
202 |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
203 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
|
204 a._Foo() |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
205 < |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
206 Simplifying the new() method ~ |
|
33383
5c12ca4dcd45
patch 9.0.1950: Vim9: error codes spread out
Christian Brabandt <cb@256bit.org>
parents:
33379
diff
changeset
|
207 *new()* *constructor* |
|
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
|
208 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
|
209 see this pattern: > |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
210 |
| 31885 | 211 class SomeClass |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
212 var lnum: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
213 var col: number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
214 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
215 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
|
216 this.lnum = lnum |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
217 this.col = col |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
218 enddef |
| 31885 | 219 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
|
220 < |
|
7c9124711f99
patch 9.0.1948: Vim9: object variable "this." should only be used in constructor
Christian Brabandt <cb@256bit.org>
parents:
33372
diff
changeset
|
221 *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
|
222 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
|
223 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
|
224 provided: > |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
225 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
226 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
|
227 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
228 |
|
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
|
229 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
|
230 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
|
231 new() call is assigned to that object variable. This mechanism comes from the |
| 31885 | 232 Dart language. |
| 233 | |
|
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
|
234 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
|
235 results in a much shorter class definition than what we started with: > |
| 31885 | 236 |
| 237 class TextPosition | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
238 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
|
239 public var col: number |
| 31885 | 240 |
| 241 def new(this.lnum, this.col) | |
| 242 enddef | |
| 243 | |
| 244 def SetPosition(lnum: number, col: number) | |
| 245 this.lnum = lnum | |
| 246 this.col = col | |
| 247 enddef | |
| 248 endclass | |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
249 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
250 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
|
251 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
|
252 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
|
253 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
|
254 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
|
255 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
|
256 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
|
257 |
| 31885 | 258 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
|
259 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
|
260 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
|
261 |
|
33385
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
262 *E1365* |
|
32903
54c01bb98b8e
patch 9.0.1760: vim9 class problem with new() constructor
Christian Brabandt <cb@256bit.org>
parents:
32294
diff
changeset
|
263 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
|
264 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
|
265 |
|
33385
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
266 *E1386* |
|
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
267 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
|
268 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
|
269 name. |
|
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
270 |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
271 ============================================================================== |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
272 |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
273 3. Class Variables and Methods *Vim9-class-member* |
| 31885 | 274 |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
275 *:static* *E1337* *E1338* *E1368* |
| 31885 | 276 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
|
277 prefix in the class where they are defined: > |
| 31885 | 278 |
| 279 class OtherThing | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
280 var size: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
281 static var totalSize: number |
| 31885 | 282 |
| 283 def new(this.size) | |
| 284 totalSize += this.size | |
| 285 enddef | |
| 286 endclass | |
| 287 < *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
|
288 Since the name is used as-is, shadowing the name by a method argument name |
| 31885 | 289 or local variable name is not allowed. |
| 290 | |
|
33385
b5ad84fdc702
patch 9.0.1951: Vim9: hard to debug vim9_class errors from CI
Christian Brabandt <cb@256bit.org>
parents:
33383
diff
changeset
|
291 *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
|
292 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
|
293 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
|
294 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
295 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
|
296 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
|
297 prefixing "public": > |
| 31885 | 298 |
| 299 class OtherThing | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
300 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
|
301 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
|
302 public static var result: number # anybody can read and write |
| 31885 | 303 endclass |
| 304 < | |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
305 *class-method* |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
306 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
|
307 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
|
308 "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
|
309 > |
| 31885 | 310 class OtherThing |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
311 var size: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
312 static var totalSize: number |
| 31885 | 313 |
| 314 # Clear the total size and return the value it had before. | |
| 315 static def ClearTotalSize(): number | |
| 316 var prev = totalSize | |
| 317 totalSize = 0 | |
| 318 return prev | |
| 319 enddef | |
| 320 endclass | |
| 321 | |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
322 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
|
323 class the class name must be prefixed: `OtherThing.ClearTotalSize()`. To use |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
324 a super class method in a child class, the class name must be prefixed. |
| 31885 | 325 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
326 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
|
327 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
|
328 |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
329 class OtherThing |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
330 static def _Foo() |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
331 echo "Foo" |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
332 enddef |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
333 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
|
334 _Foo() |
|
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
335 enddef |
|
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
336 endclass |
|
33068
d42927c6e556
patch 9.0.1821: Vim9 constructors are always static
Christian Brabandt <cb@256bit.org>
parents:
33025
diff
changeset
|
337 < |
|
d42927c6e556
patch 9.0.1821: Vim9 constructors are always static
Christian Brabandt <cb@256bit.org>
parents:
33025
diff
changeset
|
338 *E1370* |
|
d42927c6e556
patch 9.0.1821: Vim9 constructors are always static
Christian Brabandt <cb@256bit.org>
parents:
33025
diff
changeset
|
339 Note that constructors cannot be declared as "static", because they always |
|
d42927c6e556
patch 9.0.1821: Vim9 constructors are always static
Christian Brabandt <cb@256bit.org>
parents:
33025
diff
changeset
|
340 are. |
|
33025
1d18c7fe609f
patch 9.0.1804: Vim9: no support for private object methods
