Mercurial > vim
annotate runtime/doc/vim9.txt @ 28010:c968191a8557
Update runtime files
Commit: https://github.com/vim/vim/commit/1588bc8ebee22f2855f27273fc2234fff370f86c
Author: Bram Moolenaar <Bram@vim.org>
Date: Tue Mar 8 21:35:07 2022 +0000
Update runtime files
| author | Bram Moolenaar <Bram@vim.org> |
|---|---|
| date | Tue, 08 Mar 2022 22:45:09 +0100 |
| parents | 1012048eed26 |
| children | dce918af0c00 |
| rev | line source |
|---|---|
| 28010 | 1 *vim9.txt* For Vim version 8.2. Last change: 2022 Mar 08 |
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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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8 |
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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 |
| 27537 | 59 :vim9[cmd] {cmd} *:vim9* *:vim9cmd* *E1164* |
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60 Evaluate and execute {cmd} using Vim9 script syntax and |
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61 semantics. Useful when typing a command and in a legacy |
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62 script or function. |
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63 |
| 27537 | 64 :leg[acy] {cmd} *:leg* *:legacy* *E1189* *E1234* |
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65 Evaluate and execute {cmd} using legacy script syntax and |
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66 semantics. Only 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 ~ |
| 27537 | 75 *E1146* |
| 22441 | 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: |
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98 `:Print` |
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99 `:append` |
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100 `:change` |
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101 `:d` directly followed by 'd' or 'p'. |
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102 `:insert` |
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103 `:k` |
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104 `:mode` |
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105 `:open` |
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106 `:s` with only flags |
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107 `:t` |
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108 `:xit` |
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109 - Some commands, especially those used for flow control, cannot be shortened. |
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110 E.g., `:throw` cannot be written as `:th`. *E839* |
| 25973 | 111 - You cannot use curly-braces names. |
| 22441 | 112 - A range before a command must be prefixed with a colon: > |
| 23573 | 113 :%s/this/that |
| 25700 | 114 - Executing a register with "@r" does not work, you can prepend a colon or use |
| 115 `:exe`: > | |
| 116 :exe @a | |
| 23573 | 117 - Unless mentioned specifically, the highest |scriptversion| is used. |
| 27162 | 118 - When defining an expression mapping, the expression will be evaluated in the |
| 119 context of the script where it was defined. | |
| 22441 | 120 |
| 121 | |
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122 Comments starting with # ~ |
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123 |
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124 In legacy Vim script comments start with double quote. In Vim9 script |
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125 comments start with #. > |
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126 # declarations |
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127 var count = 0 # number of occurrences |
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128 |
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129 The reason is that a double quote can also be the start of a string. In many |
| 21825 | 130 places, especially halfway through an expression with a line break, it's hard |
| 131 to tell what the meaning is, since both a string and a comment can be followed | |
| 132 by arbitrary text. To avoid confusion only # comments are recognized. This | |
| 133 is the same as in shell scripts and Python programs. | |
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134 |
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135 In Vi # is a command to list text with numbers. In Vim9 script you can use |
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136 `:number` for that. > |
| 27036 | 137 :101 number |
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138 |
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139 To improve readability there must be a space between a command and the # |
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140 that starts a comment: > |
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141 var name = value # comment |
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142 var name = value# error! |
| 27537 | 143 < *E1170* |
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144 Do not start a comment with #{, it looks like the legacy dictionary literal |
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145 and produces an error where this might be confusing. #{{ or #{{{ are OK, |
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146 these can be used to start a fold. |
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147 |
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148 In legacy Vim script # is also used for the alternate file name. In Vim9 |
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149 script you need to use %% instead. Instead of ## use %%% (stands for all |
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150 arguments). |
| 20115 | 151 |
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152 |
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153 Vim9 functions ~ |
| 27459 | 154 *E1099* |
| 20241 | 155 A function defined with `:def` is compiled. Execution is many times faster, |
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156 often 10 to 100 times. |
| 20241 | 157 |
| 20552 | 158 Many errors are already found when compiling, before the function is executed. |
| 20241 | 159 The syntax is strict, to enforce code that is easy to read and understand. |
| 160 | |
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161 Compilation is done when any of these is encountered: |
| 23164 | 162 - the first time the function is called |
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163 - when the `:defcompile` command is encountered in the script after the |
| 21991 | 164 function was defined |
| 165 - `:disassemble` is used for the function. | |
| 166 - a function that is compiled calls the function or uses it as a function | |
| 25700 | 167 reference (so that the argument and return types can be checked) |
| 27537 | 168 *E1091* *E1191* |
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169 If compilation fails it is not tried again on the next call, instead this |
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170 error is given: "E1091: Function is not compiled: {name}". |
| 24569 | 171 Compilation will fail when encountering a user command that has not been |
| 172 created yet. In this case you can call `execute()` to invoke it at runtime. > | |
| 173 def MyFunc() | |
| 174 execute('DefinedLater') | |
| 175 enddef | |
| 20552 | 176 |
| 177 `:def` has no options like `:function` does: "range", "abort", "dict" or | |
| 23164 | 178 "closure". A `:def` function always aborts on an error (unless `:silent!` was |
| 26708 | 179 used for the command or the error was caught a `:try` block), does not get a |
| 180 range passed cannot be a "dict" function, and can always be a closure. | |
| 25700 | 181 *vim9-no-dict-function* |
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182 Later classes will be added, which replaces the "dict function" mechanism. |
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183 For now you will need to pass the dictionary explicitly: > |
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184 def DictFunc(d: dict<any>, arg: string) |
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185 echo d[arg] |
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186 enddef |
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187 var d = {item: 'value', func: DictFunc} |
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188 d.func(d, 'item') |
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189 |
| 25836 | 190 You can call a legacy dict function though: > |
| 191 func Legacy() dict | |
| 192 echo self.value | |
| 193 endfunc | |
| 194 def CallLegacy() | |
| 195 var d = {func: Legacy, value: 'text'} | |
| 196 d.func() | |
| 197 enddef | |
| 27537 | 198 < *E1096* *E1174* *E1175* |
| 20241 | 199 The argument types and return type need to be specified. The "any" type can |
| 200 be used, type checking will then be done at runtime, like with legacy | |
| 201 functions. | |
| 27459 | 202 *E1106* |
| 21825 | 203 Arguments are accessed by name, without "a:", just like any other language. |
| 204 There is no "a:" dictionary or "a:000" list. | |
| 27537 | 205 *vim9-variable-arguments* *E1055* *E1160* *E1180* |
| 20241 | 206 Variable arguments are defined as the last argument, with a name and have a |
| 21825 | 207 list type, similar to TypeScript. For example, a list of numbers: > |
| 22171 | 208 def MyFunc(...itemlist: list<number>) |
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209 for item in itemlist |
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210 ... |
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211 |
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212 When a function argument is optional (it has a default value) passing `v:none` |
