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annotate runtime/doc/vim9.txt @ 27459:5825405e4e2c
Update runtime files
Commit: https://github.com/vim/vim/commit/f10911e5db16f1fe6ab519c5d091ad0c1df0d063
Author: Bram Moolenaar <Bram@vim.org>
Date: Sat Jan 29 22:20:48 2022 +0000
Update runtime files
| author | Bram Moolenaar <Bram@vim.org> |
|---|---|
| date | Sat, 29 Jan 2022 23:30:04 +0100 |
| parents | 3649b5a6b1b6 |
| children | 4789f29c9595 |
| rev | line source |
|---|---|
| 27459 | 1 *vim9.txt* For Vim version 8.2. Last change: 2022 Jan 29 |
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4 VIM REFERENCE MANUAL by Bram Moolenaar |
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7 Vim9 script commands and expressions. *Vim9* *vim9* |
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9 Most expression help is in |eval.txt|. This file is about the new syntax and |
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10 features in Vim9 script. |
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| 23466 | 14 1. What is Vim9 script? |Vim9-script| |
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15 2. Differences |vim9-differences| |
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16 3. New style functions |fast-functions| |
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17 4. Types |vim9-types| |
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18 5. Namespace, Import and Export |vim9script| |
| 22328 | 19 6. Future work: classes |vim9-classes| |
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21 9. Rationale |vim9-rationale| |
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23 ============================================================================== |
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24 |
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25 1. What is Vim9 script? *Vim9-script* |
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26 |
| 20241 | 27 Vim script has been growing over time, while preserving backwards |
| 28 compatibility. That means bad choices from the past often can't be changed | |
| 20965 | 29 and compatibility with Vi restricts possible solutions. Execution is quite |
| 20241 | 30 slow, each line is parsed every time it is executed. |
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31 |
| 20241 | 32 The main goal of Vim9 script is to drastically improve performance. This is |
| 33 accomplished by compiling commands into instructions that can be efficiently | |
| 34 executed. An increase in execution speed of 10 to 100 times can be expected. | |
| 35 | |
| 36 A secondary goal is to avoid Vim-specific constructs and get closer to | |
| 37 commonly used programming languages, such as JavaScript, TypeScript and Java. | |
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38 |
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39 The performance improvements can only be achieved by not being 100% backwards |
| 20552 | 40 compatible. For example, making function arguments available in the |
| 41 "a:" dictionary adds quite a lot of overhead. In a Vim9 function this | |
| 42 dictionary is not available. Other differences are more subtle, such as how | |
| 43 errors are handled. | |
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44 |
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45 The Vim9 script syntax and semantics are used in: |
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46 - a function defined with the `:def` command |
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47 - a script file where the first command is `vim9script` |
| 22328 | 48 - an autocommand defined in the context of the above |
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49 - a command prefixed with the `vim9cmd` command modifier |
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50 |
| 23573 | 51 When using `:function` in a Vim9 script file the legacy syntax is used, with |
| 52 the highest |scriptversion|. However, this can be confusing and is therefore | |
| 53 discouraged. | |
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54 |
| 20241 | 55 Vim9 script and legacy Vim script can be mixed. There is no requirement to |
| 22328 | 56 rewrite old scripts, they keep working as before. You may want to use a few |
| 57 `:def` functions for code that needs to be fast. | |
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58 |
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59 :vim9[cmd] {cmd} *:vim9* *:vim9cmd* |
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60 Execute {cmd} using Vim9 script syntax and semantics. |
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61 Useful when typing a command and in a legacy script or |
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62 function. |
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63 |
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64 :leg[acy] {cmd} *:leg* *:legacy* |
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65 Execute {cmd} using legacy script syntax and semantics. Only |
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66 useful in a Vim9 script or a :def function. |
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67 Note that {cmd} cannot use local variables, since it is parsed |
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68 with legacy expression syntax. |
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69 |
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70 ============================================================================== |
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71 |
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72 2. Differences from legacy Vim script *vim9-differences* |
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73 |
| 22441 | 74 Overview ~ |
| 75 | |
| 76 Brief summary of the differences you will most often encounter when using Vim9 | |
| 77 script and `:def` functions; details are below: | |
| 78 - Comments start with #, not ": > | |
| 23573 | 79 echo "hello" # comment |
| 22441 | 80 - Using a backslash for line continuation is hardly ever needed: > |
| 23573 | 81 echo "hello " |
| 22441 | 82 .. yourName |
| 83 .. ", how are you?" | |
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84 - White space is required in many places to improve readability. |
| 27459 | 85 - Assign values without `:let` *E1126* , declare variables with `:var`: > |
| 23573 | 86 var count = 0 |
| 22441 | 87 count += 3 |
| 88 - Constants can be declared with `:final` and `:const`: > | |
| 23573 | 89 final matches = [] # add matches |
| 22441 | 90 const names = ['Betty', 'Peter'] # cannot be changed |
| 91 - `:final` cannot be used as an abbreviation of `:finally`. | |
| 92 - Variables and functions are script-local by default. | |
| 93 - Functions are declared with argument types and return type: > | |
| 94 def CallMe(count: number, message: string): bool | |
| 95 - Call functions without `:call`: > | |
| 23573 | 96 writefile(['done'], 'file.txt') |
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97 - You cannot use old Ex commands `:xit`, `:t`, `:k`, `:append`, `:change`, |
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98 `:insert`, `:open`, and `:s` or `:d` with only flags. |
| 25973 | 99 - You cannot use curly-braces names. |
| 22441 | 100 - A range before a command must be prefixed with a colon: > |
| 23573 | 101 :%s/this/that |
| 25700 | 102 - Executing a register with "@r" does not work, you can prepend a colon or use |
| 103 `:exe`: > | |
| 104 :exe @a | |
| 23573 | 105 - Unless mentioned specifically, the highest |scriptversion| is used. |
| 27162 | 106 - When defining an expression mapping, the expression will be evaluated in the |
| 107 context of the script where it was defined. | |
| 22441 | 108 |
| 109 | |
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110 Comments starting with # ~ |
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111 |
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112 In legacy Vim script comments start with double quote. In Vim9 script |
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113 comments start with #. > |
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114 # declarations |
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115 var count = 0 # number of occurrences |
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116 |
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117 The reason is that a double quote can also be the start of a string. In many |
| 21825 | 118 places, especially halfway through an expression with a line break, it's hard |
| 119 to tell what the meaning is, since both a string and a comment can be followed | |
| 120 by arbitrary text. To avoid confusion only # comments are recognized. This | |
| 121 is the same as in shell scripts and Python programs. | |
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122 |
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123 In Vi # is a command to list text with numbers. In Vim9 script you can use |
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124 `:number` for that. > |
| 27036 | 125 :101 number |
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126 |
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127 To improve readability there must be a space between a command and the # |
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128 that starts a comment: > |
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129 var name = value # comment |
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130 var name = value# error! |
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131 |
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132 Do not start a comment with #{, it looks like the legacy dictionary literal |
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133 and produces an error where this might be confusing. #{{ or #{{{ are OK, |
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134 these can be used to start a fold. |
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135 |
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136 In legacy Vim script # is also used for the alternate file name. In Vim9 |
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137 script you need to use %% instead. Instead of ## use %%% (stands for all |
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138 arguments). |
| 20115 | 139 |
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140 |
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141 Vim9 functions ~ |
| 27459 | 142 *E1099* |
| 20241 | 143 A function defined with `:def` is compiled. Execution is many times faster, |
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144 often 10 to 100 times. |
| 20241 | 145 |
| 20552 | 146 Many errors are already found when compiling, before the function is executed. |
| 20241 | 147 The syntax is strict, to enforce code that is easy to read and understand. |
| 148 | |
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149 Compilation is done when any of these is encountered: |
| 23164 | 150 - the first time the function is called |
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151 - when the `:defcompile` command is encountered in the script after the |
| 21991 | 152 function was defined |
| 153 - `:disassemble` is used for the function. | |
| 154 - a function that is compiled calls the function or uses it as a function | |
| 25700 | 155 reference (so that the argument and return types can be checked) |
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156 *E1091* |
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157 If compilation fails it is not tried again on the next call, instead this |
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158 error is given: "E1091: Function is not compiled: {name}". |
| 24569 | 159 Compilation will fail when encountering a user command that has not been |
| 160 created yet. In this case you can call `execute()` to invoke it at runtime. > | |
| 161 def MyFunc() | |
| 162 execute('DefinedLater') | |
| 163 enddef | |
| 20552 | 164 |
| 165 `:def` has no options like `:function` does: "range", "abort", "dict" or | |
| 23164 | 166 "closure". A `:def` function always aborts on an error (unless `:silent!` was |
| 26708 | 167 used for the command or the error was caught a `:try` block), does not get a |
| 168 range passed cannot be a "dict" function, and can always be a closure. | |
| 25700 | 169 *vim9-no-dict-function* |
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170 Later classes will be added, which replaces the "dict function" mechanism. |
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171 For now you will need to pass the dictionary explicitly: > |
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172 def DictFunc(d: dict<any>, arg: string) |
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173 echo d[arg] |
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174 enddef |
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175 var d = {item: 'value', func: DictFunc} |
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176 d.func(d, 'item') |
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177 |
| 25836 | 178 You can call a legacy dict function though: > |
| 179 func Legacy() dict | |
| 180 echo self.value | |
| 181 endfunc | |
| 182 def CallLegacy() | |
| 183 var d = {func: Legacy, value: 'text'} | |
| 184 d.func() | |
| 185 enddef | |
| 27459 | 186 < *E1096* |
| 20241 | 187 The argument types and return type need to be specified. The "any" type can |
| 188 be used, type checking will then be done at runtime, like with legacy | |
| 189 functions. | |
| 27459 | 190 *E1106* |
| 21825 | 191 Arguments are accessed by name, without "a:", just like any other language. |
| 192 There is no "a:" dictionary or "a:000" list. | |
| 27321 | 193 *vim9-variable-arguments* *E1055* |
| 20241 | 194 Variable arguments are defined as the last argument, with a name and have a |
| 21825 | 195 list type, similar to TypeScript. For example, a list of numbers: > |
| 22171 | 196 def MyFunc(...itemlist: list<number>) |
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197 for item in itemlist |
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198 ... |
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199 |
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200 When a function argument is optional (it has a default value) passing `v:none` |
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201 as the argument results in using the default value. This is useful when you |
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202 want to specify a value for an argument that comes after an argument that |
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203 should use its default value. Example: > |
| 25973 | 204 def MyFunc(one = 'one', last = 'last') |
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205 ... |
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206 enddef |
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207 MyFunc(v:none, 'LAST') # first argument uses default value 'one' |
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208 < |
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209 *vim9-ignored-argument* |
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210 The argument "_" (an underscore) can be used to ignore the argument. This is |
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211 most useful in callbacks where you don't need it, but do need to give an |
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212 argument to match the call. E.g. when using map() two arguments are passed, |
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213 the key and the value, to ignore the key: > |
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214 map(myList, (_, v) => v * 2) |
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215 There is no error for using the "_" argument multiple times. No type needs to |
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216 be given. |
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217 |
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218 |
| 20241 | 219 Functions and variables are script-local by default ~ |
| 20856 | 220 *vim9-scopes* |
| 20115 | 221 When using `:function` or `:def` to specify a new function at the script level |
| 222 in a Vim9 script, the function is local to the script, as if "s:" was | |
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223 prefixed. Using the "s:" prefix is optional. To define a global function or |
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224 variable the "g:" prefix must be used. For functions in an autoload script |
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225 the "name#" prefix is sufficient. > |
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226 def ThisFunction() # script-local |
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227 def s:ThisFunction() # script-local |
| 22171 | 228 def g:ThatFunction() # global |
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229 def scriptname#function() # autoload |
| 27321 | 230 < *E1058* *E1075* |
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231 When using `:function` or `:def` to specify a nested function inside a `:def` |
| 26438 | 232 function and no namespace was given, this nested function is local to the code |
| 233 block it is defined in. In a `:def` function it is not possible to define a | |
| 234 script-local function. It is possible to define a global function by using | |
| 235 the "g:" prefix. | |
| 20115 | 236 |
| 237 When referring to a function and no "s:" or "g:" prefix is used, Vim will | |
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238 search for the function: |
| 22565 | 239 - in the function scope, in block scopes |
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240 - in the script scope, possibly imported |
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241 |
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242 Since a script-local function reference can be used without "s:" the name must |
| 24278 | 243 start with an upper case letter even when using the "s:" prefix. In legacy |
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244 script "s:funcref" could be used, because it could not be referred to with |
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245 "funcref". In Vim9 script it can, therefore "s:Funcref" must be used to avoid |
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246 that the name interferes with builtin functions. |
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247 |
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248 In all cases the function must be defined before used. That is when it is |
| 22723 | 249 called, when `:defcompile` causes it to be compiled, or when code that calls |
| 250 it is being compiled (to figure out the return type). | |
| 20241 | 251 |
| 21676 | 252 The result is that functions and variables without a namespace can usually be |
| 20241 | 253 found in the script, either defined there or imported. Global functions and |
| 21676 | 254 variables could be defined anywhere (good luck finding out where!). |
| 27459 | 255 *E1102* |
| 21825 | 256 Global functions can still be defined and deleted at nearly any time. In |