Christian Brabandt <cb@256bit.org>
parents:
32960
diff
changeset
|
341 |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
342 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
|
343 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
|
344 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
|
345 |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
346 vim9script |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
347 class Vehicle |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
348 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
|
349 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
|
350 nextID += 1 |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
351 return nextID |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
352 enddef |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
353 endclass |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
354 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
|
355 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
|
356 def new() |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
357 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
|
358 enddef |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
359 endclass |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
360 < |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
361 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
|
362 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
|
363 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
|
364 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
|
365 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
|
366 |
|
33951
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
367 *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
|
368 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
|
369 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
|
370 |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
371 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
|
372 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
|
373 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
|
374 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
|
375 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
|
376 endclass |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
377 < |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
378 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
|
379 |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
380 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
|
381 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
|
382 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
|
383 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
|
384 enddef |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
385 endclass |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
386 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
|
387 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
|
388 < |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
389 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
|
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 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
|
392 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
|
393 endclass |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
394 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
|
395 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
|
396 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
|
397 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
|
398 < |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
399 *E1408* |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
400 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
|
401 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
|
402 |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
403 *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
|
404 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
|
405 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
|
406 |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
407 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
|
408 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
|
409 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
|
410 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
|
411 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
|
412 endclass |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
413 < |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
414 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
|
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 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
|
417 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
|
418 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
|
419 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
|
420 enddef |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
421 endclass |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
422 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
|
423 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
|
424 < |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
425 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
|
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 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
|
428 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
|
429 endclass |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
430 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
|
431 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
|
432 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
|
433 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
|
434 < |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
435 *E1410* |
|
45a50fd59a73
patch 9.0.2170: Vim9: no support for const/final class/objects vars
Christian Brabandt <cb@256bit.org>
parents:
33945
diff
changeset
|
436 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
|
437 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
|
438 |
| 31885 | 439 ============================================================================== |
| 440 | |
| 441 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
|
442 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
443 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
|
444 model one often finds that a few classes have the same properties that can be |
| 31885 | 445 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
|
446 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
|
447 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
|
448 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
449 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
|
450 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
|
451 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
|
452 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
|
453 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
454 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
|
455 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
|
456 var thickness = 10 |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
457 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
458 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
459 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
|
460 var size: number |
|
31335
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 def new(this.size) |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
463 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
464 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
465 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
466 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
|
467 var base: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
468 var height: number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
469 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
470 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
|
471 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
472 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
473 < |
| 31885 | 474 An abstract class is defined the same way as a normal class, except that it |
| 475 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
|
476 |
|
33798
af1b18018eeb
runtime(doc): Fix whitespace and formatting of some help files (#13549)
Christian Brabandt <cb@256bit.org>
parents:
33738
diff
changeset
|
477 *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
|