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213 as the argument results in using the default value. This is useful when you |
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214 want to specify a value for an argument that comes after an argument that |
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215 should use its default value. Example: > |
| 25973 | 216 def MyFunc(one = 'one', last = 'last') |
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217 ... |
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218 enddef |
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219 MyFunc(v:none, 'LAST') # first argument uses default value 'one' |
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220 < |
| 27537 | 221 *vim9-ignored-argument* *E1181* |
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222 The argument "_" (an underscore) can be used to ignore the argument. This is |
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223 most useful in callbacks where you don't need it, but do need to give an |
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224 argument to match the call. E.g. when using map() two arguments are passed, |
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225 the key and the value, to ignore the key: > |
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226 map(myList, (_, v) => v * 2) |
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227 There is no error for using the "_" argument multiple times. No type needs to |
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228 be given. |
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229 |
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230 |
| 20241 | 231 Functions and variables are script-local by default ~ |
| 20856 | 232 *vim9-scopes* |
| 20115 | 233 When using `:function` or `:def` to specify a new function at the script level |
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234 in a Vim9 script, the function is local to the script. Like prefixing "s:" in |
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235 legacy script. To define a global function or variable the "g:" prefix must |
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236 be used. For functions in a script that is to be imported and in an autoload |
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237 script "export" needs to be used. > |
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238 def ThisFunction() # script-local |
| 22171 | 239 def g:ThatFunction() # global |
| 27623 | 240 export def Function() # for import and import autoload |
| 27321 | 241 < *E1058* *E1075* |
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242 When using `:function` or `:def` to specify a nested function inside a `:def` |
| 26438 | 243 function and no namespace was given, this nested function is local to the code |
| 27903 | 244 block it is defined in. It cannot be used in `function()` with a string |
| 245 argument, pass the function reference itself: > | |
| 246 def Outer() | |
| 247 def Inner() | |
| 248 echo 'inner' | |
| 249 enddef | |
| 250 var Fok = function(Inner) # OK | |
| 251 var Fbad = function('Inner') # does not work | |
| 252 | |
| 253 It is not possible to define a script-local function. It is possible to | |
| 254 define a global function by using the "g:" prefix. | |
| 20115 | 255 |
| 256 When referring to a function and no "s:" or "g:" prefix is used, Vim will | |
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257 search for the function: |
| 22565 | 258 - in the function scope, in block scopes |
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259 - in the script scope, possibly imported |
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260 |
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261 Since a script-local function reference can be used without "s:" the name must |
| 24278 | 262 start with an upper case letter even when using the "s:" prefix. In legacy |
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263 script "s:funcref" could be used, because it could not be referred to with |
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264 "funcref". In Vim9 script it can, therefore "s:Funcref" must be used to avoid |
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265 that the name interferes with builtin functions. |
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266 *vim9-s-namespace* |
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267 The use of the "s:" prefix is not supported at the Vim9 script level. All |
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268 functions and variables without a prefix are script-local. |
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269 |
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270 In :def functions the use of "s:" depends on the script: Script-local |
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271 variables and functions in a legacy script do use "s:", while in a Vim9 script |
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272 they do not use "s:". This matches what you see in the rest of the file. |
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273 |
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274 In legacy functions the use of "s:" for script items is required, as before. |
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275 |
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276 In all cases the function must be defined before used. That is when it is |
| 22723 | 277 called, when `:defcompile` causes it to be compiled, or when code that calls |
| 278 it is being compiled (to figure out the return type). | |
| 20241 | 279 |
| 21676 | 280 The result is that functions and variables without a namespace can usually be |
| 20241 | 281 found in the script, either defined there or imported. Global functions and |
| 21676 | 282 variables could be defined anywhere (good luck finding out where!). |
| 27459 | 283 *E1102* |
| 21825 | 284 Global functions can still be defined and deleted at nearly any time. In |
| 20317 | 285 Vim9 script script-local functions are defined once when the script is sourced |
| 20552 | 286 and cannot be deleted or replaced. |
| 20115 | 287 |
| 23305 | 288 When compiling a function and a function call is encountered for a function |
| 289 that is not (yet) defined, the |FuncUndefined| autocommand is not triggered. | |
| 290 You can use an autoload function if needed, or call a legacy function and have | |
| 291 |FuncUndefined| triggered there. | |
| 292 | |
| 20115 | 293 |
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294 Reloading a Vim9 script clears functions and variables by default ~ |
| 27537 | 295 *vim9-reload* *E1149* *E1150* |
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296 When loading a legacy Vim script a second time nothing is removed, the |
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297 commands will replace existing variables and functions and create new ones. |
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298 |
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299 When loading a Vim9 script a second time all existing script-local functions |
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300 and variables are deleted, thus you start with a clean slate. This is useful |
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301 if you are developing a plugin and want to try a new version. If you renamed |
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302 something you don't have to worry about the old name still hanging around. |
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303 |
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304 If you do want to keep items, use: > |
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305 vim9script noclear |
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306 |
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307 You want to use this in scripts that use a `finish` command to bail out at |
| 27804 | 308 some point when loaded again. E.g. when a buffer local option is set to a |
| 309 function, the function does not need to be defined more than once: > | |
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310 vim9script noclear |
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311 setlocal completefunc=SomeFunc |
| 27804 | 312 if exists('*SomeFunc') |
| 27623 | 313 finish |
| 314 endif | |
| 27804 | 315 def SomeFunc() |
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316 .... |
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317 |
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318 |
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319 Variable declarations with :var, :final and :const ~ |
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320 *vim9-declaration* *:var* *E1079* |
| 27459 | 321 *E1017* *E1020* *E1054* *E1087* *E1108* *E1124* |
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322 Local variables need to be declared with `:var`. Local constants need to be |
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323 declared with `:final` or `:const`. We refer to both as "variables" in this |
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324 section. |
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325 |
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326 Variables can be local to a script, function or code block: > |
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327 vim9script |
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328 var script_var = 123 |
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329 def SomeFunc() |
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330 var func_var = script_var |
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331 if cond |