| 20317 | 257 Vim9 script script-local functions are defined once when the script is sourced |
| 20552 | 258 and cannot be deleted or replaced. |
| 20115 | 259 |
| 23305 | 260 When compiling a function and a function call is encountered for a function |
| 261 that is not (yet) defined, the |FuncUndefined| autocommand is not triggered. | |
| 262 You can use an autoload function if needed, or call a legacy function and have | |
| 263 |FuncUndefined| triggered there. | |
| 264 | |
| 20115 | 265 |
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266 Reloading a Vim9 script clears functions and variables by default ~ |
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267 *vim9-reload* |
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268 When loading a legacy Vim script a second time nothing is removed, the |
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269 commands will replace existing variables and functions and create new ones. |
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270 |
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271 When loading a Vim9 script a second time all existing script-local functions |
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272 and variables are deleted, thus you start with a clean slate. This is useful |
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273 if you are developing a plugin and want to try a new version. If you renamed |
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274 something you don't have to worry about the old name still hanging around. |
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275 |
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276 If you do want to keep items, use: > |
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277 vim9script noclear |
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278 |
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279 You want to use this in scripts that use a `finish` command to bail out at |
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280 some point when loaded again. E.g. when a buffer local option is set: > |
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281 vim9script noclear |
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282 setlocal completefunc=SomeFunc |
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283 if exists('*g:SomeFunc') | finish | endif |
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284 def g:SomeFunc() |
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285 .... |
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286 |
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287 |
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288 Variable declarations with :var, :final and :const ~ |
| 27459 | 289 *vim9-declaration* *:var* |
| 290 *E1017* *E1020* *E1054* *E1087* *E1108* *E1124* | |
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291 Local variables need to be declared with `:var`. Local constants need to be |
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292 declared with `:final` or `:const`. We refer to both as "variables" in this |
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293 section. |
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294 |
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295 Variables can be local to a script, function or code block: > |
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296 vim9script |
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297 var script_var = 123 |
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298 def SomeFunc() |
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299 var func_var = script_var |
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300 if cond |
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301 var block_var = func_var |
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302 ... |
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303 |
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304 The variables are only visible in the block where they are defined and nested |
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305 blocks. Once the block ends the variable is no longer accessible: > |
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306 if cond |
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307 var inner = 5 |
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308 else |
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309 var inner = 0 |
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310 endif |
| 22171 | 311 echo inner # Error! |
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312 |
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313 The declaration must be done earlier: > |
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314 var inner: number |
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315 if cond |
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316 inner = 5 |
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317 else |
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318 inner = 0 |
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319 endif |
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320 echo inner |
| 27459 | 321 < *E1025* *E1128* |
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322 To intentionally hide a variable from code that follows, a block can be |
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323 used: > |
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324 { |
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325 var temp = 'temp' |
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326 ... |
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327 } |
| 22171 | 328 echo temp # Error! |
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329 |
| 25402 | 330 This is especially useful in a user command: > |
| 331 | |
| 332 command -range Rename { | |
| 25619 | 333 var save = @a |
| 334 @a = 'some expression' | |
| 335 echo 'do something with ' .. @a | |
| 336 @a = save | |
| 337 } | |
| 25402 | 338 |
| 339 And with autocommands: > | |
| 340 | |
| 341 au BufWritePre *.go { | |
| 25619 | 342 var save = winsaveview() |
| 343 silent! exe ':%! some formatting command' | |
| 344 winrestview(save) | |
| 345 } | |
| 25402 | 346 |
| 347 Although using a :def function probably works better. | |
| 27459 | 348 *E1022* *E1103* *E1130* *E1131* *E1133* *E1134* |
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349 Declaring a variable with a type but without an initializer will initialize to |
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350 false (for bool), empty (for string, list, dict, etc.) or zero (for number, |
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351 any, etc.). This matters especially when using the "any" type, the value will |
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352 default to the number zero. |
| 27321 | 353 *E1016* *E1052* *E1066* |
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354 In Vim9 script `:let` cannot be used. An existing variable is assigned to |
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355 without any command. The same for global, window, tab, buffer and Vim |
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356 variables, because they are not really declared. Those can also be deleted |
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357 with `:unlet`. |
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358 |
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359 `:lockvar` does not work on local variables. Use `:const` and `:final` |
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360 instead. |
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361 |
| 25619 | 362 The `exists()` and `exists_compiled()` functions do not work on local variables |
| 363 or arguments. | |
| 27321 | 364 *E1006* *E1041* |
| 24024 | 365 Variables, functions and function arguments cannot shadow previously defined |
| 366 or imported variables and functions in the same script file. | |
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367 Variables may shadow Ex commands, rename the variable if needed. |
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368 |
| 24387 | 369 Global variables must be prefixed with "g:", also at the script level. > |
| 19968 | 370 vim9script |
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371 var script_local = 'text' |
| 21499 | 372 g:global = 'value' |
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373 var Funcref = g:ThatFunction |
| 19968 | 374 |
| 24387 | 375 Global functions must be prefixed with "g:" when defining them, but can be |
| 376 called without "g:". > | |
| 377 vim9script | |
| 378 def g:GlobalFunc(): string | |
| 379 return 'text' | |
| 380 enddef | |
| 381 echo GlobalFunc() | |
| 382 The "g:" prefix is not needed for auto-load functions. | |
| 383 | |
| 25619 | 384 *vim9-function-defined-later* |
| 385 Although global functions can be called without the "g:" prefix, they must | |
| 386 exist when compiled. By adding the "g:" prefix the function can be defined | |
| 387 later. Example: > | |
| 388 def CallPluginFunc() | |
| 389 if exists('g:loaded_plugin') | |
| 390 g:PluginFunc() | |
| 391 endif | |
| 392 enddef | |
| 393 | |
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394 If you do it like this, you get an error at compile time that "PluginFunc" |
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395 does not exist, even when "g:loaded_plugin" does not exist: > |
| 25619 | 396 def CallPluginFunc() |
| 397 if exists('g:loaded_plugin') | |
| 398 PluginFunc() # Error - function not found | |
| 399 endif | |
| 400 enddef | |
| 401 | |
| 402 You can use exists_compiled() to avoid the error, but then the function would | |
| 403 not be called, even when "g:loaded_plugin" is defined later: > | |
| 404 def CallPluginFunc() | |
| 405 if exists_compiled('g:loaded_plugin') | |
| 406 PluginFunc() # Function may never be called | |
| 407 endif | |
| 408 enddef | |
| 409 | |
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410 Since `&opt = value` is now assigning a value to option "opt", ":&" cannot be |
|
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411 used to repeat a `:substitute` command. |
| 24468 | 412 *vim9-unpack-ignore* |
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413 For an unpack assignment the underscore can be used to ignore a list item, |
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414 similar to how a function argument can be ignored: > |
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415 [a, _, c] = theList |
| 24468 | 416 To ignore any remaining items: > |
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417 [a, b; _] = longList |
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418 |
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419 Declaring more than one variable at a time, using the unpack notation, is |
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420 possible. Each variable can have a type or infer it from the value: > |
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421 var [v1: number, v2] = GetValues() |
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422 Use this only when there is a list with values, declaring one variable per |
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423 line is much easier to read and change later. |
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424 |
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425 |
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426 Constants ~ |
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427 *vim9-const* *vim9-final* |
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428 How constants work varies between languages. Some consider a variable that |
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429 can't be assigned another value a constant. JavaScript is an example. Others |
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430 also make the value immutable, thus when a constant uses a list, the list |
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431 cannot be changed. In Vim9 we can use both. |
| 27321 | 432 *E1021* |
|
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433 `:const` is used for making both the variable and the value a constant. Use |
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434 this for composite structures that you want to make sure will not be modified. |
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435 Example: > |
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436 const myList = [1, 2] |
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437 myList = [3, 4] # Error! |
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438 myList[0] = 9 # Error! |
| 24024 | 439 myList->add(3) # Error! |
| 27459 | 440 < *:final* *E1125* |
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441 `:final` is used for making only the variable a constant, the value can be |
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442 changed. This is well known from Java. Example: > |
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443 final myList = [1, 2] |
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444 myList = [3, 4] # Error! |
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445 myList[0] = 9 # OK |
| 24024 | 446 myList->add(3) # OK |
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447 |
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448 It is common to write constants as ALL_CAPS, but you don't have to. |
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449 |
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450 The constant only applies to the value itself, not what it refers to. > |
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451 final females = ["Mary"] |
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452 const NAMES = [["John", "Peter"], females] |
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453 NAMES[0] = ["Jack"] # Error! |
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454 NAMES[0][0] = "Jack" # Error! |
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455 NAMES[1] = ["Emma"] # Error! |
| 23573 | 456 NAMES[1][0] = "Emma" # OK, now females[0] == "Emma" |
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457 |
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458 |
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459 Omitting :call and :eval ~ |
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460 |
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461 Functions can be called without `:call`: > |
| 22171 | 462 writefile(lines, 'file') |
| 19303 | 463 Using `:call` is still possible, but this is discouraged. |
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464 |
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465 A method call without `eval` is possible, so long as the start is an |
|
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466 identifier or can't be an Ex command. For a function either "(" or "->" must |
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467 be following, without a line break. Examples: > |
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468 myList->add(123) |
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469 g:myList->add(123) |
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470 [1, 2, 3]->Process() |
|
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patch 8.2.2015: Vim9: literal dict #{} is not like any other language
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|
471 {a: 1, b: 2}->Process() |
|
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|
472 "foobar"->Process() |
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|
473 ("foobar")->Process() |
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474 'foobar'->Process() |
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|
475 ('foobar')->Process() |
|
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patch 8.2.0149: maintaining a Vim9 branch separately is more work
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|
476 |
| 21825 | 477 In the rare case there is ambiguity between a function name and an Ex command, |
| 21676 | 478 prepend ":" to make clear you want to use the Ex command. For example, there |
| 479 is both the `:substitute` command and the `substitute()` function. When the | |
| 480 line starts with `substitute(` this will use the function. Prepend a colon to | |
| 481 use the command instead: > | |
|
19481
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patch 8.2.0298: Vim9 script: cannot start command with a string constant
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|
482 :substitute(pattern (replacement ( |
|
19473
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patch 8.2.0294: cannot use Ex command that is also a function name
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|
483 |
| 25402 | 484 If the expression starts with "!" this is interpreted as a shell command, not |
| 485 negation of a condition. Thus this is a shell command: > | |
| 486 !shellCommand->something | |
| 25700 | 487 Put the expression in parentheses to use the "!" for negation: > |
| 25402 | 488 (!expression)->Method() |
| 489 | |
|
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patch 8.2.0335: no completion for :disassemble
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490 Note that while variables need to be defined before they can be used, |
| 21825 | 491 functions can be called before being defined. This is required to allow |
| 492 for cyclic dependencies between functions. It is slightly less efficient, | |
|
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patch 8.2.0335: no completion for :disassemble
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|
493 since the function has to be looked up by name. And a typo in the function |
|
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494 name will only be found when the function is called. |
|
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Bram Moolenaar <Bram@vim.org>
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|
495 |
|
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|
496 |
| 19968 | 497 Omitting function() ~ |
| 498 | |
| 499 A user defined function can be used as a function reference in an expression | |
| 500 without `function()`. The argument types and return type will then be checked. | |
| 501 The function must already have been defined. > | |
| 502 | |
|
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|
503 var Funcref = MyFunction |
| 19968 | 504 |
| 505 When using `function()` the resulting type is "func", a function with any | |
| 25161 | 506 number of arguments and any return type (including void). The function can be |
| 26708 | 507 defined later if the argument is in quotes. |
| 19968 | 508 |
| 509 | |
|
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changeset
|
510 Lambda using => instead of -> ~ |
| 24387 | 511 *vim9-lambda* |
|
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patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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changeset
|
512 In legacy script there can be confusion between using "->" for a method call |
|