478 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
|
479 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
|
480 |
|
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
481 abstract class Shape |
|
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
482 abstract def Draw() |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
483 abstract static def SetColor() |
|
33217
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
484 endclass |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
485 < |
|
33698
643db54ed3e7
patch 9.0.2084: Vim9: abstract static methods are possible
Christian Brabandt <cb@256bit.org>
parents:
33682
diff
changeset
|
486 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
|
487 |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
488 *E1373* |
|
33217
499ba27ba0f6
patch 9.0.1885: Vim9: no support for abstract methods
Christian Brabandt <cb@256bit.org>
parents:
33068
diff
changeset
|
489 A class extending the abstract class must implement all the abstract methods. |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
490 The signature (arguments, argument types and return type) must be exactly the |
|
33490
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
491 same. If the return type of a method is a class, then that class or one of |
|
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
492 its subclasses can be used in the extended method. Class methods in an |
|
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
493 abstract class can also be abstract methods. |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
494 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
495 ============================================================================== |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
496 |
| 31885 | 497 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
|
498 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
499 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
|
500 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
|
501 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
|
502 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
|
503 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
504 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
|
505 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
|
506 var thickness = 10 |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
507 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
508 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
509 interface HasSurface |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
510 def Surface(): number |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
511 endinterface |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
512 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
513 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
|
514 var size: number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
515 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
516 def new(this.size) |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
517 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
518 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
519 def Surface(): number |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
520 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
|
521 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
522 endclass |
|
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 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
|
525 var base: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
526 var height: number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
527 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
528 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
|
529 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
530 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
531 def Surface(): number |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
532 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
|
533 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
534 endclass |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
535 < |
|
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
536 *E1348* *E1349* *E1367* *E1382* *E1383* |
| 31671 | 537 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
|
538 interface must appear in the class, with the same types. |
| 31671 | 539 |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
540 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
|
541 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
542 var shapes: list<HasSurface> = [ |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
543 Square.new(12), |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
544 Triangle.new(8, 15), |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
545 ] |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
546 for shape in shapes |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
547 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
|
548 endfor |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
549 < |
|
33372
3e9a91624b40
patch 9.0.1945: Vim9: missing support for ro-vars in interface
Christian Brabandt <cb@256bit.org>
parents:
33351
diff
changeset
|
550 *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
|
551 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
|
552 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
|
553 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
|
554 |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
555 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
|
556 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
|
557 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
558 ============================================================================== |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
559 |
| 31885 | 560 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
|
561 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
562 Defining a class ~ |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
563 *:class* *:endclass* *:abstract* |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
564 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
|
565 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
|
566 |
| 31430 | 567 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
|
568 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
|
569 |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
570 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
|
571 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
|
572 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
|
573 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
574 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
|
575 these variants: > |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
576 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
577 class ClassName |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
578 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
579 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
580 export class ClassName |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
581 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
582 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
583 abstract class ClassName |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
584 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
585 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
586 export abstract class ClassName |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
587 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
588 < |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
589 *E1314* |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
590 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
|
591 That avoids clashing with builtin types. |
| 31430 | 592 *E1315* |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
593 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
|
594 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
|
595 extends ClassName |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
596 implements InterfaceName, OtherInterface |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
597 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
|
598 < *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
|
599 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
|
600 define a method with the same name and different type of arguments. It is not |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