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332 var block_var = func_var |
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333 ... |
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334 |
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335 The variables are only visible in the block where they are defined and nested |
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336 blocks. Once the block ends the variable is no longer accessible: > |
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337 if cond |
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338 var inner = 5 |
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339 else |
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340 var inner = 0 |
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341 endif |
| 22171 | 342 echo inner # Error! |
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343 |
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344 The declaration must be done earlier: > |
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345 var inner: number |
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346 if cond |
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347 inner = 5 |
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348 else |
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349 inner = 0 |
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350 endif |
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351 echo inner |
| 27459 | 352 < *E1025* *E1128* |
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353 To intentionally hide a variable from code that follows, a block can be |
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354 used: > |
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355 { |
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356 var temp = 'temp' |
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357 ... |
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358 } |
| 22171 | 359 echo temp # Error! |
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360 |
| 25402 | 361 This is especially useful in a user command: > |
| 362 | |
| 363 command -range Rename { | |
| 25619 | 364 var save = @a |
| 365 @a = 'some expression' | |
| 366 echo 'do something with ' .. @a | |
| 367 @a = save | |
| 368 } | |
| 25402 | 369 |
| 370 And with autocommands: > | |
| 371 | |
| 372 au BufWritePre *.go { | |
| 25619 | 373 var save = winsaveview() |
| 374 silent! exe ':%! some formatting command' | |
| 375 winrestview(save) | |
| 376 } | |
| 25402 | 377 |
| 378 Although using a :def function probably works better. | |
| 27537 | 379 *E1022* *E1103* *E1130* *E1131* *E1133* |
| 380 *E1134* *E1235* | |
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381 Declaring a variable with a type but without an initializer will initialize to |
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382 false (for bool), empty (for string, list, dict, etc.) or zero (for number, |
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383 any, etc.). This matters especially when using the "any" type, the value will |
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384 default to the number zero. |
| 27321 | 385 *E1016* *E1052* *E1066* |
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386 In Vim9 script `:let` cannot be used. An existing variable is assigned to |
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387 without any command. The same for global, window, tab, buffer and Vim |
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388 variables, because they are not really declared. Those can also be deleted |
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389 with `:unlet`. |
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390 *E1065* |
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391 You cannot use `:va` to declare a variable, it must be written with the full |
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392 name `:var`. Just to make sure it is easy to read. |
| 27537 | 393 *E1178* |
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394 `:lockvar` does not work on local variables. Use `:const` and `:final` |
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395 instead. |
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396 |
| 25619 | 397 The `exists()` and `exists_compiled()` functions do not work on local variables |
| 398 or arguments. | |
| 27537 | 399 *E1006* *E1041* *E1167* *E1168* *E1213* |
| 24024 | 400 Variables, functions and function arguments cannot shadow previously defined |
| 401 or imported variables and functions in the same script file. | |
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402 Variables may shadow Ex commands, rename the variable if needed. |
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403 |
| 24387 | 404 Global variables must be prefixed with "g:", also at the script level. > |
| 19968 | 405 vim9script |
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406 var script_local = 'text' |
| 21499 | 407 g:global = 'value' |
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408 var Funcref = g:ThatFunction |
| 19968 | 409 |
| 27492 | 410 Global functions must be prefixed with "g:": > |
| 24387 | 411 vim9script |
| 412 def g:GlobalFunc(): string | |
| 413 return 'text' | |
| 414 enddef | |
| 27492 | 415 echo g:GlobalFunc() |
| 24387 | 416 The "g:" prefix is not needed for auto-load functions. |
| 417 | |
| 25619 | 418 *vim9-function-defined-later* |
| 419 Although global functions can be called without the "g:" prefix, they must | |
| 420 exist when compiled. By adding the "g:" prefix the function can be defined | |
| 421 later. Example: > | |
| 422 def CallPluginFunc() | |
| 423 if exists('g:loaded_plugin') | |
| 424 g:PluginFunc() | |
| 425 endif | |
| 426 enddef | |
| 427 | |
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428 If you do it like this, you get an error at compile time that "PluginFunc" |
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429 does not exist, even when "g:loaded_plugin" does not exist: > |
| 25619 | 430 def CallPluginFunc() |
| 431 if exists('g:loaded_plugin') | |
| 432 PluginFunc() # Error - function not found | |
| 433 endif | |
| 434 enddef | |
| 435 | |
| 436 You can use exists_compiled() to avoid the error, but then the function would | |
| 437 not be called, even when "g:loaded_plugin" is defined later: > | |
| 438 def CallPluginFunc() | |
| 439 if exists_compiled('g:loaded_plugin') | |
| 440 PluginFunc() # Function may never be called | |
| 441 endif | |
| 442 enddef | |
| 443 | |
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444 Since `&opt = value` is now assigning a value to option "opt", ":&" cannot be |
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445 used to repeat a `:substitute` command. |
| 24468 | 446 *vim9-unpack-ignore* |
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447 For an unpack assignment the underscore can be used to ignore a list item, |
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448 similar to how a function argument can be ignored: > |
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449 [a, _, c] = theList |
| 24468 | 450 To ignore any remaining items: > |
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451 [a, b; _] = longList |
| 27804 | 452 < *E1163* *E1080* |
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453 Declaring more than one variable at a time, using the unpack notation, is |
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454 possible. Each variable can have a type or infer it from the value: > |
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455 var [v1: number, v2] = GetValues() |
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456 Use this only when there is a list with values, declaring one variable per |
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457 line is much easier to read and change later. |
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458 |
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459 |
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460 Constants ~ |
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461 *vim9-const* *vim9-final* |
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462 How constants work varies between languages. Some consider a variable that |
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463 can't be assigned another value a constant. JavaScript is an example. Others |
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464 also make the value immutable, thus when a constant uses a list, the list |
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465 cannot be changed. In Vim9 we can use both. |
| 27321 | 466 *E1021* |
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467 `:const` is used for making both the variable and the value a constant. Use |
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468 this for composite structures that you want to make sure will not be modified. |
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469 Example: > |
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470 const myList = [1, 2] |
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471 myList = [3, 4] # Error! |
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472 myList[0] = 9 # Error! |
| 24024 | 473 myList->add(3) # Error! |
| 27459 | 474 < *:final* *E1125* |
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475 `:final` is used for making only the variable a constant, the value can be |
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476 changed. This is well known from Java. Example: > |
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477 final myList = [1, 2] |
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478 myList = [3, 4] # Error! |