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513 and for a lambda. Also, when a "{" is found the parser needs to figure out if |
|
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
514 it is the start of a lambda or a dictionary, which is now more complicated |
|
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|
515 because of the use of argument types. |
|
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|
516 |
|
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
517 To avoid these problems Vim9 script uses a different syntax for a lambda, |
|
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patch 8.2.2982: Vim9: future commands are not reserved yet
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|
518 which is similar to JavaScript: > |
|
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patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
519 var Lambda = (arg) => expression |
|
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|
520 |
|
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Bram Moolenaar <Bram@vim.org>
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|
521 No line break is allowed in the arguments of a lambda up to and including the |
| 25056 | 522 "=>" (so that Vim can tell the difference between an expression in parentheses |
| 24911 | 523 and lambda arguments). This is OK: > |
|
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Bram Moolenaar <Bram@vim.org>
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|
524 filter(list, (k, v) => |
|
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
525 v > 0) |
|
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Bram Moolenaar <Bram@vim.org>
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|
526 This does not work: > |
|
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patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
Bram Moolenaar <Bram@vim.org>
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527 filter(list, (k, v) |
|
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patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
528 => v > 0) |
|
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Bram Moolenaar <Bram@vim.org>
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|
529 This also does not work: > |
|
23318
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Bram Moolenaar <Bram@vim.org>
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|
530 filter(list, (k, |
|
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
531 v) => v > 0) |
|
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532 But you can use a backslash to concatenate the lines before parsing: > |
|
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
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|
533 filter(list, (k, |
|
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534 \ v) |
|
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Bram Moolenaar <Bram@vim.org>
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|
535 \ => v > 0) |
|
24408
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patch 8.2.2744: Vim9: no way to explicitly ignore an argument
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changeset
|
536 < *vim9-lambda-arguments* |
|
96e0b898d5b4
patch 8.2.2744: Vim9: no way to explicitly ignore an argument
Bram Moolenaar <Bram@vim.org>
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|
537 In legacy script a lambda could be called with any number of extra arguments, |
|
96e0b898d5b4
patch 8.2.2744: Vim9: no way to explicitly ignore an argument
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changeset
|
538 there was no way to warn for not using them. In Vim9 script the number of |
|
96e0b898d5b4
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Bram Moolenaar <Bram@vim.org>
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|
539 arguments must match. If you do want to accept any arguments, or any further |
|
96e0b898d5b4
patch 8.2.2744: Vim9: no way to explicitly ignore an argument
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changeset
|
540 arguments, use "..._", which makes the function accept |
|
96e0b898d5b4
patch 8.2.2744: Vim9: no way to explicitly ignore an argument
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|
541 |vim9-variable-arguments|. Example: > |
|
96e0b898d5b4
patch 8.2.2744: Vim9: no way to explicitly ignore an argument
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|
542 var Callback = (..._) => 'anything' |
|
96e0b898d5b4
patch 8.2.2744: Vim9: no way to explicitly ignore an argument
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|
543 echo Callback(1, 2, 3) # displays "anything" |
|
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patch 8.2.2744: Vim9: no way to explicitly ignore an argument
Bram Moolenaar <Bram@vim.org>
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|
544 |
| 24387 | 545 < *inline-function* |
|
23318
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patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
546 Additionally, a lambda can contain statements in {}: > |
|
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
Bram Moolenaar <Bram@vim.org>
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|
547 var Lambda = (arg) => { |
|
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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|
548 g:was_called = 'yes' |
|
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
Bram Moolenaar <Bram@vim.org>
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|
549 return expression |
|
c76240efdf02
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Bram Moolenaar <Bram@vim.org>
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|
550 } |
| 24387 | 551 This can be useful for a timer, for example: > |
| 552 var count = 0 | |
| 553 var timer = timer_start(500, (_) => { | |
| 554 count += 1 | |
| 555 echom 'Handler called ' .. count | |
| 556 }, {repeat: 3}) | |
| 557 | |
|
24272
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
parents:
24150
diff
changeset
|
558 The ending "}" must be at the start of a line. It can be followed by other |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
559 characters, e.g.: > |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
560 var d = mapnew(dict, (k, v): string => { |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
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changeset
|
561 return 'value' |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
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changeset
|
562 }) |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
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parents:
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changeset
|
563 No command can follow the "{", only a comment can be used there. |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
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changeset
|
564 |
| 27321 | 565 *command-block* *E1026* |
|
26612
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patch 8.2.3835: the inline-function example does not work
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
566 The block can also be used for defining a user command. Inside the block Vim9 |
|
2586659245db
patch 8.2.3835: the inline-function example does not work
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
567 syntax will be used. |
|
2586659245db
patch 8.2.3835: the inline-function example does not work
Bram Moolenaar <Bram@vim.org>
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changeset
|
568 |
| 26591 | 569 If the statements include a dictionary, its closing bracket must not be |
| 570 written at the start of a line. Otherwise, it would be parsed as the end of | |
| 571 the block. This does not work: > | |
| 572 command NewCommand { | |
|
26612
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patch 8.2.3835: the inline-function example does not work
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changeset
|
573 g:mydict = { |
| 26591 | 574 'key': 'value', |
| 575 } # ERROR: will be recognized as the end of the block | |
| 576 } | |
| 577 Put the '}' after the last item to avoid this: > | |
| 578 command NewCommand { | |
|
26612
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patch 8.2.3835: the inline-function example does not work
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changeset
|
579 g:mydict = { |
| 26591 | 580 'key': 'value' } |
| 581 } | |
| 582 | |
|
24272
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patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
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changeset
|
583 Rationale: The "}" cannot be after a command because it would require parsing |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
584 the commands to find it. For consistency with that no command can follow the |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
585 "{". Unfortunately this means using "() => { command }" does not work, line |
|
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
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changeset
|
586 breaks are always required. |
|
23318
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Bram Moolenaar <Bram@vim.org>
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changeset
|
587 |
| 23737 | 588 *vim9-curly* |
|
23358
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changeset
|
589 To avoid the "{" of a dictionary literal to be recognized as a statement block |
| 24024 | 590 wrap it in parentheses: > |
|
23358
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patch 8.2.2222: Vim9: cannot keep script variables when reloading
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changeset
|
591 var Lambda = (arg) => ({key: 42}) |
|
23318
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patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
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changeset
|
592 |
| 23737 | 593 Also when confused with the start of a command block: > |
| 594 ({ | |
| 595 key: value | |
| 596 })->method() | |
| 597 | |
|
23318
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patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
Bram Moolenaar <Bram@vim.org>
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changeset
|
598 |
|
19999
844c7646f61b
patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
parents:
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changeset
|
599 Automatic line continuation ~ |
| 27459 | 600 *vim9-line-continuation* *E1097* |
|
19999
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patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
601 In many cases it is obvious that an expression continues on the next line. In |
|
23392
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
602 those cases there is no need to prefix the line with a backslash (see |
|
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
603 |line-continuation|). For example, when a list spans multiple lines: > |
|
22391
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patch 8.2.1744: Vim9: using ":const!" is weird
Bram Moolenaar <Bram@vim.org>
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changeset
|
604 var mylist = [ |
|
19999
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patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
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changeset
|
605 'one', |
|
844c7646f61b
patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
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changeset
|
606 'two', |
|
844c7646f61b
patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
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changeset
|
607 ] |
|
20011
628011800942
patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
parents:
19999
diff
changeset
|
608 And when a dict spans multiple lines: > |
|
22936
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patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
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changeset
|
609 var mydict = { |
|
20011
628011800942
patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
610 one: 1, |
|
628011800942
patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
611 two: 2, |
|
628011800942
patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
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changeset
|
612 } |
|
24888
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
613 With a function call: > |
|
22391
a9fb7efa31d6
patch 8.2.1744: Vim9: using ":const!" is weird
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
614 var result = Func( |
|
20011
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patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
615 arg1, |
|
628011800942
patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
616 arg2 |
|
628011800942
patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
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|
617 ) |
|
628011800942
patch 8.2.0561: Vim9: cannot split function call in multiple lines
Bram Moolenaar <Bram@vim.org>
parents:
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|
618 |
|
20982
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patch 8.2.1042: Vim9: cannot put an operator on the next line
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changeset
|
619 For binary operators in expressions not in [], {} or () a line break is |
|
bb49b5090a9c
patch 8.2.1042: Vim9: cannot put an operator on the next line
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parents:
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|
620 possible just before or after the operator. For example: > |
|
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patch 8.2.1744: Vim9: using ":const!" is weird
Bram Moolenaar <Bram@vim.org>
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|
621 var text = lead |
|
20982
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patch 8.2.1042: Vim9: cannot put an operator on the next line
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|
622 .. middle |
|
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patch 8.2.1042: Vim9: cannot put an operator on the next line
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|
623 .. end |
|
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patch 8.2.1744: Vim9: using ":const!" is weird
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|
624 var total = start + |
| 23573 | 625 end - |
|
20013
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patch 8.2.0562: Vim9: cannot split an expression into multiple lines
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changeset
|
626 correction |
|
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|
627 var result = positive |
|
20982
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patch 8.2.1042: Vim9: cannot put an operator on the next line
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|
628 ? PosFunc(arg) |
|
bb49b5090a9c
patch 8.2.1042: Vim9: cannot put an operator on the next line
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|
629 : NegFunc(arg) |
|
20013
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patch 8.2.0562: Vim9: cannot split an expression into multiple lines
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changeset
|
630 |
| 21499 | 631 For a method call using "->" and a member using a dot, a line break is allowed |
| 632 before it: > | |
|
22391
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patch 8.2.1744: Vim9: using ":const!" is weird
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|
633 var result = GetBuilder() |
| 20965 | 634 ->BuilderSetWidth(333) |
| 635 ->BuilderSetHeight(777) | |
| 636 ->BuilderBuild() | |
|
22391
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changeset
|
637 var result = MyDict |
| 21499 | 638 .member |
| 20965 | 639 |
|
23392
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
Bram Moolenaar <Bram@vim.org>
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changeset
|
640 For commands that have an argument that is a list of commands, the | character |
|
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
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parents:
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changeset
|
641 at the start of the line indicates line continuation: > |
|
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
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|
642 autocmd BufNewFile *.match if condition |
|
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
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|
643 | echo 'match' |
|
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patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
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644 | endif |
|
517fca70e084
patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
Bram Moolenaar <Bram@vim.org>
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changeset
|
645 |
| 25973 | 646 Note that this means that in heredoc the first line cannot start with a bar: > |
|
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patch 8.2.2982: Vim9: future commands are not reserved yet
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parents:
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|
647 var lines =<< trim END |
|
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patch 8.2.2982: Vim9: future commands are not reserved yet
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|
648 | this doesn't work |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
Bram Moolenaar <Bram@vim.org>
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|
649 END |
|
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patch 8.2.2982: Vim9: future commands are not reserved yet
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diff
changeset
|
650 Either use an empty line at the start or do not use heredoc. Or temporarily |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
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diff
changeset
|
651 add the "C" flag to 'cpoptions': > |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
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changeset
|
652 set cpo+=C |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
Bram Moolenaar <Bram@vim.org>
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changeset
|
653 var lines =<< trim END |
| 25973 | 654 | this works |
|
24888
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|
655 END |
|
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patch 8.2.2982: Vim9: future commands are not reserved yet
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changeset
|
656 set cpo-=C |
|
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changeset
|
657 If the heredoc is inside a function 'cpoptions' must be set before :def and |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
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changeset
|
658 restored after the :enddef. |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
Bram Moolenaar <Bram@vim.org>
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changeset
|
659 |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
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changeset
|