601 possible to use a public and protected member variable with the same name. A |
|
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
|
602 object variable name used in a super class cannot be reused in a child class. |
| 31885 | 603 |
| 604 | |
|
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
|
605 Object Variable Initialization ~ |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
606 |
|
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
|
607 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
|
608 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
|
609 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
|
610 |
|
33401
bb99820510ef
patch 9.0.1959: Vim9: methods parameters and types are covariant
Christian Brabandt <cb@256bit.org>
parents:
33385
diff
changeset
|
611 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
|
612 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
|
613 "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
|
614 "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
|
615 |
| 31885 | 616 Extending a class ~ |
| 617 *extends* | |
| 31671 | 618 A class can extend one other class. *E1352* *E1353* *E1354* |
| 31885 | 619 The basic idea is to build on top of an existing class, add properties to it. |
| 620 | |
| 621 The extended class is called the "base class" or "super class". The new class | |
| 622 is called the "child class". | |
| 623 | |
|
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
|
624 Object variables from the base class are all taken over by the child class. It |
| 31885 | 625 is not possible to override them (unlike some other languages). |
| 626 | |
| 627 *E1356* *E1357* *E1358* | |
|
33432
97ceabebaeaf
patch 9.0.1974: vim9: using contra-variant type-checks
Christian Brabandt <cb@256bit.org>
parents:
33401
diff
changeset
|
628 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
|
629 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
|
630 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
|
631 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
|
632 prefixing "super.". |
| 31885 | 633 |
|
33286
0c3553cfe22e
patch 9.0.1909: Vim9: problem calling class method from other class
Christian Brabandt <cb@256bit.org>
parents:
33217
diff
changeset
|
634 *E1377* |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
635 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
|
636 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
|
637 |
| 31885 | 638 Other object methods of the base class are taken over by the child class. |
| 639 | |
|
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
|
640 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
|
641 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
|
642 the name of the class (for class methods) or "super.". |
| 31885 | 643 |
| 644 Unlike other languages, the constructor of the base class does not need to be | |
| 645 invoked. In fact, it cannot be invoked. If some initialization from the base | |
| 646 class also needs to be done in a child class, put it in an object method and | |
| 647 call that method from every constructor(). | |
| 648 | |
|
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
|
649 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
|
650 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
|
651 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
|
652 will be added automatically. |
| 31885 | 653 |
| 654 | |
| 655 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
|
656 *implements* *E1346* *E1347* *E1389* |
| 31671 | 657 A class can implement one or more interfaces. The "implements" keyword can |
| 658 only appear once *E1350* . Multiple interfaces can be specified, separated by | |
| 659 commas. Each interface name can appear only once. *E1351* | |
| 31885 | 660 |
| 661 | |
| 662 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
|
663 *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
|
664 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
|
665 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
|
666 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
|
667 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
668 |
| 31430 | 669 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
|
670 *E1318* *E1325* *E1388* |
| 32061 | 671 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
|
672 - 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
|
673 var _protectedVariableName: memberType |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
674 var readonlyVariableName: memberType |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
675 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
|
676 - 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
|
677 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
|
678 static var readonlyClassVariableName: memberType |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
679 static var public readwriteClassVariableName: memberType |
| 31430 | 680 - A constructor method: > |
| 32004 | 681 def new(arguments) |
| 682 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
|
683 - 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
|
684 static def SomeMethod(arguments) |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
685 static def _ProtectedMethod(arguments) |
| 31430 | 686 - An object method: > |
| 32004 | 687 def SomeMethod(arguments) |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
688 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
|
689 |
|
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
|
690 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
|
691 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
|
692 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
|
693 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
|
694 For example: > |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
695 var nameList = [] |
| 31579 | 696 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
|
697 var nameList: list<string> |
| 31579 | 698 The initialization isn't needed, the list is empty by default. |
| 699 *E1330* | |
| 700 Some types cannot be used, such as "void", "null" and "v:none". | |
| 31430 | 701 |
| 702 | |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
703 Defining an interface ~ |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
704 *:interface* *:endinterface* |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
705 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
|
706 prefixed with `:export`: > |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
707 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
708 interface InterfaceName |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
709 endinterface |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
710 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
711 export interface InterfaceName |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
712 endinterface |
| 31671 | 713 < *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
|
714 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
|
715 any initializer. |
| 31671 | 716 *E1345* |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
717 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
|
718 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
|
719 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
720 interface HasSurface |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
721 var size: number |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
722 def Surface(): number |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
723 endinterface |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
724 |
| 31671 | 725 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
|
726 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
|
727 name, with a hint about what it provides. |
| 31671 | 728 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
|
729 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
|
730 interface. *E1381* |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
731 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
732 |
| 32004 | 733 null object ~ |
| 734 | |
| 32061 | 735 When a variable is declared to have the type of an object, but it is not |
| 32004 | 736 initialized, the value is null. When trying to use this null object Vim often |
| 737 does not know what class was supposed to be used. Vim then cannot check if | |
|
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
|
738 a variable name is correct and you will get an "Using a null object" error, |
|
33434
484543479bd7
runtime(doc): fix typos.