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479 myList[0] = 9 # OK |
| 24024 | 480 myList->add(3) # OK |
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481 |
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482 It is common to write constants as ALL_CAPS, but you don't have to. |
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483 |
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484 The constant only applies to the value itself, not what it refers to. > |
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485 final females = ["Mary"] |
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486 const NAMES = [["John", "Peter"], females] |
|
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487 NAMES[0] = ["Jack"] # Error! |
|
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488 NAMES[0][0] = "Jack" # Error! |
|
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489 NAMES[1] = ["Emma"] # Error! |
| 23573 | 490 NAMES[1][0] = "Emma" # OK, now females[0] == "Emma" |
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491 |
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492 |
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493 Omitting :call and :eval ~ |
| 27537 | 494 *E1190* |
|
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495 Functions can be called without `:call`: > |
| 22171 | 496 writefile(lines, 'file') |
| 19303 | 497 Using `:call` is still possible, but this is discouraged. |
|
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498 |
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499 A method call without `eval` is possible, so long as the start is an |
|
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500 identifier or can't be an Ex command. For a function either "(" or "->" must |
|
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501 be following, without a line break. Examples: > |
|
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502 myList->add(123) |
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503 g:myList->add(123) |
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504 [1, 2, 3]->Process() |
|
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505 {a: 1, b: 2}->Process() |
|
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506 "foobar"->Process() |
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507 ("foobar")->Process() |
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508 'foobar'->Process() |
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509 ('foobar')->Process() |
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510 |
| 21825 | 511 In the rare case there is ambiguity between a function name and an Ex command, |
| 21676 | 512 prepend ":" to make clear you want to use the Ex command. For example, there |
| 513 is both the `:substitute` command and the `substitute()` function. When the | |
| 514 line starts with `substitute(` this will use the function. Prepend a colon to | |
| 515 use the command instead: > | |
|
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516 :substitute(pattern (replacement ( |
|
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517 |
| 25402 | 518 If the expression starts with "!" this is interpreted as a shell command, not |
| 519 negation of a condition. Thus this is a shell command: > | |
| 520 !shellCommand->something | |
| 25700 | 521 Put the expression in parentheses to use the "!" for negation: > |
| 25402 | 522 (!expression)->Method() |
| 523 | |
|
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524 Note that while variables need to be defined before they can be used, |
| 21825 | 525 functions can be called before being defined. This is required to allow |
| 526 for cyclic dependencies between functions. It is slightly less efficient, | |
|
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527 since the function has to be looked up by name. And a typo in the function |
|
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528 name will only be found when the function is called. |
|
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529 |
|
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530 |
| 19968 | 531 Omitting function() ~ |
| 532 | |
| 533 A user defined function can be used as a function reference in an expression | |
| 534 without `function()`. The argument types and return type will then be checked. | |
| 535 The function must already have been defined. > | |
| 536 | |
|
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537 var Funcref = MyFunction |
| 19968 | 538 |
| 539 When using `function()` the resulting type is "func", a function with any | |
| 25161 | 540 number of arguments and any return type (including void). The function can be |
| 26708 | 541 defined later if the argument is in quotes. |
| 19968 | 542 |
| 543 | |
|
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patch 8.2.2222: Vim9: cannot keep script variables when reloading
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|
544 Lambda using => instead of -> ~ |
| 24387 | 545 *vim9-lambda* |
|
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Bram Moolenaar <Bram@vim.org>
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546 In legacy script there can be confusion between using "->" for a method call |
|
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|
547 and for a lambda. Also, when a "{" is found the parser needs to figure out if |
|
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548 it is the start of a lambda or a dictionary, which is now more complicated |
|
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549 because of the use of argument types. |
|
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550 |
|
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551 To avoid these problems Vim9 script uses a different syntax for a lambda, |
|
24888
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patch 8.2.2982: Vim9: future commands are not reserved yet
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552 which is similar to JavaScript: > |
|
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553 var Lambda = (arg) => expression |
| 27537 | 554 var Lambda = (arg): type => expression |
| 555 < *E1157* | |
|
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556 No line break is allowed in the arguments of a lambda up to and including the |
| 25056 | 557 "=>" (so that Vim can tell the difference between an expression in parentheses |
| 24911 | 558 and lambda arguments). This is OK: > |
|
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|
559 filter(list, (k, v) => |
|
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560 v > 0) |
|
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561 This does not work: > |
|
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562 filter(list, (k, v) |
|
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563 => v > 0) |
|
23392
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patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
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564 This also does not work: > |
|
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565 filter(list, (k, |
|
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|
566 v) => v > 0) |
|
23392
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|
567 But you can use a backslash to concatenate the lines before parsing: > |
|
517fca70e084
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|
568 filter(list, (k, |
|
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|
569 \ v) |
|
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patch 8.2.2239: Vim9: concatenating lines with backslash is inconvenient
Bram Moolenaar <Bram@vim.org>
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|
570 \ => v > 0) |
| 27537 | 571 < *vim9-lambda-arguments* *E1172* |
|
24408
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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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diff
changeset
|
572 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
|
573 there was no way to warn for not using them. In Vim9 script the number of |
|
96e0b898d5b4
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|
574 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
|
575 arguments, use "..._", which makes the function accept |
|
96e0b898d5b4
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|
576 |vim9-variable-arguments|. Example: > |
|
96e0b898d5b4
patch 8.2.2744: Vim9: no way to explicitly ignore an argument
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|
577 var Callback = (..._) => 'anything' |
|
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|
578 echo Callback(1, 2, 3) # displays "anything" |
|
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|
579 |
| 27537 | 580 < *inline-function* *E1171* |
|
23318
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|
581 Additionally, a lambda can contain statements in {}: > |
|
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|
582 var Lambda = (arg) => { |
|
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changeset
|
583 g:was_called = 'yes' |
|
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Bram Moolenaar <Bram@vim.org>
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|
584 return expression |
|
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|
585 } |
| 24387 | 586 This can be useful for a timer, for example: > |
| 587 var count = 0 | |
| 588 var timer = timer_start(500, (_) => { | |
| 589 count += 1 | |
| 590 echom 'Handler called ' .. count | |
| 591 }, {repeat: 3}) | |
| 592 | |
|
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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
|
593 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
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changeset