660 In places where line continuation with a backslash is still needed, such as |
| 25161 | 661 splitting up a long Ex command, comments can start with '#\ ': > |
| 662 syn region Text | |
|
24888
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patch 8.2.2982: Vim9: future commands are not reserved yet
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changeset
|
663 \ start='foo' |
|
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|
664 #\ comment |
|
b6ac4ed5e2d2
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|
665 \ end='bar' |
| 25161 | 666 Like with legacy script '"\ ' is used. This is also needed when line |
| 667 continuation is used without a backslash and a line starts with a bar: > | |
| 668 au CursorHold * echom 'BEFORE bar' | |
| 669 #\ some comment | |
| 670 | echom 'AFTER bar' | |
| 671 < | |
| 672 *E1050* | |
|
20982
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patch 8.2.1042: Vim9: cannot put an operator on the next line
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parents:
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changeset
|
673 To make it possible for the operator at the start of the line to be |
|
24888
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|
674 recognized, it is required to put a colon before a range. This example will |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
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changeset
|
675 add "start" and print: > |
|
22391
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patch 8.2.1744: Vim9: using ":const!" is weird
Bram Moolenaar <Bram@vim.org>
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|
676 var result = start |
|
20982
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patch 8.2.1042: Vim9: cannot put an operator on the next line
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changeset
|
677 + print |
| 21250 | 678 Like this: > |
|
22391
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Bram Moolenaar <Bram@vim.org>
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changeset
|
679 var result = start + print |
| 21250 | 680 |
|
20982
bb49b5090a9c
patch 8.2.1042: Vim9: cannot put an operator on the next line
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
681 This will assign "start" and print a line: > |
|
22391
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Bram Moolenaar <Bram@vim.org>
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changeset
|
682 var result = start |
|
20982
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patch 8.2.1042: Vim9: cannot put an operator on the next line
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
683 :+ print |
|
19999
844c7646f61b
patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
parents:
19968
diff
changeset
|
684 |
| 27321 | 685 After the range an Ex command must follow. Without the colon you can call a |
| 686 function without `:call`, but after a range you do need it: > | |
| 687 MyFunc() | |
| 688 :% call MyFunc() | |
| 689 | |
| 23047 | 690 Note that the colon is not required for the |+cmd| argument: > |
| 691 edit +6 fname | |
| 692 | |
|
20015
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
parents:
20013
diff
changeset
|
693 It is also possible to split a function header over multiple lines, in between |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
694 arguments: > |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
parents:
20013
diff
changeset
|
695 def MyFunc( |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
parents:
20013
diff
changeset
|
696 text: string, |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
697 separator = '-' |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
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changeset
|
698 ): string |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
699 |
| 23305 | 700 Since a continuation line cannot be easily recognized the parsing of commands |
|
23318
c76240efdf02
patch 8.2.2204: Vim9: using -> both for method and lambda is confusing
Bram Moolenaar <Bram@vim.org>
parents:
23305
diff
changeset
|
701 has been made stricter. E.g., because of the error in the first line, the |
| 23305 | 702 second line is seen as a separate command: > |
| 703 popup_create(some invalid expression, { | |
| 704 exit_cb: Func}) | |
| 705 Now "exit_cb: Func})" is actually a valid command: save any changes to the | |
| 706 file "_cb: Func})" and exit. To avoid this kind of mistake in Vim9 script | |
| 707 there must be white space between most command names and the argument. | |
| 27459 | 708 *E1144* |
| 23305 | 709 |
| 23666 | 710 However, the argument of a command that is a command won't be recognized. For |
| 711 example, after "windo echo expr" a line break inside "expr" will not be seen. | |
| 712 | |
| 23305 | 713 |
| 21250 | 714 Notes: |
| 715 - "enddef" cannot be used at the start of a continuation line, it ends the | |
| 716 current function. | |
| 717 - No line break is allowed in the LHS of an assignment. Specifically when | |
| 718 unpacking a list |:let-unpack|. This is OK: > | |
| 22171 | 719 [var1, var2] = |
| 21250 | 720 Func() |
| 721 < This does not work: > | |
| 22171 | 722 [var1, |
| 21250 | 723 var2] = |
| 724 Func() | |
| 725 - No line break is allowed in between arguments of an `:echo`, `:execute` and | |
| 726 similar commands. This is OK: > | |
| 22171 | 727 echo [1, |
| 21250 | 728 2] [3, |
| 729 4] | |
| 730 < This does not work: > | |
| 22171 | 731 echo [1, 2] |
| 21250 | 732 [3, 4] |
|
24888
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
733 - In some cases it is difficult for Vim to parse a command, especially when |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
734 commands are used as an argument to another command, such as `windo`. In |
|
b6ac4ed5e2d2
patch 8.2.2982: Vim9: future commands are not reserved yet
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
735 those cases the line continuation with a backslash has to be used. |
|
19999
844c7646f61b
patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
736 |
| 24569 | 737 |
| 738 White space ~ | |
| 27459 | 739 *E1004* *E1068* *E1069* *E1074* *E1127* |
| 24569 | 740 Vim9 script enforces proper use of white space. This is no longer allowed: > |
| 741 var name=234 # Error! | |
| 742 var name= 234 # Error! | |
| 743 var name =234 # Error! | |
| 744 There must be white space before and after the "=": > | |
| 745 var name = 234 # OK | |
| 746 White space must also be put before the # that starts a comment after a | |
| 747 command: > | |
| 748 var name = 234# Error! | |
| 749 var name = 234 # OK | |
| 750 | |
| 751 White space is required around most operators. | |
| 752 | |
| 753 White space is required in a sublist (list slice) around the ":", except at | |
| 754 the start and end: > | |
| 755 otherlist = mylist[v : count] # v:count has a different meaning | |
| 756 otherlist = mylist[:] # make a copy of the List | |
| 757 otherlist = mylist[v :] | |
| 758 otherlist = mylist[: v] | |
| 759 | |
| 760 White space is not allowed: | |
| 761 - Between a function name and the "(": > | |
| 762 Func (arg) # Error! | |
| 763 Func | |
| 764 \ (arg) # Error! | |
| 765 Func | |
| 766 (arg) # Error! | |
| 767 Func(arg) # OK | |
| 768 Func( | |
| 769 arg) # OK | |
| 770 Func( | |
| 771 arg # OK | |
| 772 ) | |
| 773 | |
| 25700 | 774 White space is not allowed in a `:set` command between the option name and a |
| 775 following "&", "!", "<", "=", "+=", "-=" or "^=". | |
| 25402 | 776 |
| 24569 | 777 |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
778 No curly braces expansion ~ |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
779 |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
780 |curly-braces-names| cannot be used. |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
781 |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
782 |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
783 Dictionary literals ~ |
| 27321 | 784 *vim9-literal-dict* *E1014* |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
785 Traditionally Vim has supported dictionary literals with a {} syntax: > |
|
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
786 let dict = {'key': value} |
|
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
787 |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
788 Later it became clear that using a simple text key is very common, thus |
|
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
789 literal dictionaries were introduced in a backwards compatible way: > |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
790 let dict = #{key: value} |
|
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
791 |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
792 However, this #{} syntax is unlike any existing language. As it turns out |
|
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
793 that using a literal key is much more common than using an expression, and |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
794 considering that JavaScript uses this syntax, using the {} form for dictionary |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
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diff
changeset
|
795 literals is considered a much more useful syntax. In Vim9 script the {} form |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
796 uses literal keys: > |
| 23666 | 797 var dict = {key: value} |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
798 |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
799 This works for alphanumeric characters, underscore and dash. If you want to |
|
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
800 use another character, use a single or double quoted string: > |
| 23666 | 801 var dict = {'key with space': value} |
| 802 var dict = {"key\twith\ttabs": value} | |
| 803 var dict = {'': value} # empty key | |
| 27459 | 804 < *E1139* |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
805 In case the key needs to be an expression, square brackets can be used, just |
|
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
806 like in JavaScript: > |
| 23666 | 807 var dict = {["key" .. nr]: value} |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
808 |
|
23827
7e0d8f1cae7d
patch 8.2.2455: Vim9: key type for literal dict and indexing is inconsistent
Bram Moolenaar <Bram@vim.org>
parents:
23737
diff
changeset
|
809 The key type can be string, number, bool or float. Other types result in an |
|
7e0d8f1cae7d
patch 8.2.2455: Vim9: key type for literal dict and indexing is inconsistent
Bram Moolenaar <Bram@vim.org>
parents:
23737
diff
changeset
|
810 error. A number can be given with and without the []: > |
|
7e0d8f1cae7d
patch 8.2.2455: Vim9: key type for literal dict and indexing is inconsistent
Bram Moolenaar <Bram@vim.org>
parents:
23737
diff
changeset
|
811 var dict = {123: 'without', [456]: 'with'} |
|
7e0d8f1cae7d
patch 8.2.2455: Vim9: key type for literal dict and indexing is inconsistent
Bram Moolenaar <Bram@vim.org>
parents:
23737
diff
changeset
|
812 echo dict |
|
7e0d8f1cae7d
patch 8.2.2455: Vim9: key type for literal dict and indexing is inconsistent
Bram Moolenaar <Bram@vim.org>
parents:
23737
diff
changeset
|
813 {'456': 'with', '123': 'without'} |
|
7e0d8f1cae7d
patch 8.2.2455: Vim9: key type for literal dict and indexing is inconsistent
Bram Moolenaar <Bram@vim.org>
parents:
23737
diff
changeset
|
814 |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
815 |
|
23978
54b2aa1f0d42
patch 8.2.2531: Vim9: the :k command is obscure
Bram Moolenaar <Bram@vim.org>
parents:
23974
diff
changeset
|
816 No :xit, :t, :k, :append, :change or :insert ~ |
| 27459 | 817 *E1100* |
|
21584
d0c76ce48326
patch 8.2.1342: Vim9: accidentally using "t" gives a confusing error
Bram Moolenaar <Bram@vim.org>
parents:
21550
diff
changeset
|
818 These commands are too easily confused with local variable names. |
|
d0c76ce48326
patch 8.2.1342: Vim9: accidentally using "t" gives a confusing error
Bram Moolenaar <Bram@vim.org>
parents:
21550
diff
changeset
|
819 Instead of `:x` or `:xit` you can use `:exit`. |
|
d0c76ce48326
patch 8.2.1342: Vim9: accidentally using "t" gives a confusing error
Bram Moolenaar <Bram@vim.org>
parents:
21550
diff
changeset
|
820 Instead of `:t` you can use `:copy`. |
|
23978
54b2aa1f0d42
patch 8.2.2531: Vim9: the :k command is obscure
Bram Moolenaar <Bram@vim.org>
parents:
23974
diff
changeset
|
821 Instead of `:k` you can use `:mark`. |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
822 |
| 19303 | 823 |
| 824 Comparators ~ | |
| 825 | |
| 826 The 'ignorecase' option is not used for comparators that use strings. | |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
827 |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
828 |
| 24569 | 829 Abort after error ~ |
| 830 | |
| 831 In legacy script, when an error is encountered, Vim continues to execute | |
| 832 following lines. This can lead to a long sequence of errors and need to type | |
| 833 CTRL-C to stop it. In Vim9 script execution of commands stops at the first | |
| 834 error. Example: > | |
| 835 vim9script | |
| 836 var x = does-not-exist | |
| 837 echo 'not executed' | |
| 838 | |
| 839 | |
| 23666 | 840 For loop ~ |
| 841 | |
| 26438 | 842 The loop variable must not be declared yet: > |
| 26304 | 843 var i = 1 |
| 844 for i in [1, 2, 3] # Error! | |
| 845 | |
| 26438 | 846 It is possible to use a global variable though: > |
| 847 g:i = 1 | |
| 848 for g:i in [1, 2, 3] | |
| 849 echo g:i | |
| 850 endfor | |
| 851 | |
| 23666 | 852 Legacy Vim script has some tricks to make a for loop over a list handle |
| 853 deleting items at the current or previous item. In Vim9 script it just uses | |
| 854 the index, if items are deleted then items in the list will be skipped. | |
| 855 Example legacy script: > | |
| 856 let l = [1, 2, 3, 4] | |
| 857 for i in l | |
| 858 echo i | |
| 859 call remove(l, index(l, i)) | |
| 860 endfor | |
| 861 Would echo: | |
| 862 1 | |
| 863 2 | |
| 864 3 | |
| 865 4 | |
| 866 In compiled Vim9 script you get: | |
| 867 1 | |
| 868 3 | |
| 869 Generally, you should not change the list that is iterated over. Make a copy | |
| 870 first if needed. | |
| 871 | |
| 872 | |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
873 Conditions and expressions ~ |
| 27321 | 874 *vim9-boolean* |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
875 Conditions and expressions are mostly working like they do in other languages. |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
876 Some values are different from legacy Vim script: |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
877 value legacy Vim script Vim9 script ~ |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
878 0 falsy falsy |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
879 1 truthy truthy |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
880 99 truthy Error! |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
881 "0" falsy Error! |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
882 "99" truthy Error! |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
883 "text" falsy Error! |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
884 |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
885 For the "??" operator and when using "!" then there is no error, every value |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
886 is either falsy or truthy. This is mostly like JavaScript, except that an |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
887 empty list and dict is falsy: |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
888 |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
889 type truthy when ~ |
| 23466 | 890 bool true, v:true or 1 |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
891 number non-zero |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
892 float non-zero |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
893 string non-empty |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
894 blob non-empty |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
895 list non-empty (different from JavaScript) |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
896 dictionary non-empty (different from JavaScript) |
| 19968 | 897 func when there is a function name |
| 23466 | 898 special true or v:true |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
899 job when not NULL |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
900 channel when not NULL |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
901 class when not NULL |
| 23466 | 902 object when not NULL (TODO: when isTrue() returns true) |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
903 |
|
22494
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
904 The boolean operators "||" and "&&" expect the values to be boolean, zero or |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
905 one: > |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
906 1 || false == true |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
907 0 || 1 == true |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
908 0 || false == false |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
909 1 && true == true |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
910 0 && 1 == false |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
911 8 || 0 Error! |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
912 'yes' && 0 Error! |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
913 [] || 99 Error! |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
914 |
|
22494
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
915 When using "!" for inverting, there is no error for using any type and the |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
916 result is a boolean. "!!" can be used to turn any value into boolean: > |
| 23573 | 917 !'yes' == false |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
918 !![] == false |
| 23573 | 919 !![1, 2, 3] == true |
|
22494
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
920 |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
921 When using "`.."` for string concatenation arguments of simple types are |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
922 always converted to string: > |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
923 'hello ' .. 123 == 'hello 123' |
| 23466 | 924 'hello ' .. v:true == 'hello true' |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
925 |
|
26769
30972227ac8d
patch 8.2.3913: help for expressions does not mention Vim9 syntax
Bram Moolenaar <Bram@vim.org>
parents:
26755
diff
changeset
|
926 Simple types are Number, Float, Special and Bool. For other types |string()| |
|
30972227ac8d
patch 8.2.3913: help for expressions does not mention Vim9 syntax
Bram Moolenaar <Bram@vim.org>
parents:
26755
diff
changeset
|
927 should be used. |
| 27321 | 928 *false* *true* *null* *E1034* |
|
23497
2247a2ce3630
patch 8.2.2291: Vim9: cannot use "null" for v:null
Bram Moolenaar <Bram@vim.org>
parents:
23466
diff
changeset
|
929 In Vim9 script one can use "true" for v:true, "false" for v:false and "null" |
|
2247a2ce3630
patch 8.2.2291: Vim9: cannot use "null" for v:null
Bram Moolenaar <Bram@vim.org>
parents:
23466
diff
changeset
|
930 for v:null. When converting a boolean to a string "false" and "true" are |
|
2247a2ce3630