Christian Brabandt <cb@256bit.org>
parents:
33432
diff
changeset
|
739 even when the variable name is invalid. *E1360* *E1362* |
| 32004 | 740 |
| 741 | |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
742 Default constructor ~ |
|
33383
5c12ca4dcd45
patch 9.0.1950: Vim9: error codes spread out
Christian Brabandt <cb@256bit.org>
parents:
33379
diff
changeset
|
743 *default-constructor* |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
744 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
|
745 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
|
746 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
|
747 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
748 class AutoNew |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
749 var name: string |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
750 var age: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
751 var gender: Gender |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
752 endclass |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
753 |
|
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
|
754 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
|
755 |
|
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
756 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
|
757 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
758 |
|
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
759 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
|
760 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
|
761 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
|
762 with default values: > |
| 31430 | 763 |
| 764 class TextPosition | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
765 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
|
766 var col: number = 1 |
| 31430 | 767 endclass |
| 768 | |
| 769 If you want the constructor to have mandatory arguments, you need to write it | |
| 770 yourself. For example, if for the AutoNew class above you insist on getting | |
| 771 the name, you can define the constructor like this: > | |
| 772 | |
|
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
773 def new(this.name, this.age = v:none, this.gender = v:none) |
| 31430 | 774 enddef |
|
33891
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
775 < |
|
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
776 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
|
777 the class is changed later, then all the callers of the default new() method |
|
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
778 needs to change. To avoid this, the new() method can be explicitly defined |
|
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
779 without any arguments. |
|
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
780 |
|
56b32a00f325
runtime(doc): update todo items (#13631)
Christian Brabandt <cb@256bit.org>
parents:
33798
diff
changeset
|
781 *E1328* |
|
31441
e572ff386670
patch 9.0.1053: default constructor arguments are not optional
Bram Moolenaar <Bram@vim.org>
parents:
31430
diff
changeset
|
782 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
|
783 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
|
784 way you only need to look in one place for the default values. |
| 31430 | 785 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
786 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
|
787 protected access ones. |
| 31671 | 788 |
|
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
|
789 If the class extends another one, the object variables of that class will come |
| 31671 | 790 first. |
| 791 | |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
792 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
793 Multiple constructors ~ |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
794 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
795 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
|
796 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
|
797 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
|
798 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
|
799 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
800 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
|
801 enddef |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
802 ... |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
803 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
|
804 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
|
805 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
|
806 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
807 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
|
808 includes it: > |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
809 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
810 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
|
811 this.color = Color.black |
|
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 = newBlack(Garment.pants, "XL") |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
815 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
|
816 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
|
817 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
818 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
|
819 "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
|
820 constructor methods. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
821 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
822 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
823 ============================================================================== |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
824 |
| 31885 | 825 7. Type definition *Vim9-type* *:type* |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
826 |
|
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
827 *E1393* *E1395* *E1396* *E1397* *E1398* |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
828 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
|
829 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
|
830 can be used. Example: > |
|
33490
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
831 |
|
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
832 type ListOfStrings = list<string> |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
833 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
|
834 |
|
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
835 def ProcessStr(str: ListOfStrings): ListOfStrings |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
836 return str |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
837 enddef |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
838 echo ProcessStr(s) |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
839 < |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
840 *E1394* |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
841 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
|
842 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
|
843 |
|
33931
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
844 *E1399* |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
845 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
|
846 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
|
847 |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
848 *E1400* *E1401* *E1402* *E1403* *E1407* |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
849 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
|
850 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
|
851 |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
852 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
|
853 aliased: > |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
854 |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
855 type ListOfStudents = list<dict<any>> |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
856 echo typename(ListOfStudents) |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
857 typealias<list<dict<any>>> |
|
050160b94f02
patch 9.0.2162: Vim9: type documentation out-dated
Christian Brabandt <cb@256bit.org>
parents:
33891
diff
changeset
|
858 < |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
859 ============================================================================== |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
860 |
| 31885 | 861 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
|
862 |
|
33490
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
863 {not implemented yet} |
|
33593174288b
runtime(doc): Update vim9class help (#13292)
Christian Brabandt <cb@256bit.org>
parents:
33434
diff
changeset
|
864 |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
865 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