|
594 characters, e.g.: > |
|
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Bram Moolenaar <Bram@vim.org>
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|
595 var d = mapnew(dict, (k, v): string => { |
|
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patch 8.2.2677: Vim9: cannot use only some of the default arguments
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|
596 return 'value' |
|
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597 }) |
|
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Bram Moolenaar <Bram@vim.org>
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|
598 No command can follow the "{", only a comment can be used there. |
|
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patch 8.2.2677: Vim9: cannot use only some of the default arguments
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|
599 |
| 27321 | 600 *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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changeset
|
601 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
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|
602 syntax will be used. |
|
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changeset
|
603 |
| 26591 | 604 If the statements include a dictionary, its closing bracket must not be |
| 605 written at the start of a line. Otherwise, it would be parsed as the end of | |
| 606 the block. This does not work: > | |
| 607 command NewCommand { | |
|
26612
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changeset
|
608 g:mydict = { |
| 26591 | 609 'key': 'value', |
| 610 } # ERROR: will be recognized as the end of the block | |
| 611 } | |
| 612 Put the '}' after the last item to avoid this: > | |
| 613 command NewCommand { | |
|
26612
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changeset
|
614 g:mydict = { |
| 26591 | 615 'key': 'value' } |
| 616 } | |
| 617 | |
|
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
|
618 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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changeset
|
619 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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changeset
|
620 "{". Unfortunately this means using "() => { command }" does not work, line |
|
cabed216cc2f
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|
621 breaks are always required. |
|
23318
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|
622 |
| 23737 | 623 *vim9-curly* |
|
23358
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patch 8.2.2222: Vim9: cannot keep script variables when reloading
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|
624 To avoid the "{" of a dictionary literal to be recognized as a statement block |
| 24024 | 625 wrap it in parentheses: > |
|
23358
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|
626 var Lambda = (arg) => ({key: 42}) |
|
23318
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|
627 |
| 23737 | 628 Also when confused with the start of a command block: > |
| 629 ({ | |
| 630 key: value | |
| 631 })->method() | |
| 632 | |
|
23318
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|
633 |
|
19999
844c7646f61b
patch 8.2.0555: Vim9: line continuation is not always needed
Bram Moolenaar <Bram@vim.org>
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changeset
|
634 Automatic line continuation ~ |
| 27459 | 635 *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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changeset
|
636 In many cases it is obvious that an expression continues on the next line. In |
|
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637 those cases there is no need to prefix the line with a backslash (see |
|
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638 |line-continuation|). For example, when a list spans multiple lines: > |
|
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639 var mylist = [ |
|
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640 'one', |
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641 'two', |
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642 ] |
|
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643 And when a dict spans multiple lines: > |
|
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644 var mydict = { |
|
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645 one: 1, |
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646 two: 2, |
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647 } |
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648 With a function call: > |
|
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649 var result = Func( |
|
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650 arg1, |
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651 arg2 |
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652 ) |
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653 |
|
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654 For binary operators in expressions not in [], {} or () a line break is |
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655 possible just before or after the operator. For example: > |
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656 var text = lead |
|
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657 .. middle |
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658 .. end |
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659 var total = start + |
| 23573 | 660 end - |
|
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661 correction |
|
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662 var result = positive |
|
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663 ? PosFunc(arg) |
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664 : NegFunc(arg) |
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665 |
| 21499 | 666 For a method call using "->" and a member using a dot, a line break is allowed |
| 667 before it: > | |
|
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668 var result = GetBuilder() |
| 20965 | 669 ->BuilderSetWidth(333) |
| 670 ->BuilderSetHeight(777) | |
| 671 ->BuilderBuild() | |
|
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672 var result = MyDict |
| 21499 | 673 .member |
| 20965 | 674 |
|
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675 For commands that have an argument that is a list of commands, the | character |
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676 at the start of the line indicates line continuation: > |
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677 autocmd BufNewFile *.match if condition |
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678 | echo 'match' |
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679 | endif |
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680 |
| 25973 | 681 Note that this means that in heredoc the first line cannot start with a bar: > |
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682 var lines =<< trim END |
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683 | this doesn't work |
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684 END |
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685 Either use an empty line at the start or do not use heredoc. Or temporarily |
|
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686 add the "C" flag to 'cpoptions': > |
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687 set cpo+=C |
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688 var lines =<< trim END |
| 25973 | 689 | this works |
|
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690 END |
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691 set cpo-=C |
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692 If the heredoc is inside a function 'cpoptions' must be set before :def and |
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693 restored after the :enddef. |
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694 |
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695 In places where line continuation with a backslash is still needed, such as |
| 25161 | 696 splitting up a long Ex command, comments can start with '#\ ': > |
| 697 syn region Text | |
|
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698 \ start='foo' |
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699 #\ comment |
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700 \ end='bar' |
| 25161 | 701 Like with legacy script '"\ ' is used. This is also needed when line |
| 702 continuation is used without a backslash and a line starts with a bar: > | |
| 703 au CursorHold * echom 'BEFORE bar' | |
| 704 #\ some comment | |
| 705 | echom 'AFTER bar' | |
| 706 < | |
| 707 *E1050* | |
|
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|
708 To make it possible for the operator at the start of the line to be |
|
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|
709 recognized, it is required to put a colon before a range. This example will |
|
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patch 8.2.2982: Vim9: future commands are not reserved yet
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|
710 add "start" and print: > |
|
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|
711 var result = start |
|
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|
712 + print |
| 21250 | 713 Like this: > |
|
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patch 8.2.1744: Vim9: using ":const!" is weird
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changeset
|
714 var result = start + print |
| 21250 | 715 |
|
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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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|
716 This will assign "start" and print a line: > |
|
22391