patch 8.2.2291: Vim9: cannot use "null" for v:null
Bram Moolenaar <Bram@vim.org>
parents:
23466
diff
changeset
|
931 used, not "v:false" and "v:true" like in legacy script. "v:none" is not |
|
2247a2ce3630
patch 8.2.2291: Vim9: cannot use "null" for v:null
Bram Moolenaar <Bram@vim.org>
parents:
23466
diff
changeset
|
932 changed, it is only used in JSON and has no equivalent in other languages. |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
933 |
|
24128
fcbb1d4df15b
patch 8.2.2605: Vim9: string index and slice does not include composing chars
Bram Moolenaar <Bram@vim.org>
parents:
24103
diff
changeset
|
934 Indexing a string with [idx] or taking a slice with [idx : idx] uses character |
|
fcbb1d4df15b
patch 8.2.2605: Vim9: string index and slice does not include composing chars
Bram Moolenaar <Bram@vim.org>
parents:
24103
diff
changeset
|
935 indexes instead of byte indexes. Composing characters are included. |
|
fcbb1d4df15b
patch 8.2.2605: Vim9: string index and slice does not include composing chars
Bram Moolenaar <Bram@vim.org>
parents:
24103
diff
changeset
|
936 Example: > |
| 21825 | 937 echo 'bár'[1] |
| 938 In legacy script this results in the character 0xc3 (an illegal byte), in Vim9 | |
| 939 script this results in the string 'á'. | |
| 23573 | 940 A negative index is counting from the end, "[-1]" is the last character. |
| 23666 | 941 To exclude the last character use |slice()|. |
|
24272
cabed216cc2f
patch 8.2.2677: Vim9: cannot use only some of the default arguments
Bram Moolenaar <Bram@vim.org>
parents:
24150
diff
changeset
|
942 To count composing characters separately use |strcharpart()|. |
| 23573 | 943 If the index is out of range then an empty string results. |
| 944 | |
| 945 In legacy script "++var" and "--var" would be silently accepted and have no | |
| 946 effect. This is an error in Vim9 script. | |
| 947 | |
| 948 Numbers starting with zero are not considered to be octal, only numbers | |
| 949 starting with "0o" are octal: "0o744". |scriptversion-4| | |
| 21825 | 950 |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
951 |
| 21093 | 952 What to watch out for ~ |
| 953 *vim9-gotchas* | |
| 954 Vim9 was designed to be closer to often used programming languages, but at the | |
| 955 same time tries to support the legacy Vim commands. Some compromises had to | |
| 956 be made. Here is a summary of what might be unexpected. | |
| 957 | |
| 958 Ex command ranges need to be prefixed with a colon. > | |
| 23666 | 959 -> legacy Vim: shifts the previous line to the right |
| 960 ->func() Vim9: method call in a continuation line | |
| 961 :-> Vim9: shifts the previous line to the right | |
| 21093 | 962 |
| 23666 | 963 %s/a/b legacy Vim: substitute on all lines |
| 21093 | 964 x = alongname |
| 23666 | 965 % another Vim9: modulo operator in a continuation line |
| 966 :%s/a/b Vim9: substitute on all lines | |
| 967 't legacy Vim: jump to mark t | |
| 968 'text'->func() Vim9: method call | |
| 969 :'t Vim9: jump to mark t | |
| 21093 | 970 |
| 21676 | 971 Some Ex commands can be confused with assignments in Vim9 script: > |
| 23666 | 972 g:name = value # assignment |
|
25939
377a7686a52f
patch 8.2.3503: Vim9: using g:pat:cmd is confusing
Bram Moolenaar <Bram@vim.org>
parents:
25836
diff
changeset
|
973 :g:pattern:cmd # :global command |
|
377a7686a52f
patch 8.2.3503: Vim9: using g:pat:cmd is confusing
Bram Moolenaar <Bram@vim.org>
parents:
25836
diff
changeset
|
974 |
|
377a7686a52f
patch 8.2.3503: Vim9: using g:pat:cmd is confusing
Bram Moolenaar <Bram@vim.org>
parents:
25836
diff
changeset
|
975 To avoid confusion between a `:global` or `:substitute` command and an |
|
377a7686a52f
patch 8.2.3503: Vim9: using g:pat:cmd is confusing
Bram Moolenaar <Bram@vim.org>
parents:
25836
diff
changeset
|
976 expression or assignment, a few separators cannot be used when these commands |
|
377a7686a52f
patch 8.2.3503: Vim9: using g:pat:cmd is confusing
Bram Moolenaar <Bram@vim.org>
parents:
25836
diff
changeset
|
977 are abbreviated to a single character: ':', '-' and '.'. > |
| 23666 | 978 g:pattern:cmd # invalid command - ERROR |
|
25939
377a7686a52f
patch 8.2.3503: Vim9: using g:pat:cmd is confusing
Bram Moolenaar <Bram@vim.org>
parents:
25836
diff
changeset
|
979 s:pattern:repl # invalid command - ERROR |
|
377a7686a52f
patch 8.2.3503: Vim9: using g:pat:cmd is confusing
Bram Moolenaar <Bram@vim.org>
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980 g-pattern-cmd # invalid command - ERROR |
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981 s-pattern-repl # invalid command - ERROR |
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982 g.pattern.cmd # invalid command - ERROR |
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983 s.pattern.repl # invalid command - ERROR |
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984 |
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985 Also, there cannot be a space between the command and the separator: > |
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986 g /pattern/cmd # invalid command - ERROR |
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987 s /pattern/repl # invalid command - ERROR |
| 21676 | 988 |
| 21093 | 989 Functions defined with `:def` compile the whole function. Legacy functions |
| 990 can bail out, and the following lines are not parsed: > | |
| 991 func Maybe() | |
| 992 if !has('feature') | |
| 993 return | |
| 994 endif | |
| 995 use-feature | |
| 996 endfunc | |
| 997 Vim9 functions are compiled as a whole: > | |
| 998 def Maybe() | |
| 999 if !has('feature') | |
| 1000 return | |
| 1001 endif | |
| 23573 | 1002 use-feature # May give a compilation error |
| 21093 | 1003 enddef |
| 1004 For a workaround, split it in two functions: > | |
| 1005 func Maybe() | |
| 1006 if has('feature') | |
| 23666 | 1007 call MaybeInner() |
| 21093 | 1008 endif |
| 1009 endfunc | |
| 1010 if has('feature') | |
| 1011 def MaybeInner() | |
| 1012 use-feature | |
| 1013 enddef | |
| 1014 endif | |
| 22171 | 1015 Or put the unsupported code inside an `if` with a constant expression that |
| 21991 | 1016 evaluates to false: > |
| 1017 def Maybe() | |
| 1018 if has('feature') | |
| 1019 use-feature | |
| 1020 endif | |
| 1021 enddef | |
| 25619 | 1022 The `exists_compiled()` function can also be used for this. |
| 1023 *vim9-user-command* | |
| 23666 | 1024 Another side effect of compiling a function is that the presence of a user |
| 23573 | 1025 command is checked at compile time. If the user command is defined later an |
| 1026 error will result. This works: > | |
| 1027 command -nargs=1 MyCommand echom <q-args> | |
| 1028 def Works() | |
| 1029 MyCommand 123 | |
| 1030 enddef | |
| 1031 This will give an error for "MyCommand" not being defined: > | |
| 1032 def Works() | |
| 1033 command -nargs=1 MyCommand echom <q-args> | |
| 1034 MyCommand 123 | |
| 1035 enddef | |
| 1036 A workaround is to invoke the command indirectly with `:execute`: > | |
| 1037 def Works() | |
| 1038 command -nargs=1 MyCommand echom <q-args> | |
| 1039 execute 'MyCommand 123' | |
| 1040 enddef | |
| 1041 | |
| 21991 | 1042 Note that for unrecognized commands there is no check for "|" and a following |
| 1043 command. This will give an error for missing `endif`: > | |
| 1044 def Maybe() | |
| 1045 if has('feature') | use-feature | endif | |
| 1046 enddef | |
| 21093 | 1047 |
| 23305 | 1048 Other differences ~ |
| 1049 | |
| 1050 Patterns are used like 'magic' is set, unless explicitly overruled. | |
| 1051 The 'edcompatible' option value is not used. | |
| 1052 The 'gdefault' option value is not used. | |
| 1053 | |
| 24387 | 1054 You may also find this wiki useful. It was written by an early adopter of |
| 24103 | 1055 Vim9 script: https://github.com/lacygoill/wiki/blob/master/vim/vim9.md |
| 23305 | 1056 |
| 25056 | 1057 *:++* *:--* |
| 1058 The ++ and -- commands have been added. They are very similar to adding or | |
| 1059 subtracting one: > | |
| 1060 ++var | |
| 1061 var += 1 | |
| 1062 --var | |
| 1063 var -= 1 | |
| 1064 | |
| 1065 Using ++var or --var in an expression is not supported yet. | |
| 1066 | |
|
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1067 ============================================================================== |
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1068 |
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1069 3. New style functions *fast-functions* |
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1070 |
| 27321 | 1071 *:def* *E1028* |
| 21825 | 1072 :def[!] {name}([arguments])[: {return-type}] |
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1073 Define a new function by the name {name}. The body of |
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1074 the function follows in the next lines, until the |
| 27321 | 1075 matching `:enddef`. *E1073* |
| 1076 *E1011* | |
| 1077 The {name} must be less than 100 bytes long. | |
| 1078 *E1003* *E1027* *E1056* *E1059* | |
| 1079 The type of value used with `:return` must match | |
| 1080 {return-type}. When {return-type} is omitted or is | |
| 1081 "void" the function is not expected to return | |
| 1082 anything. | |
| 27459 | 1083 *E1077* *E1123* |
|
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1084 {arguments} is a sequence of zero or more argument |
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1085 declarations. There are three forms: |
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1086 {name}: {type} |
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1087 {name} = {value} |
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1088 {name}: {type} = {value} |
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1089 The first form is a mandatory argument, the caller |
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1090 must always provide them. |
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1091 The second and third form are optional arguments. |
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1092 When the caller omits an argument the {value} is used. |
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1093 |
| 20856 | 1094 The function will be compiled into instructions when |
| 21499 | 1095 called, or when `:disassemble` or `:defcompile` is |
| 1096 used. Syntax and type errors will be produced at that | |
| 1097 time. | |
| 20856 | 1098 |
| 21499 | 1099 It is possible to nest `:def` inside another `:def` or |
| 1100 `:function` up to about 50 levels deep. | |
| 27459 | 1101 *E1117* |
|
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1102 [!] is used as with `:function`. Note that |
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1103 script-local functions cannot be deleted or redefined |
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1104 later in Vim9 script. They can only be removed by |
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1105 reloading the same script. |
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1106 |
| 27321 | 1107 *:enddef* *E1057* |
| 21499 | 1108 :enddef End of a function defined with `:def`. It should be on |
| 1109 a line by its own. | |
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1110 |
| 24387 | 1111 You may also find this wiki useful. It was written by an early adopter of |
|
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1112 Vim9 script: https://github.com/lacygoill/wiki/blob/master/vim/vim9.md |
|
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1113 |
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1114 If the script the function is defined in is Vim9 script, then script-local |
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1115 variables can be accessed without the "s:" prefix. They must be defined |
| 20856 | 1116 before the function is compiled. If the script the function is defined in is |
| 1117 legacy script, then script-local variables must be accessed with the "s:" | |
| 24387 | 1118 prefix if they do not exist at the time of compiling. |
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1119 |
| 20552 | 1120 *:defc* *:defcompile* |
| 1121 :defc[ompile] Compile functions defined in the current script that | |
| 1122 were not compiled yet. | |
| 1123 This will report errors found during the compilation. | |
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1124 |
| 19404 | 1125 *:disa* *:disassemble* |
| 1126 :disa[ssemble] {func} Show the instructions generated for {func}. | |
| 27321 | 1127 This is for debugging and testing. *E1061* |
|
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1128 Note that for command line completion of {func} you |
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1129 can prepend "s:" to find script-local functions. |
| 19404 | 1130 |
| 24911 | 1131 :disa[ssemble] profile {func} |
| 1132 Like `:disassemble` but with the instructions used for | |
| 23737 | 1133 profiling. |
| 1134 | |
| 24911 | 1135 :disa[ssemble] debug {func} |
| 1136 Like `:disassemble` but with the instructions used for | |
| 1137 debugging. | |
| 1138 | |
| 21250 | 1139 Limitations ~ |
| 1140 | |
| 1141 Local variables will not be visible to string evaluation. For example: > | |
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1142 def MapList(): list<string> |
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1143 var list = ['aa', 'bb', 'cc', 'dd'] |
| 21250 | 1144 return range(1, 2)->map('list[v:val]') |
| 1145 enddef | |
| 1146 | |
| 1147 The map argument is a string expression, which is evaluated without the | |
| 1148 function scope. Instead, use a lambda: > | |
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1149 def MapList(): list<string> |
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1150 var list = ['aa', 'bb', 'cc', 'dd'] |
| 25973 | 1151 return range(1, 2)->map((_, v) => list[v]) |
| 21250 | 1152 enddef |
| 1153 | |
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1154 For commands that are not compiled, such as `:edit`, backtick expansion can be |
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1155 used and it can use the local scope. Example: > |
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1156 def Replace() |
|
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1157 var fname = 'blah.txt' |
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1158 edit `=fname` |
| 25402 | 1159 enddef |
| 1160 | |
| 24278 | 1161 Closures defined in a loop will share the same context. For example: > |
| 1162 var flist: list<func> | |
| 25402 | 1163 for i in range(5) |
| 24278 | 1164 var inloop = i |
| 1165 flist[i] = () => inloop | |
| 1166 endfor | |
| 25402 | 1167 echo range(5)->map((i, _) => flist[i]()) |
| 1168 # Result: [4, 4, 4, 4, 4] | |
| 24278 | 1169 |
| 1170 The "inloop" variable will exist only once, all closures put in the list refer | |
| 25402 | 1171 to the same instance, which in the end will have the value 4. This is |
| 1172 efficient, also when looping many times. If you do want a separate context | |
| 1173 for each closure call a function to define it: > | |
| 1174 def GetClosure(i: number): func | |
| 1175 var infunc = i | |
| 1176 return () => infunc | |
| 24278 | 1177 enddef |
| 1178 | |
| 1179 var flist: list<func> | |
| 25402 | 1180 for i in range(5) |
| 1181 flist[i] = GetClosure(i) | |
| 24278 | 1182 endfor |
| 25402 | 1183 echo range(5)->map((i, _) => flist[i]()) |
| 1184 # Result: [0, 1, 2, 3, 4] | |
| 24278 | 1185 |
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1186 ============================================================================== |
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1187 |
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1188 4. Types *vim9-types* |
| 27321 | 1189 *E1008* *E1009* *E1010* *E1012* |
| 1190 *E1013* *E1029* *E1030* | |
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1191 The following builtin types are supported: |
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1192 bool |
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1193 number |
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1194 float |
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1195 string |
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1196 blob |
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1197 list<{type}> |
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1198 dict<{type}> |
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1199 job |
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1200 channel |
| 19646 | 1201 func |
| 19968 | 1202 func: {type} |
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1203 func({type}, ...) |
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1204 func({type}, ...): {type} |
| 27321 | 1205 void |
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1206 |
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1207 Not supported yet: |
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1208 tuple<a: {type}, b: {type}, ...> |
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1209 |
| 25161 | 1210 These types can be used in declarations, but no simple value will actually |
| 27321 | 1211 have the "void" type. Trying to use a void (e.g. a function without a |
| 1212 return value) results in error *E1031* . | |
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1213 |
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1214 There is no array type, use list<{type}> instead. For a list constant an |
|
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1215 efficient implementation is used that avoids allocating lot of small pieces of |
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1216 memory. |
| 27321 | 1217 *E1005* *E1007* |
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1218 A partial and function can be declared in more or less specific ways: |
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1219 func any kind of function reference, no type |
| 19968 | 1220 checking for arguments or return value |
| 25161 | 1221 func: void any number and type of arguments, no return |
| 1222 value | |
|
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1223 func: {type} any number and type of arguments with specific |
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1224 return type |
| 25161 | 1225 |
| 1226 func() function with no argument, does not return a | |
| 1227 value | |
| 1228 func(): void same | |
| 1229 func(): {type} function with no argument and return type | |
| 1230 | |
| 19968 | 1231 func({type}) function with argument type, does not return |
|
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1232 a value |
| 19968 | 1233 func({type}): {type} function with argument type and return type |
| 1234 func(?{type}) function with type of optional argument, does | |
| 1235 not return a value | |
| 1236 func(...{type}) function with type of variable number of | |
| 1237 arguments, does not return a value | |
| 1238 func({type}, ?{type}, ...{type}): {type} | |
| 1239 function with: | |
| 1240 - type of mandatory argument | |
| 1241 - type of optional argument | |
| 1242 - type of variable number of arguments | |
| 1243 - return type | |
|
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1244 |
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1245 If the return type is "void" the function does not return a value. |
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1246 |