|
866 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
867 :enum Color |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
868 White |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
869 Red |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
870 Green |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
871 Blue |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
872 Black |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
873 :endenum |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
874 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
875 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
876 ============================================================================== |
|
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 9. Rationale |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
879 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
880 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
|
881 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
|
882 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
|
883 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
|
884 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
885 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
|
886 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
|
887 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
|
888 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
|
889 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
|
890 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
|
891 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
|
892 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
893 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
|
894 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
|
895 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
|
896 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
|
897 understand. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
898 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
899 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
|
900 - Keep it simple. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
901 - 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
|
902 - 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
|
903 - 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
|
904 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
|
905 - Keep it consistent. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
906 - 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
|
907 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
908 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
909 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
|
910 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
911 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
|
912 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
|
913 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
|
914 disadvantage. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
915 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
916 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
|
917 "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
|
918 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
|
919 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
920 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
|
921 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
|
922 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
|
923 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
924 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
925 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
|
926 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
927 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
|
928 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
|
929 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
|
930 constructor. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
931 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
932 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
|
933 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
|
934 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
|
935 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
|
936 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
|
937 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
|
938 returning. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
939 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
940 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
|
941 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
|
942 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
|
943 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
|
944 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
945 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
946 No overloading of methods ~ |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
947 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
948 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
|
949 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
|
950 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
|
951 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
|
952 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
|
953 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
954 |
| 31671 | 955 Single inheritance and interfaces ~ |
| 956 | |
| 957 Some languages support multiple inheritance. Although that can be useful in | |
| 958 some cases, it makes the rules of how a class works quite complicated. | |
| 959 Instead, using interfaces to declare what is supported is much simpler. The | |
| 960 very popular Java language does it this way, and it should be good enough for | |
| 31885 | 961 Vim. The "keep it simple" rule applies here. |
| 31671 | 962 |
| 963 Explicitly declaring that a class supports an interface makes it easy to see | |
| 964 what a class is intended for. It also makes it possible to do proper type | |
| 965 checking. When an interface is changed any class that declares to implement | |
| 966 it will be checked if that change was also changed. The mechanism to assume a | |
| 967 class implements an interface just because the methods happen to match is | |
| 968 brittle and leads to obscure problems, let's not do that. | |
| 969 | |
| 970 | |
|
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
|
971 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
|
972 |
|
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
|
973 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
|
974 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
|
975 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
|
976 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
|
977 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
978 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
|
979 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
|
980 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
|
981 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
|
982 inconsistent. |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
983 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
984 For |Vim9| classes the "this." prefix is always used. Also for declaring 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
|
985 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
|
986 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
|
987 which aren't. |
|
31335
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 |
|
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 Using class variables ~ |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
991 |
|
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
|
992 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
|
993 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
|
994 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
|
995 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
|
996 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
|
997 |
|
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
|
998 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
|
999 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
|
1000 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
|
1001 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
|
1002 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1003 |
|
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
|
1004 Declaring object and class variables ~ |
| 31671 | 1005 |
| 1006 The main choice is whether to use "var" as with variable declarations. | |