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|
717 var result = start |
|
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Bram Moolenaar <Bram@vim.org>
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|
718 :+ print |
|
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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
|
719 |
| 27321 | 720 After the range an Ex command must follow. Without the colon you can call a |
| 721 function without `:call`, but after a range you do need it: > | |
| 722 MyFunc() | |
| 723 :% call MyFunc() | |
| 724 | |
| 23047 | 725 Note that the colon is not required for the |+cmd| argument: > |
| 726 edit +6 fname | |
| 727 | |
|
20015
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patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
parents:
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changeset
|
728 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
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parents:
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|
729 arguments: > |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
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diff
changeset
|
730 def MyFunc( |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
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diff
changeset
|
731 text: string, |
|
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Bram Moolenaar <Bram@vim.org>
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changeset
|
732 separator = '-' |
|
c001ee73519a
patch 8.2.0563: Vim9: cannot split a function line
Bram Moolenaar <Bram@vim.org>
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733 ): string |
|
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patch 8.2.0563: Vim9: cannot split a function line
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|
734 |
| 23305 | 735 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>
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changeset
|
736 has been made stricter. E.g., because of the error in the first line, the |
| 23305 | 737 second line is seen as a separate command: > |
| 738 popup_create(some invalid expression, { | |
| 739 exit_cb: Func}) | |
| 740 Now "exit_cb: Func})" is actually a valid command: save any changes to the | |
| 741 file "_cb: Func})" and exit. To avoid this kind of mistake in Vim9 script | |
| 742 there must be white space between most command names and the argument. | |
| 27459 | 743 *E1144* |
| 23305 | 744 |
| 23666 | 745 However, the argument of a command that is a command won't be recognized. For |
| 746 example, after "windo echo expr" a line break inside "expr" will not be seen. | |
| 747 | |
| 23305 | 748 |
| 21250 | 749 Notes: |
| 750 - "enddef" cannot be used at the start of a continuation line, it ends the | |
| 751 current function. | |
| 752 - No line break is allowed in the LHS of an assignment. Specifically when | |
| 753 unpacking a list |:let-unpack|. This is OK: > | |
| 22171 | 754 [var1, var2] = |
| 21250 | 755 Func() |
| 756 < This does not work: > | |
| 22171 | 757 [var1, |
| 21250 | 758 var2] = |
| 759 Func() | |
| 760 - No line break is allowed in between arguments of an `:echo`, `:execute` and | |
| 761 similar commands. This is OK: > | |
| 22171 | 762 echo [1, |
| 21250 | 763 2] [3, |
| 764 4] | |
| 765 < This does not work: > | |
| 22171 | 766 echo [1, 2] |
| 21250 | 767 [3, 4] |
|
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patch 8.2.2982: Vim9: future commands are not reserved yet
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|
768 - 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
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changeset
|
769 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
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|
770 those cases the line continuation with a backslash has to be used. |
|
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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
|
771 |
| 24569 | 772 |
| 773 White space ~ | |
| 27537 | 774 *E1004* *E1068* *E1069* *E1074* *E1127* *E1202* |
| 24569 | 775 Vim9 script enforces proper use of white space. This is no longer allowed: > |
| 776 var name=234 # Error! | |
| 777 var name= 234 # Error! | |
| 778 var name =234 # Error! | |
| 779 There must be white space before and after the "=": > | |
| 780 var name = 234 # OK | |
| 781 White space must also be put before the # that starts a comment after a | |
| 782 command: > | |
| 783 var name = 234# Error! | |
| 784 var name = 234 # OK | |
| 785 | |
| 786 White space is required around most operators. | |
| 787 | |
| 788 White space is required in a sublist (list slice) around the ":", except at | |
| 789 the start and end: > | |
| 790 otherlist = mylist[v : count] # v:count has a different meaning | |
| 791 otherlist = mylist[:] # make a copy of the List | |
| 792 otherlist = mylist[v :] | |
| 793 otherlist = mylist[: v] | |
| 794 | |
| 795 White space is not allowed: | |
| 796 - Between a function name and the "(": > | |
| 797 Func (arg) # Error! | |
| 798 Func | |
| 799 \ (arg) # Error! | |
| 800 Func | |
| 801 (arg) # Error! | |
| 802 Func(arg) # OK | |
| 803 Func( | |
| 804 arg) # OK | |
| 805 Func( | |
| 806 arg # OK | |
| 807 ) | |
| 27537 | 808 < *E1205* |
| 25700 | 809 White space is not allowed in a `:set` command between the option name and a |
| 810 following "&", "!", "<", "=", "+=", "-=" or "^=". | |
| 25402 | 811 |
| 24569 | 812 |
|
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Bram Moolenaar <Bram@vim.org>
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|
813 No curly braces expansion ~ |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
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|
814 |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
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changeset
|
815 |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:
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changeset
|
816 |
|
94eda51ba9ba
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Bram Moolenaar <Bram@vim.org>
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changeset
|
817 |
| 27537 | 818 Command modifiers are not ignored ~ |
| 819 *E1176* | |
| 820 Using a command modifier for a command that does not use it gives an error. | |
| 821 | |
| 822 | |
|
22936
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Bram Moolenaar <Bram@vim.org>
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|
823 Dictionary literals ~ |
| 27321 | 824 *vim9-literal-dict* *E1014* |
|
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
|
825 Traditionally Vim has supported dictionary literals with a {} syntax: > |
|
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
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diff
changeset
|
826 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
|
827 |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
828 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:
23047
diff
changeset
|
829 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
|
830 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
|
831 |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
832 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
|
833 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
|
834 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:
23047
diff
changeset
|
835 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
|
836 uses literal keys: > |
| 23666 | 837 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
|
838 |
|
23088
285cde4b8d0e
patch 8.2.2090: Vim9: dict does not accept a key in quotes
Bram Moolenaar <Bram@vim.org>
parents:
23047
diff
changeset
|
839 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
|
840 use another character, use a single or double quoted string: > |
| 23666 | 841 var dict = {'key with space': value} |
| 842 var dict = {"key\twith\ttabs": value} | |
| 843 var dict = {'': value} # empty key | |
| 27459 | 844 < *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
|
845 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
|
846 like in JavaScript: > |
| 23666 | 847 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
|
848 |
|
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
|
849 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
|
850 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
|
851 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
|
852 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
|
853 {'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
|
854 |
|
22936
00b0275ffe7f
patch 8.2.2015: Vim9: literal dict #{} is not like any other language
Bram Moolenaar <Bram@vim.org>
parents:
22723
diff
changeset
|
855 |
|
23978
54b2aa1f0d42
patch 8.2.2531: Vim9: the :k command is obscure
Bram Moolenaar <Bram@vim.org>
parents:
23974
diff
changeset
|
856 No :xit, :t, :k, :append, :change or :insert ~ |
| 27459 | 857 *E1100* |
|
21584
d0c76ce48326
patch 8.2.1342: Vim9: accidentally using "t" gives a confusing error
Bram Moolenaar <Bram@vim.org>
parents:
21550
diff
changeset
|
858 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
|
859 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
|
860 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
|
861 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
|
862 |
| 19303 | 863 |
| 864 Comparators ~ | |
| 865 | |
| 866 The 'ignorecase' option is not used for comparators that use strings. | |
| 27804 | 867 Thus "=~" works like "=~#". |
|
19181
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patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
868 |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
869 |
| 24569 | 870 Abort after error ~ |
| 871 | |
| 872 In legacy script, when an error is encountered, Vim continues to execute | |