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1247 The reference can also be a |Partial|, in which case it stores extra arguments |
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1248 and/or a dictionary, which are not visible to the caller. Since they are |
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1249 called in the same way the declaration is the same. |
|
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1250 |
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1251 Custom types can be defined with `:type`: > |
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1252 :type MyList list<string> |
|
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1253 Custom types must start with a capital letter, to avoid name clashes with |
|
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1254 builtin types added later, similarly to user functions. |
|
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1255 {not implemented yet} |
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1256 |
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1257 And classes and interfaces can be used as types: > |
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1258 :class MyClass |
|
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1259 :var mine: MyClass |
|
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1260 |
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1261 :interface MyInterface |
|
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1262 :var mine: MyInterface |
|
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1263 |
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1264 :class MyTemplate<Targ> |
|
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1265 :var mine: MyTemplate<number> |
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1266 :var mine: MyTemplate<string> |
|
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1267 |
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1268 :class MyInterface<Targ> |
|
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1269 :var mine: MyInterface<number> |
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1270 :var mine: MyInterface<string> |
|
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1271 {not implemented yet} |
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1272 |
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1273 |
|
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1274 Variable types and type casting ~ |
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1275 *variable-types* |
|
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1276 Variables declared in Vim9 script or in a `:def` function have a type, either |
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1277 specified explicitly or inferred from the initialization. |
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1278 |
|
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1279 Global, buffer, window and tab page variables do not have a specific type, the |
|
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1280 value can be changed at any time, possibly changing the type. Therefore, in |
|
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1281 compiled code the "any" type is assumed. |
|
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1282 |
|
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1283 This can be a problem when the "any" type is undesired and the actual type is |
|
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1284 expected to always be the same. For example, when declaring a list: > |
|
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1285 var l: list<number> = [1, g:two] |
| 23305 | 1286 At compile time Vim doesn't know the type of "g:two" and the expression type |
| 1287 becomes list<any>. An instruction is generated to check the list type before | |
| 1288 doing the assignment, which is a bit inefficient. | |
| 27459 | 1289 *type-casting* *E1104* |
| 23305 | 1290 To avoid this, use a type cast: > |
|
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1291 var l: list<number> = [1, <number>g:two] |
| 23305 | 1292 The compiled code will then only check that "g:two" is a number and give an |
| 1293 error if it isn't. This is called type casting. | |
|
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1294 |
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1295 The syntax of a type cast is: "<" {type} ">". There cannot be white space |
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1296 after the "<" or before the ">" (to avoid them being confused with |
|
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1297 smaller-than and bigger-than operators). |
|
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1298 |
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1299 The semantics is that, if needed, a runtime type check is performed. The |
|
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1300 value is not actually changed. If you need to change the type, e.g. to change |
|
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1301 it to a string, use the |string()| function. Or use |str2nr()| to convert a |
|
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1302 string to a number. |
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1303 |
|
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1304 |
|
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1305 Type inference ~ |
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1306 *type-inference* |
|
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1307 In general: Whenever the type is clear it can be omitted. For example, when |
|
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1308 declaring a variable and giving it a value: > |
|
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1309 var name = 0 # infers number type |
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1310 var name = 'hello' # infers string type |
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1311 |
|
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1312 The type of a list and dictionary comes from the common type of the values. |
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1313 If the values all have the same type, that type is used for the list or |
|
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1314 dictionary. If there is a mix of types, the "any" type is used. > |
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1315 [1, 2, 3] list<number> |
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1316 ['a', 'b', 'c'] list<string> |
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1317 [1, 'x', 3] list<any> |
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1318 |
| 25161 | 1319 The common type of function references, if they do not all have the same |
| 1320 number of arguments, uses "(...)" to indicate the number of arguments is not | |
| 1321 specified. For example: > | |
| 1322 def Foo(x: bool) | |
| 1323 enddef | |
| 1324 def Bar(x: bool, y: bool) | |
| 1325 enddef | |
| 1326 var funclist = [Foo, Bar] | |
| 1327 echo funclist->typename() | |
| 1328 Results in: | |
| 1329 list<func(...)> | |
| 1330 | |
| 24387 | 1331 For script-local variables in Vim9 script the type is checked, also when the |
| 1332 variable was declared in a legacy function. | |
| 1333 | |
| 27459 | 1334 When a type has been declared this is attached to a list or string. When |
| 1335 later some expression attempts to change the type an error will be given: > | |
| 1336 var ll: list<number> = [1, 2, 3] | |
| 1337 ll->extend('x') # Error, 'x' is not a number | |
| 1338 | |
| 1339 If the type is inferred then the type is allowed to change: > | |
| 1340 [1, 2, 3]->extend('x') # result: [1, 2, 3, 'x'] | |
| 1341 | |
| 21991 | 1342 |
|
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1343 Stricter type checking ~ |
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1344 *type-checking* |
| 21991 | 1345 In legacy Vim script, where a number was expected, a string would be |
| 1346 automatically converted to a number. This was convenient for an actual number | |
| 24387 | 1347 such as "123", but leads to unexpected problems (and no error message) if the |
| 21991 | 1348 string doesn't start with a number. Quite often this leads to hard-to-find |
| 1349 bugs. | |
| 1350 | |
| 1351 In Vim9 script this has been made stricter. In most places it works just as | |
| 22171 | 1352 before, if the value used matches the expected type. There will sometimes be |
| 1353 an error, thus breaking backwards compatibility. For example: | |
| 21991 | 1354 - Using a number other than 0 or 1 where a boolean is expected. *E1023* |
| 25161 | 1355 - Using a string value when setting a number option. |
| 27459 | 1356 - Using a number where a string is expected. *E1024* *E1105* |
| 21991 | 1357 |
| 25973 | 1358 One consequence is that the item type of a list or dict given to |map()| must |
| 24024 | 1359 not change. This will give an error in Vim9 script: > |
| 25973 | 1360 echo map([1, 2, 3], (i, v) => 'item ' .. i) |
| 24024 | 1361 E1012: Type mismatch; expected number but got string |
| 25973 | 1362 Instead use |mapnew()|: > |
| 1363 echo mapnew([1, 2, 3], (i, v) => 'item ' .. i) | |
| 25161 | 1364 ['item 0', 'item 1', 'item 2'] |
| 1365 | |
| 1366 If the item type was determined to be "any" it can change to a more specific | |
| 25973 | 1367 type. E.g. when a list of mixed types gets changed to a list of strings: > |
| 25161 | 1368 var mylist = [1, 2.0, '3'] |
| 1369 # typename(mylist) == "list<any>" | |
| 1370 map(mylist, (i, v) => 'item ' .. i) | |
| 1371 # typename(mylist) == "list<string>", no error | |
| 1372 | |
| 24024 | 1373 Same for |extend()|, use |extendnew()| instead, and for |flatten()|, use |
| 1374 |flattennew()| instead. | |
| 23573 | 1375 |
|
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1376 ============================================================================== |
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1377 |
|
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1378 5. Namespace, Import and Export |
|
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1379 *vim9script* *vim9-export* *vim9-import* |
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1380 |
| 27162 | 1381 A Vim9 script can be written to be imported. This means that some items are |
| 1382 intentionally exported, made available to other scripts. When the exporting | |
| 1383 script is imported in another script, these exported items can then be used in | |
| 1384 that script. All the other items remain script-local in the exporting script | |
| 1385 and cannot be accessed by the importing script. | |
| 27036 | 1386 |
| 1387 This mechanism exists for writing a script that can be sourced (imported) by | |
| 1388 other scripts, while making sure these other scripts only have access to what | |
| 1389 you want them to. This also avoids using the global namespace, which has a | |
| 1390 risc of name collisions. For example when you have two plugins with similar | |
| 1391 functionality. | |
|
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1392 |
| 27162 | 1393 You can cheat by using the global namespace explicitly. That should be done |
| 1394 only for things that really are global. | |
| 21991 | 1395 |
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1396 |
|
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1397 Namespace ~ |
|
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|
1398 *vim9-namespace* |
| 19303 | 1399 To recognize a file that can be imported the `vim9script` statement must |
|
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|
1400 appear as the first statement in the file (see |vim9-mix| for an exception). |
|
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|
1401 It tells Vim to interpret the script in its own namespace, instead of the |
|
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|
1402 global namespace. If a file starts with: > |
|
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1403 vim9script |
|
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|
1404 var myvar = 'yes' |
|
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1405 Then "myvar" will only exist in this file. While without `vim9script` it would |
|
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|
1406 be available as `g:myvar` from any other script and function. |
| 27459 | 1407 *E1101* |
|
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|
1408 The variables at the file level are very much like the script-local "s:" |
| 20115 | 1409 variables in legacy Vim script, but the "s:" is omitted. And they cannot be |
| 1410 deleted. | |
|
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1411 |
| 20115 | 1412 In Vim9 script the global "g:" namespace can still be used as before. And the |
| 1413 "w:", "b:" and "t:" namespaces. These have in common that variables are not | |
| 1414 declared and they can be deleted. | |
|
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|
1415 |
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1416 A side effect of `:vim9script` is that the 'cpoptions' option is set to the |
|
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|
1417 Vim default value, like with: > |
|
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|
1418 :set cpo&vim |
|
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|
1419 One of the effects is that |line-continuation| is always enabled. |
|
24150
4919f2d8d7fd
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|
1420 The original value of 'cpoptions' is restored at the end of the script, while |
|
4919f2d8d7fd
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|
1421 flags added or removed in the script are also added to or removed from the |
|
4919f2d8d7fd
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|
1422 original value to get the same effect. The order of flags may change. |
|
26745
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patch 8.2.3901: Vim9: Cannot set 'cpo' in main .vimrc if using Vim9 script
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26708
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|
1423 In the |vimrc| file sourced on startup this does not happen. |
|
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|
1424 |
|
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|
1425 *vim9-mix* |
|
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|
1426 There is one way to use both legacy and Vim9 syntax in one script file: > |
|
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|
1427 " comments may go here |
|
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|
1428 if !has('vim9script') |
|
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|
1429 " legacy script commands go here |
|
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|
1430 finish |
|
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|
1431 endif |
|
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|
1432 vim9script |
|
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|
1433 # Vim9 script commands go here |
|
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|
1434 This allows for writing a script that takes advantage of the Vim9 script |
| 24024 | 1435 syntax if possible, but will also work on a Vim version without it. |
|
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|
1436 |
|
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|
1437 This can only work in two ways: |
|
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|
1438 1. The "if" statement evaluates to false, the commands up to `endif` are |
|
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|
1439 skipped and `vim9script` is then the first command actually executed. |
|
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|
1440 2. The "if" statement evaluates to true, the commands up to `endif` are |
|
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|
1441 executed and `finish` bails out before reaching `vim9script`. |
|
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|
1442 |
|
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|
1443 |
|
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|
1444 Export ~ |
|
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|
1445 *:export* *:exp* |
| 21499 | 1446 Exporting an item can be written as: > |
|
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|
1447 export const EXPORTED_CONST = 1234 |
|
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|
1448 export var someValue = ... |
|
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|
1449 export final someValue = ... |
|
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|
1450 export const someValue = ... |
|
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|
1451 export def MyFunc() ... |
|
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|
1452 export class MyClass ... |
|
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|
1453 export interface MyClass ... |
| 27321 | 1454 < *E1043* *E1044* |
|
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|
1455 As this suggests, only constants, variables, `:def` functions and classes can |
|
24888
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|
1456 be exported. {not implemented yet: class, interface} |
|
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|
1457 |
| 20856 | 1458 *E1042* |
| 1459 `:export` can only be used in Vim9 script, at the script level. | |
|
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|
1460 |
|
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|
1461 |
|
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|
1462 Import ~ |
| 27321 | 1463 *:import* *:imp* *E1094* *E1047* |
| 1464 *E1048* *E1049* *E1053* *E1071* | |
|
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|
1465 The exported items can be imported in another Vim9 script: > |
|
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|
1466 import "myscript.vim" |
|
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|
1467 |
|
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|
1468 This makes each item available as "myscript.item". |
| 27321 | 1469 *:import-as* |
|
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|
1470 In case the name is long or ambiguous, another name can be specified: > |
| 27036 | 1471 import "thatscript.vim" as that |
| 27321 | 1472 < *E1060* |
| 27036 | 1473 Then you can use "that.EXPORTED_CONST", "that.someValue", etc. You are free |
| 1474 to choose the name "that". Use something that will be recognized as referring | |
| 27459 | 1475 to the imported script. Avoid command names, command modifiers and builtin |
| 1476 function names, because the name will shadow them. | |
| 1477 If the name starts with a capital letter it can also shadow global user | |
| 1478 commands and functions. Also, you cannot use the name for something else in | |
| 1479 the script, such as a function or variable name. | |
|
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|
1480 |
| 27036 | 1481 In case the dot in the name is undesired, a local reference can be made for a |
| 1482 function: > | |
| 1483 var LongFunc = that.LongFuncName | |
|
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|
1484 |
|
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|
1485 This also works for constants: > |