| 1007 TypeScript does not use it: > | |
| 1008 class Point { | |
| 1009 x: number; | |
| 1010 y = 0; | |
| 1011 } | |
| 1012 | |
|
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
|
1013 Following that Vim object variables could be declared like this: > |
| 31671 | 1014 class Point |
| 1015 this.x: number | |
| 1016 this.y = 0 | |
| 1017 endclass | |
| 1018 | |
| 1019 Some users pointed out that this looks more like an assignment than a | |
| 1020 declaration. Adding "var" changes that: > | |
| 1021 class Point | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1022 var x: number |
|
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1023 var y = 0 |
| 31671 | 1024 endclass |
| 1025 | |
|
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
|
1026 We also need to be able to declare class variables using the "static" keyword. |
| 31671 | 1027 There we can also choose to leave out "var": > |
| 1028 class Point | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1029 var x: number |
| 31671 | 1030 static count = 0 |
| 1031 endclass | |
| 1032 | |
| 1033 Or do use it, before "static": > | |
| 1034 class Point | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1035 var x: number |
| 31671 | 1036 var static count = 0 |
| 1037 endclass | |
| 1038 | |
| 1039 Or after "static": > | |
| 1040 class Point | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1041 var x: number |
| 31671 | 1042 static var count = 0 |
| 1043 endclass | |
| 1044 | |
| 1045 This is more in line with "static def Func()". | |
| 1046 | |
| 1047 There is no clear preference whether to use "var" or not. The two main | |
| 1048 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
|
1049 1. TypeScript and other popular languages do not use it. |
| 31671 | 1050 2. Less clutter. |
| 1051 | |
|
33942
3bba09502b8d
patch 9.0.2167: Vim9: not consistently using :var for declarations
Christian Brabandt <cb@256bit.org>
parents:
33931
diff
changeset
|
1052 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
|
1053 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
|
1054 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
|
1055 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
|
1056 |
| 31671 | 1057 |
|
31335
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1058 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
|
1059 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1060 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
|
1061 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
|
1062 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
|
1063 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
|
1064 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1065 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
|
1066 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
|
1067 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
|
1068 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
|
1069 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1070 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1071 Vim9class access modes ~ |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1072 *vim9-access-modes* |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1073 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
|
1074 |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
|
1075 |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
|
1076 class and sub-classes |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1077 |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
|
1078 sub-classes |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1079 |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1080 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
|
1081 |
|
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1082 |
|
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
|
1083 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
|
1084 |
|
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
|
1085 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
|
1086 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
|
1087 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
|
1088 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
|
1089 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
|
1090 objects. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1091 |
|
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
|
1092 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
|
1093 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
|
1094 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
|
1095 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
|
1096 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
|
1097 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1098 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1099 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
|
1100 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1101 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
|
1102 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
|
1103 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
|
1104 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
|
1105 |
|
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
|
1106 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
|
1107 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
|
1108 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
|
1109 to find and change. |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1110 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1111 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
|
1112 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
|
1113 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
|
1114 "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
|
1115 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
|
1116 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1117 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
|
1118 "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
|
1119 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
|
1120 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1121 |
|
33738
2172872dfbcd
patch 9.0.2096: Vim9: confusing usage of private
Christian Brabandt <cb@256bit.org>
parents:
33698
diff
changeset
|
1122 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
|
1123 |
|
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 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
|
1125 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
|
1126 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
|
1127 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1128 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
|
1129 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
|
1130 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
|
1131 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1132 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
|
1133 small team working on it. Complex rules then only make it more complicated, |
| 32294 | 1134 the extra safety provided by the rules isn't really needed. Let's just keep |
| 1135 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
|
1136 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1137 |
|
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 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1140 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
|
1141 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1142 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
|
1143 the restrictions? |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1144 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1145 Thoughts: |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1146 - 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
|
1147 - 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
|
1148 - 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
|
1149 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1150 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
|
1151 - For testing: Mock mechanism |
|
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 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
|
1154 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
|
1155 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
|
1156 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
|
1157 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1158 |
|
5acc0d2cf4f7
patch 9.0.1001: classes are not documented or implemented yet
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
1159 vim:tw=78:ts=8:noet:ft=help:norl: |