| 873 following lines. This can lead to a long sequence of errors and need to type | |
| 874 CTRL-C to stop it. In Vim9 script execution of commands stops at the first | |
| 875 error. Example: > | |
| 876 vim9script | |
| 877 var x = does-not-exist | |
| 878 echo 'not executed' | |
| 879 | |
| 880 | |
| 23666 | 881 For loop ~ |
| 27537 | 882 *E1254* |
| 26438 | 883 The loop variable must not be declared yet: > |
| 26304 | 884 var i = 1 |
| 885 for i in [1, 2, 3] # Error! | |
| 886 | |
| 26438 | 887 It is possible to use a global variable though: > |
| 888 g:i = 1 | |
| 889 for g:i in [1, 2, 3] | |
| 890 echo g:i | |
| 891 endfor | |
| 892 | |
| 23666 | 893 Legacy Vim script has some tricks to make a for loop over a list handle |
| 894 deleting items at the current or previous item. In Vim9 script it just uses | |
| 895 the index, if items are deleted then items in the list will be skipped. | |
| 896 Example legacy script: > | |
| 897 let l = [1, 2, 3, 4] | |
| 898 for i in l | |
| 899 echo i | |
| 900 call remove(l, index(l, i)) | |
| 901 endfor | |
| 902 Would echo: | |
| 903 1 | |
| 904 2 | |
| 905 3 | |
| 906 4 | |
| 907 In compiled Vim9 script you get: | |
| 908 1 | |
| 909 3 | |
| 910 Generally, you should not change the list that is iterated over. Make a copy | |
| 911 first if needed. | |
| 912 | |
| 913 | |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
914 Conditions and expressions ~ |
| 27321 | 915 *vim9-boolean* |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
916 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
|
917 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
|
918 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
|
919 0 falsy falsy |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
920 1 truthy truthy |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
921 99 truthy Error! |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
922 "0" falsy Error! |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
923 "99" truthy Error! |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
924 "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
|
925 |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
926 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
|
927 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
|
928 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
|
929 |
|
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
930 type truthy when ~ |
| 23466 | 931 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
|
932 number non-zero |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
933 float non-zero |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
934 string non-empty |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
935 blob non-empty |
|
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
936 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
|
937 dictionary non-empty (different from JavaScript) |
| 19968 | 938 func when there is a function name |
| 23466 | 939 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
|
940 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
|
941 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
|
942 class when not NULL |
| 23466 | 943 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
|
944 |
|
22494
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
945 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
|
946 one: > |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
947 1 || false == true |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
948 0 || 1 == true |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
949 0 || false == false |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
950 1 && true == true |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
951 0 && 1 == false |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
952 8 || 0 Error! |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
953 'yes' && 0 Error! |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
954 [] || 99 Error! |
|
19181
94eda51ba9ba
patch 8.2.0149: maintaining a Vim9 branch separately is more work
Bram Moolenaar <Bram@vim.org>
parents:
diff
changeset
|
955 |
|
22494
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
956 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
|
957 result is a boolean. "!!" can be used to turn any value into boolean: > |
| 23573 | 958 !'yes' == false |
|
22500
ef8a3177edc1
patch 8.2.1798: Vim9: trinary operator condition is too permissive
Bram Moolenaar <Bram@vim.org>
parents:
22494
diff
changeset
|
959 !![] == false |
| 23573 | 960 !![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
|
961 |
|
4c21f7f6f9e3
patch 8.2.1795: Vim9: operators && and || have a confusing result
Bram Moolenaar <Bram@vim.org>
parents:
22441
diff
changeset
|
962 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
|
963 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
|
964 'hello ' .. 123 == 'hello 123' |
| 23466 | 965 '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
|
966 |
|
26769
30972227ac8d
patch 8.2.3913: help for expressions does not mention Vim9 syntax
Bram Moolenaar <Bram@vim.org>
parents:
26755
diff
changeset
|
967 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
|
968 should be used. |
| 27321 | 969 *false* *true* *null* *E1034* |
|
28002
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
970 In Vim9 script one can use the following predefined values: > |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
971 true |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
972 false |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
973 null |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
974 null_blob |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
975 null_channel |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
976 null_dict |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
977 null_function |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
978 null_job |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
changeset
|
979 null_list |
|
1012048eed26
patch 8.2.4526: Vim9: cannot set variables to a null value
Bram Moolenaar <Bram@vim.org>
parents:
27903
diff
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|
980 null_partial |
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981 null_string |
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982 `true` is the same as `v:true`, `false` the same as `v:false`, `null` the same |
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983 as `v:null`. |
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984 |
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985 While `null` has the type "special", the other "null_" types have the type |
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986 indicated by their name. Quite often a null value is handled the same as an |
|
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987 empty value, but not always. The values can be useful to clear a script-local |
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988 variable, since they cannot be deleted with `:unlet`. E.g.: > |
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989 var theJob = job_start(...) |
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990 # let the job do its work |
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991 theJob = null_job |
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992 |
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993 The values can also be useful as the default value for an argument: > |
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994 def MyFunc(b: blob = null_blob) |
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995 if b == null_blob |
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996 # b argument was not given |
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997 |
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998 When converting a boolean to a string `false` and `true` are used, not |
|
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999 `v:false` and `v:true` like in legacy script. `v:none` has no `none` |
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1000 replacement, it has no equivalent in other languages. |
|
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1001 |
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1002 Indexing a string with [idx] or taking a slice with [idx : idx] uses character |
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1003 indexes instead of byte indexes. Composing characters are included. |
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1004 Example: > |
| 21825 | 1005 echo 'bár'[1] |
| 1006 In legacy script this results in the character 0xc3 (an illegal byte), in Vim9 | |
| 1007 script this results in the string 'á'. | |
| 23573 | 1008 A negative index is counting from the end, "[-1]" is the last character. |
| 23666 | 1009 To exclude the last character use |slice()|. |
|
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1010 To count composing characters separately use |strcharpart()|. |
| 23573 | 1011 If the index is out of range then an empty string results. |
| 1012 | |
| 1013 In legacy script "++var" and "--var" would be silently accepted and have no | |
| 1014 effect. This is an error in Vim9 script. | |
| 1015 | |
| 1016 Numbers starting with zero are not considered to be octal, only numbers | |
| 1017 starting with "0o" are octal: "0o744". |scriptversion-4| | |
| 21825 | 1018 |
|
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1019 |
| 21093 | 1020 What to watch out for ~ |
| 1021 *vim9-gotchas* | |
| 1022 Vim9 was designed to be closer to often used programming languages, but at the | |
| 1023 same time tries to support the legacy Vim commands. Some compromises had to | |