| 27036 | 1486 const MAXLEN = that.MAX_LEN_OF_NAME |
|
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|
1487 |
| 27036 | 1488 This does not work for variables, since the value would be copied once and |
| 1489 when changing the variable the copy will change, not the original variable. | |
| 1490 You will need to use the full name, with the dot. | |
|
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|
1491 |
| 27321 | 1492 The full syntax of the command is: |
| 1493 import {filename} [as {name}] | |
| 1494 Where {filename} is an expression that must evaluate to a string. Without the | |
| 1495 "as {name}" part it must end in ".vim". {name} must consist of letters, | |
| 1496 digits and '_', like |internal-variables|. | |
| 1497 | |
| 22171 | 1498 `:import` can also be used in legacy Vim script. The imported items still |
| 1499 become script-local, even when the "s:" prefix is not given. | |
| 1500 | |
|
25282
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|
1501 `:import` can not be used in a function. Imported items are intended to exist |
|
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|
1502 at the script level and only imported once. |
|
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|
1503 |
|
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|
1504 The script name after `import` can be: |
|
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1505 - A relative path, starting "." or "..". This finds a file relative to the |
|
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|
1506 location of the script file itself. This is useful to split up a large |
|
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|
1507 plugin into several files. |
|
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|
1508 - An absolute path, starting with "/" on Unix or "D:/" on MS-Windows. This |
| 22723 | 1509 will rarely be used. |
|
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1510 - A path not being relative or absolute. This will be found in the |
|
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|
1511 "import" subdirectories of 'runtimepath' entries. The name will usually be |
|
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|
1512 longer and unique, to avoid loading the wrong file. |
| 25619 | 1513 Note that "after/import" is not used. |
|
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1514 |
| 27036 | 1515 If the name does not end in ".vim" then the use of "as name" is required. |
| 1516 | |
|
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|
1517 Once a vim9 script file has been imported, the result is cached and used the |
|
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|
1518 next time the same script is imported. It will not be read again. |
|
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1519 |
|
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|
1520 It is not allowed to import the same script twice, also when using two |
|
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|
1521 different "as" names. |
| 27036 | 1522 |
| 1523 When using the imported name the dot and the item name must be in the same | |
| 1524 line, there can be no line break: > | |
| 1525 echo that. | |
| 1526 name # Error! | |
| 1527 echo that | |
| 1528 .name # Error! | |
| 1529 < *:import-cycle* | |
|
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|
1530 The `import` commands are executed when encountered. If that script (directly |
|
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1531 or indirectly) imports the current script, then items defined after the |
|
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|
1532 `import` won't be processed yet. Therefore cyclic imports can exist, but may |
|
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1533 result in undefined items. |
|
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1534 |
|
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1535 |
| 27162 | 1536 Importing an autoload script ~ |
|
27043
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patch 8.2.4050: Vim9: need to prefix every item in an autoload script
Bram Moolenaar <Bram@vim.org>
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|
1537 *vim9-autoload* |
|
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1538 For optimal startup speed, loading scripts should be postponed until they are |
|
27043
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|
1539 actually needed. Using the autoload mechanism is recommended: |
|
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1540 |
|
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1541 1. In the plugin define user commands, functions and/or mappings that refer to |
|
27043
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1542 items imported from an autoload script. > |
|
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|
1543 import autoload 'for/search.vim' |
|
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1544 command -nargs=1 SearchForStuff search.Stuff(<f-args>) |
|
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1545 |
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|
1546 < This goes in .../plugin/anyname.vim. "anyname.vim" can be freely chosen. |
|
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|
1547 The "SearchForStuff" command is now available to the user. |
|
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1548 |
|
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|
1549 The "autoload" argument to `:import` means that the script is not loaded |
|
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|
1550 until one of the items is actually used. The script will be found under |
|
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|
1551 the "autoload" directory in 'runtimepath' instead of the "import" |
|
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1552 directory. |
|
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1553 |
|
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1554 2. In the autoload script put the bulk of the code. > |
|
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|
1555 vim9script |
|
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|
1556 export def Stuff(arg: string) |
|
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1557 ... |
|
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1558 |
|
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|
1559 < This goes in .../autoload/for/search.vim. |
|
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1560 |
|
27215
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|
1561 Putting the "search.vim" script under the "/autoload/for/" directory has |
|
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|
1562 the effect that "for#search#" will be prefixed to every exported item. The |
|
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|
1563 prefix is obtained from the file name, as you would to manually in a |
|
5b54f413d132
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|
1564 legacy autoload script. Thus the exported function can be found with |
|
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|
1565 "for#search#Stuff", but you would normally use `import autoload` and not |
|
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|
1566 use the prefix. |
|
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1567 |
|
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1568 You can split up the functionality and import other scripts from the |
|
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|
1569 autoload script as you like. This way you can share code between plugins. |
|
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1570 |
| 27162 | 1571 For defining a mapping that uses the imported autoload script the special key |
| 1572 |<ScriptCmd>| is useful. It allows for a command in a mapping to use the | |
| 1573 script context of where the mapping was defined. | |
| 1574 | |
|
21771
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|
1575 When compiling a `:def` function and a function in an autoload script is |
|
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|
1576 encountered, the script is not loaded until the `:def` function is called. |
|
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1577 This also means you get any errors only at runtime, since the argument and |
|
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|
1578 return types are not known yet. |
|
21771
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1579 |
| 27162 | 1580 For testing the |test_override()| function can be used to have the |
| 1581 `import autoload` load the script right away, so that the items and types can | |
| 1582 be checked without waiting for them to be actually used: > | |
| 1583 test_override('autoload', 1) | |
| 1584 Reset it later with: > | |
| 1585 test_override('autoload', 0) | |
| 1586 Or: > | |
| 1587 test_override('ALL', 0) | |
| 1588 | |
|
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1589 |
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1590 Import in legacy Vim script ~ |
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1591 |
| 20856 | 1592 If an `import` statement is used in legacy Vim script, the script-local "s:" |
| 27162 | 1593 namespace will be used for the imported items, even when "s:" is not |
| 1594 specified. | |
|
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1595 |
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|
1596 |
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|
1597 ============================================================================== |
|
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1598 |
| 22328 | 1599 6. Future work: classes *vim9-classes* |
| 1600 | |
| 1601 Above "class" was mentioned a few times, but it has not been implemented yet. | |
|
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1602 Most of Vim9 script can be created without this functionality, and since |
| 22328 | 1603 implementing classes is going to be a lot of work, it is left for the future. |
| 1604 For now we'll just make sure classes can be added later. | |
| 1605 | |
| 1606 Thoughts: | |
|
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1607 - `class` / `endclass`, the whole class must be in one file |
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1608 - Class names are always CamelCase (to avoid a name clash with builtin types) |
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1609 - A single constructor called "constructor" |
| 22328 | 1610 - Single inheritance with `class ThisClass extends BaseClass` |
|
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1611 - `abstract class` (class with incomplete implementation) |
|
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1612 - `interface` / `endinterface` (abstract class without any implementation) |
| 22328 | 1613 - `class SomeClass implements SomeInterface` |
| 1614 - Generics for class: `class <Tkey, Tentry>` | |
| 1615 - Generics for function: `def <Tkey> GetLast(key: Tkey)` | |
| 1616 | |
|
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|
1617 Again, much of this is from TypeScript with a slightly different syntax. |
| 22328 | 1618 |
| 1619 Some things that look like good additions: | |
| 1620 - Use a class as an interface (like Dart) | |
| 1621 - Extend a class with methods, using an import (like Dart) | |
|
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|
1622 - Mixins |
|
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1623 - For testing: Mock mechanism |
| 22328 | 1624 |
| 1625 An important class that will be provided is "Promise". Since Vim is single | |
| 1626 threaded, connecting asynchronous operations is a natural way of allowing | |
| 1627 plugins to do their work without blocking the user. It's a uniform way to | |
| 1628 invoke callbacks and handle timeouts and errors. | |
| 1629 | |
|
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|
1630 Some examples: > |
|
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1631 |
|
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|
1632 abstract class Person |
|
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|
1633 static const prefix = 'xxx' |
|
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1634 var name: string |
|
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1635 |
|
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|
1636 def constructor(name: string) |
| 25402 | 1637 this.name = name |
|
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1638 enddef |
|
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1639 |
|
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|
1640 def display(): void |
|
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|
1641 echo name |
|
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1642 enddef |
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1643 |
|
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|
1644 abstract def find(string): Person |
|
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1645 endclass |
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1646 |
| 22328 | 1647 ============================================================================== |
| 1648 | |
|
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1649 9. Rationale *vim9-rationale* |
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1650 |
|
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|
1651 The :def command ~ |
|
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1652 |
|
22391
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|
1653 Plugin writers have asked for much faster Vim script. Investigations have |
| 19303 | 1654 shown that keeping the existing semantics of function calls make this close to |
|
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1655 impossible, because of the overhead involved with calling a function, setting |
|
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|
1656 up the local function scope and executing lines. There are many details that |
|
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1657 need to be handled, such as error messages and exceptions. The need to create |
|
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1658 a dictionary for a: and l: scopes, the a:000 list and several others add too |
|
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|
1659 much overhead that cannot be avoided. |
|
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1660 |
|
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|
1661 Therefore the `:def` method to define a new-style function had to be added, |
|
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|
1662 which allows for a function with different semantics. Most things still work |
|
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1663 as before, but some parts do not. A new way to define a function was |
|
22391
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|
1664 considered the best way to separate the legacy style code from Vim9 style code. |
|
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1665 |
|
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|
1666 Using "def" to define a function comes from Python. Other languages use |
|
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1667 "function" which clashes with legacy Vim script. |
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1668 |
|
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1669 |
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1670 Type checking ~ |
|
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1671 |
|
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1672 When compiling lines of Vim commands into instructions as much as possible |
|
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1673 should be done at compile time. Postponing it to runtime makes the execution |
|
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1674 slower and means mistakes are found only later. For example, when |
|
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|
1675 encountering the "+" character and compiling this into a generic add |
| 23666 | 1676 instruction, at runtime the instruction would have to inspect the type of the |
| 1677 arguments and decide what kind of addition to do. And when the type is | |
| 1678 dictionary throw an error. If the types are known to be numbers then an "add | |
| 1679 number" instruction can be used, which is faster. The error can be given at | |
| 1680 compile time, no error handling is needed at runtime, since adding two numbers | |
| 1681 cannot fail. | |
|
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1682 |
|
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1683 The syntax for types, using <type> for compound types, is similar to Java. It |
|
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|
1684 is easy to understand and widely used. The type names are what were used in |
|
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|
1685 Vim before, with some additions such as "void" and "bool". |
|
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1686 |
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|
1687 |
| 22328 | 1688 Removing clutter and weirdness ~ |
| 20856 | 1689 |
| 22328 | 1690 Once decided that `:def` functions have different syntax than legacy functions, |
| 1691 we are free to add improvements to make the code more familiar for users who | |
| 1692 know popular programming languages. In other words: remove weird things that | |
|
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|
1693 only Vim does. |
| 22328 | 1694 |
| 1695 We can also remove clutter, mainly things that were done to make Vim script | |
|
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|
1696 backwards compatible with the good old Vi commands. |
| 20856 | 1697 |
| 22328 | 1698 Examples: |
| 1699 - Drop `:call` for calling a function and `:eval` for manipulating data. | |
| 1700 - Drop using a leading backslash for line continuation, automatically figure | |
| 1701 out where an expression ends. | |
| 20856 | 1702 |
| 22328 | 1703 However, this does require that some things need to change: |
| 1704 - Comments start with # instead of ", to avoid confusing them with strings. | |
|
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1705 This is good anyway, it is known from several popular languages. |
| 22328 | 1706 - Ex command ranges need to be prefixed with a colon, to avoid confusion with |
| 1707 expressions (single quote can be a string or a mark, "/" can be divide or a | |
| 1708 search command, etc.). | |
| 1709 | |
| 1710 Goal is to limit the differences. A good criteria is that when the old syntax | |
|
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|
1711 is accidentally used you are very likely to get an error message. |
| 20856 | 1712 |
| 1713 | |
|
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|
1714 Syntax and semantics from popular languages ~ |
|
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1715 |
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1716 Script writers have complained that the Vim script syntax is unexpectedly |
|
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1717 different from what they are used to. To reduce this complaint popular |
| 20856 | 1718 languages are used as an example. At the same time, we do not want to abandon |
| 1719 the well-known parts of legacy Vim script. | |
|
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1720 |
|
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1721 For many things TypeScript is followed. It's a recent language that is |
|
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1722 gaining popularity and has similarities with Vim script. It also has a |
| 22328 | 1723 mix of static typing (a variable always has a known value type) and dynamic |
|
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|
1724 typing (a variable can have different types, this changes at runtime). Since |
| 22328 | 1725 legacy Vim script is dynamically typed and a lot of existing functionality |
| 1726 (esp. builtin functions) depends on that, while static typing allows for much | |
| 1727 faster execution, we need to have this mix in Vim9 script. | |
| 1728 | |
| 22171 | 1729 There is no intention to completely match TypeScript syntax and semantics. We |
| 1730 just want to take those parts that we can use for Vim and we expect Vim users | |
| 22328 | 1731 will be happy with. TypeScript is a complex language with its own history, |
| 1732 advantages and disadvantages. To get an idea of the disadvantages read the | |
| 1733 book: "JavaScript: The Good Parts". Or find the article "TypeScript: the good | |
|
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1734 parts" and read the "Things to avoid" section. |
|
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1735 |
| 22328 | 1736 People familiar with other languages (Java, Python, etc.) will also find |
| 1737 things in TypeScript that they do not like or do not understand. We'll try to | |
| 1738 avoid those things. | |
|
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1739 |
|
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|
1740 Specific items from TypeScript we avoid: |
|
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|
1741 - Overloading "+", using it both for addition and string concatenation. This |
|
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|
1742 goes against legacy Vim script and often leads to mistakes. For that reason |
|
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|
1743 we will keep using ".." for string concatenation. Lua also uses ".." this |
|
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|
1744 way. And it allows for conversion to string for more values. |
|
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1745 - TypeScript can use an expression like "99 || 'yes'" in a condition, but |
|
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|
1746 cannot assign the value to a boolean. That is inconsistent and can be |
|
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|
1747 annoying. Vim recognizes an expression with && or || and allows using the |
|
26755
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|
1748 result as a bool. The |falsy-operator| was added for the mechanism to use a |
|
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|
1749 default value. |
|
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1750 - TypeScript considers an empty string as Falsy, but an empty list or dict as |
|
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|
1751 Truthy. That is inconsistent. In Vim an empty list and dict are also |
|
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|
1752 Falsy. |
|
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|
1753 - TypeScript has various "Readonly" types, which have limited usefulness, |
|
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|
1754 since a type cast can remove the immutable nature. Vim locks the value, |
|
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1755 which is more flexible, but is only checked at runtime. |
| 27459 | 1756 - TypeScript has a complicated "import" statement that does not match how the |
| 1757 Vim import mechanism works. A much simpler mechanism is used instead, which | |
| 1758 matches that the imported script is only sourced once. | |
| 22171 | 1759 |
|
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1760 |
|
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|
1761 Declarations ~ |
|
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1762 |
|
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|
1763 Legacy Vim script uses `:let` for every assignment, while in Vim9 declarations |
|
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|
1764 are used. That is different, thus it's good to use a different command: |
|
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|
1765 `:var`. This is used in many languages. The semantics might be slightly |
|
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|
1766 different, but it's easily recognized as a declaration. |
|
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1767 |
| 23047 | 1768 Using `:const` for constants is common, but the semantics varies. Some |
|
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|
1769 languages only make the variable immutable, others also make the value |
|
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|
1770 immutable. Since "final" is well known from Java for only making the variable |
|
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|
1771 immutable we decided to use that. And then `:const` can be used for making |
|
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|
1772 both immutable. This was also used in legacy Vim script and the meaning is |
|
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|
1773 almost the same. |
|
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|
1774 |
|
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|
1775 What we end up with is very similar to Dart: > |
|
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|
1776 :var name # mutable variable and value |
|
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1777 :final name # immutable variable, mutable value |
|
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1778 :const name # immutable variable and value |
|
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1779 |
|
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|
1780 Since legacy and Vim9 script will be mixed and global variables will be |
|
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|
1781 shared, optional type checking is desirable. Also, type inference will avoid |
|
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|
1782 the need for specifying the type in many cases. The TypeScript syntax fits |
|
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|
1783 best for adding types to declarations: > |
|
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|
1784 var name: string # string type is specified |
|
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|
1785 ... |
|
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1786 name = 'John' |
|
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1787 const greeting = 'hello' # string type is inferred |
|
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1788 |
|
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|
1789 This is how we put types in a declaration: > |
|
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1790 var mylist: list<string> |
|
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|
1791 final mylist: list<string> = ['foo'] |
|
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|
1792 def Func(arg1: number, arg2: string): bool |
|
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1793 |
|
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|
1794 Two alternatives were considered: |
|
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1795 1. Put the type before the name, like Dart: > |
|
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1796 var list<string> mylist |
|
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1797 final list<string> mylist = ['foo'] |
|
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1798 def Func(number arg1, string arg2) bool |
|
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1799 2. Put the type after the variable name, but do not use a colon, like Go: > |
|
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1800 var mylist list<string> |
|
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1801 final mylist list<string> = ['foo'] |
|
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1802 def Func(arg1 number, arg2 string) bool |
|
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1803 |
|
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|
1804 The first is more familiar for anyone used to C or Java. The second one |
| 22565 | 1805 doesn't really have an advantage over the first, so let's discard the second. |
|
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1806 |
|
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1807 Since we use type inference the type can be left out when it can be inferred |
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1808 from the value. This means that after `var` we don't know if a type or a name |
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1809 follows. That makes parsing harder, not only for Vim but also for humans. |
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1810 Also, it will not be allowed to use a variable name that could be a type name, |
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1811 using `var string string` is too confusing. |
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1812 |
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1813 The chosen syntax, using a colon to separate the name from the type, adds |
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1814 punctuation, but it actually makes it easier to recognize the parts of a |
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1815 declaration. |
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1816 |
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1817 |
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1818 Expressions ~ |
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1819 |
| 22565 | 1820 Expression evaluation was already close to what other languages are doing. |
| 1821 Some details are unexpected and can be improved. For example a boolean | |
| 1822 condition would accept a string, convert it to a number and check if the | |
| 1823 number is non-zero. This is unexpected and often leads to mistakes, since | |
| 1824 text not starting with a number would be converted to zero, which is | |
| 22723 | 1825 considered false. Thus using a string for a condition would often not give an |
| 1826 error and be considered false. That is confusing. | |
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1827 |
| 23047 | 1828 In Vim9 type checking is stricter to avoid mistakes. Where a condition is |
| 22565 | 1829 used, e.g. with the `:if` command and the `||` operator, only boolean-like |
| 1830 values are accepted: | |
| 1831 true: `true`, `v:true`, `1`, `0 < 9` | |
| 1832 false: `false`, `v:false`, `0`, `0 > 9` | |
| 1833 Note that the number zero is false and the number one is true. This is more | |
| 22723 | 1834 permissive than most other languages. It was done because many builtin |
| 22565 | 1835 functions return these values. |
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1836 |
| 22565 | 1837 If you have any type of value and want to use it as a boolean, use the `!!` |
| 1838 operator: | |
| 24751 | 1839 true: `!!'text'`, `!![99]`, `!!{'x': 1}`, `!!99` |
| 22565 | 1840 false: `!!''`, `!![]`, `!!{}` |
| 1841 | |
| 1842 From a language like JavaScript we have this handy construct: > | |
| 1843 GetName() || 'unknown' | |
| 1844 However, this conflicts with only allowing a boolean for a condition. | |
| 1845 Therefore the "??" operator was added: > | |
| 1846 GetName() ?? 'unknown' | |
| 1847 Here you can explicitly express your intention to use the value as-is and not | |
| 1848 result in a boolean. This is called the |falsy-operator|. | |
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1849 |
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1850 |
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1851 Import and Export ~ |
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1852 |
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1853 A problem of legacy Vim script is that by default all functions and variables |
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1854 are global. It is possible to make them script-local, but then they are not |
| 22171 | 1855 available in other scripts. This defies the concept of a package that only |
| 1856 exports selected items and keeps the rest local. | |
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1857 |
| 21825 | 1858 In Vim9 script a mechanism very similar to the JavaScript import and export |
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1859 mechanism is supported. It is a variant to the existing `:source` command |
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1860 that works like one would expect: |
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1861 - Instead of making everything global by default, everything is script-local, |
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1862 unless exported. |
| 22171 | 1863 - When importing a script the symbols that are imported are explicitly listed, |
| 1864 avoiding name conflicts and failures if functionality is added later. | |
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1865 - The mechanism allows for writing a big, long script with a very clear API: |
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1866 the exported function(s) and class(es). |
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1867 - By using relative paths loading can be much faster for an import inside of a |
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1868 package, no need to search many directories. |
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1869 - Once an import has been used, it can be cached and loading it again can be |
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1870 avoided. |
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1871 - The Vim-specific use of "s:" to make things script-local can be dropped. |
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1872 |
| 20856 | 1873 When sourcing a Vim9 script from a legacy script, only the items defined |
| 1874 globally can be used, not the exported items. Alternatives considered: | |
| 1875 - All the exported items become available as script-local items. This makes | |
| 22171 | 1876 it uncontrollable what items get defined and likely soon leads to trouble. |
| 20856 | 1877 - Use the exported items and make them global. Disadvantage is that it's then |
| 1878 not possible to avoid name clashes in the global namespace. | |
| 1879 - Completely disallow sourcing a Vim9 script, require using `:import`. That | |
| 1880 makes it difficult to use scripts for testing, or sourcing them from the | |
| 1881 command line to try them out. | |
| 22171 | 1882 Note that you can also use `:import` in legacy Vim script, see above. |
| 20856 | 1883 |
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1884 |
| 22328 | 1885 Compiling functions early ~ |
| 1886 | |
| 1887 Functions are compiled when called or when `:defcompile` is used. Why not | |
| 1888 compile them early, so that syntax and type errors are reported early? | |
| 1889 | |
| 1890 The functions can't be compiled right away when encountered, because there may | |
| 1891 be forward references to functions defined later. Consider defining functions | |
| 1892 A, B and C, where A calls B, B calls C, and C calls A again. It's impossible | |
| 1893 to reorder the functions to avoid forward references. | |
| 1894 | |
| 1895 An alternative would be to first scan through the file to locate items and | |
| 1896 figure out their type, so that forward references are found, and only then | |
| 1897 execute the script and compile the functions. This means the script has to be | |
| 1898 parsed twice, which is slower, and some conditions at the script level, such | |
| 1899 as checking if a feature is supported, are hard to use. An attempt was made | |
| 1900 to see if it works, but it turned out to be impossible to make work nicely. | |
| 1901 | |
| 1902 It would be possible to compile all the functions at the end of the script. | |
| 1903 The drawback is that if a function never gets called, the overhead of | |
| 1904 compiling it counts anyway. Since startup speed is very important, in most | |
| 1905 cases it's better to do it later and accept that syntax and type errors are | |
| 1906 only reported then. In case these errors should be found early, e.g. when | |
| 1907 testing, the `:defcompile` command will help out. | |
| 1908 | |
| 1909 | |
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1910 Why not use an embedded language? ~ |
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1911 |
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1912 Vim supports interfaces to Perl, Python, Lua, Tcl and a few others. But |
| 22328 | 1913 these interfaces have never become widely used, for various reasons. When |
| 1914 Vim9 was designed a decision was made to make these interfaces lower priority | |
| 1915 and concentrate on Vim script. | |
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1916 |
| 22328 | 1917 Still, plugin writers may find other languages more familiar, want to use |
| 1918 existing libraries or see a performance benefit. We encourage plugin authors | |
| 1919 to write code in any language and run it as an external tool, using jobs and | |
| 1920 channels. We can try to make this easier somehow. | |
| 1921 | |
| 1922 Using an external tool also has disadvantages. An alternative is to convert | |
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1923 the tool into Vim script. For that to be possible without too much |
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1924 translation, and keeping the code fast at the same time, the constructs of the |
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1925 tool need to be supported. Since most languages support classes the lack of |
| 22171 | 1926 support for classes in Vim is then a problem. |
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1927 |
| 22328 | 1928 |
| 1929 Classes ~ | |
| 1930 | |
| 1931 Vim supports a kind-of object oriented programming by adding methods to a | |
| 1932 dictionary. With some care this can be made to work, but it does not look | |
| 1933 like real classes. On top of that, it's quite slow, because of the use of | |
| 1934 dictionaries. | |
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1935 |
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1936 The support of classes in Vim9 script is a "minimal common functionality" of |
| 22171 | 1937 class support in most languages. It works much like Java, which is the most |
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1938 popular programming language. |
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1939 |
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1940 |
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1941 |
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1942 vim:tw=78:ts=8:noet:ft=help:norl: |