| 1024 be made. Here is a summary of what might be unexpected. | |
| 1025 | |
| 1026 Ex command ranges need to be prefixed with a colon. > | |
| 23666 | 1027 -> legacy Vim: shifts the previous line to the right |
| 1028 ->func() Vim9: method call in a continuation line | |
| 1029 :-> Vim9: shifts the previous line to the right | |
| 21093 | 1030 |
| 23666 | 1031 %s/a/b legacy Vim: substitute on all lines |
| 21093 | 1032 x = alongname |
| 23666 | 1033 % another Vim9: modulo operator in a continuation line |
| 1034 :%s/a/b Vim9: substitute on all lines | |
| 1035 't legacy Vim: jump to mark t | |
| 1036 'text'->func() Vim9: method call | |
| 1037 :'t Vim9: jump to mark t | |
| 21093 | 1038 |
| 21676 | 1039 Some Ex commands can be confused with assignments in Vim9 script: > |
| 23666 | 1040 g:name = value # assignment |
|
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1041 :g:pattern:cmd # :global command |
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1042 |
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1043 To avoid confusion between a `:global` or `:substitute` command and an |
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1044 expression or assignment, a few separators cannot be used when these commands |
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1045 are abbreviated to a single character: ':', '-' and '.'. > |
| 23666 | 1046 g:pattern:cmd # invalid command - ERROR |
|
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1047 s:pattern:repl # invalid command - ERROR |
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1048 g-pattern-cmd # invalid command - ERROR |
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1049 s-pattern-repl # invalid command - ERROR |
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1050 g.pattern.cmd # invalid command - ERROR |
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1051 s.pattern.repl # invalid command - ERROR |
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1052 |
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1053 Also, there cannot be a space between the command and the separator: > |
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1054 g /pattern/cmd # invalid command - ERROR |
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1055 s /pattern/repl # invalid command - ERROR |
| 21676 | 1056 |
| 21093 | 1057 Functions defined with `:def` compile the whole function. Legacy functions |
| 1058 can bail out, and the following lines are not parsed: > | |
| 1059 func Maybe() | |
| 1060 if !has('feature') | |
| 1061 return | |
| 1062 endif | |
| 1063 use-feature | |
| 1064 endfunc | |
| 1065 Vim9 functions are compiled as a whole: > | |
| 1066 def Maybe() | |
| 1067 if !has('feature') | |
| 1068 return | |
| 1069 endif | |
| 23573 | 1070 use-feature # May give a compilation error |
| 21093 | 1071 enddef |
| 1072 For a workaround, split it in two functions: > | |
| 1073 func Maybe() | |
| 1074 if has('feature') | |
| 23666 | 1075 call MaybeInner() |
| 21093 | 1076 endif |
| 1077 endfunc | |
| 1078 if has('feature') | |
| 1079 def MaybeInner() | |
| 1080 use-feature | |
| 1081 enddef | |
| 1082 endif | |
| 22171 | 1083 Or put the unsupported code inside an `if` with a constant expression that |
| 21991 | 1084 evaluates to false: > |
| 1085 def Maybe() | |
| 1086 if has('feature') | |
| 1087 use-feature | |
| 1088 endif | |
| 1089 enddef | |
| 25619 | 1090 The `exists_compiled()` function can also be used for this. |
| 1091 *vim9-user-command* | |
| 23666 | 1092 Another side effect of compiling a function is that the presence of a user |
| 23573 | 1093 command is checked at compile time. If the user command is defined later an |
| 1094 error will result. This works: > | |
| 1095 command -nargs=1 MyCommand echom <q-args> | |
| 1096 def Works() | |
| 1097 MyCommand 123 | |
| 1098 enddef | |
| 1099 This will give an error for "MyCommand" not being defined: > | |
| 1100 def Works() | |
| 1101 command -nargs=1 MyCommand echom <q-args> | |
| 1102 MyCommand 123 | |
| 1103 enddef | |
| 1104 A workaround is to invoke the command indirectly with `:execute`: > | |
| 1105 def Works() | |
| 1106 command -nargs=1 MyCommand echom <q-args> | |
| 1107 execute 'MyCommand 123' | |
| 1108 enddef | |
| 1109 | |
| 21991 | 1110 Note that for unrecognized commands there is no check for "|" and a following |
| 1111 command. This will give an error for missing `endif`: > | |
| 1112 def Maybe() | |
| 1113 if has('feature') | use-feature | endif | |
| 1114 enddef | |
| 21093 | 1115 |
| 23305 | 1116 Other differences ~ |
| 1117 | |
| 1118 Patterns are used like 'magic' is set, unless explicitly overruled. | |
| 1119 The 'edcompatible' option value is not used. | |
| 1120 The 'gdefault' option value is not used. | |
| 1121 | |
| 24387 | 1122 You may also find this wiki useful. It was written by an early adopter of |
| 24103 | 1123 Vim9 script: https://github.com/lacygoill/wiki/blob/master/vim/vim9.md |
| 23305 | 1124 |
| 25056 | 1125 *:++* *:--* |
| 1126 The ++ and -- commands have been added. They are very similar to adding or | |
| 1127 subtracting one: > | |
| 1128 ++var | |
| 1129 var += 1 | |
| 1130 --var | |
| 1131 var -= 1 | |
| 1132 | |
| 1133 Using ++var or --var in an expression is not supported yet. | |
| 1134 | |
|
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1135 ============================================================================== |
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1136 |
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1137 3. New style functions *fast-functions* |
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1138 |
| 27321 | 1139 *:def* *E1028* |
| 21825 | 1140 :def[!] {name}([arguments])[: {return-type}] |
|
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1141 Define a new function by the name {name}. The body of |
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1142 the function follows in the next lines, until the |
| 27321 | 1143 matching `:enddef`. *E1073* |
| 1144 *E1011* | |
| 1145 The {name} must be less than 100 bytes long. | |
| 1146 *E1003* *E1027* *E1056* *E1059* | |
| 1147 The type of value used with `:return` must match | |
| 1148 {return-type}. When {return-type} is omitted or is | |
| 1149 "void" the function is not expected to return | |
| 1150 anything. | |
| 27459 | 1151 *E1077* *E1123* |
|
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1152 {arguments} is a sequence of zero or more argument |
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1153 declarations. There are three forms: |
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1154 {name}: {type} |
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1155 {name} = {value} |
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1156 {name}: {type} = {value} |
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1157 The first form is a mandatory argument, the caller |
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1158 must always provide them. |
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1159 The second and third form are optional arguments. |
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1160 When the caller omits an argument the {value} is used. |
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1161 |
| 20856 | 1162 The function will be compiled into instructions when |
| 21499 | 1163 called, or when `:disassemble` or `:defcompile` is |
| 1164 used. Syntax and type errors will be produced at that | |
| 1165 time. | |
| 20856 | 1166 |
| 21499 | 1167 It is possible to nest `:def` inside another `:def` or |
| 1168 `:function` up to about 50 levels deep. | |
| 27459 | 1169 *E1117* |
|
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1170 [!] is used as with `:function`. Note that |
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1171 script-local functions cannot be deleted or redefined |
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1172 later in Vim9 script. They can only be removed by |
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1173 reloading the same script. |
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1174 |
| 27537 | 1175 *:enddef* *E1057* *E1152* *E1173* |
| 21499 | 1176 :enddef End of a function defined with `:def`. It should be on |
| 1177 a line by its own. | |
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1178 |
| 24387 | 1179 You may also find this wiki useful. It was written by an early adopter of |
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1180 Vim9 script: https://github.com/lacygoill/wiki/blob/master/vim/vim9.md |
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1181 |
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1182 If the script the function is defined in is Vim9 script, then script-local |
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1183 variables can be accessed without the "s:" prefix. They must be defined |
| 20856 | 1184 before the function is compiled. If the script the function is defined in is |
| 1185 legacy script, then script-local variables must be accessed with the "s:" | |
| 24387 | 1186 prefix if they do not exist at the time of compiling. |
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1187 |
| 20552 | 1188 *:defc* *:defcompile* |
| 1189 :defc[ompile] Compile functions defined in the current script that | |
| 1190 were not compiled yet. | |
| 1191 This will report errors found during the compilation. | |
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1192 |
| 19404 | 1193 *:disa* *:disassemble* |
| 1194 :disa[ssemble] {func} Show the instructions generated for {func}. | |
| 27321 | 1195 This is for debugging and testing. *E1061* |
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1196 Note that for command line completion of {func} you |
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1197 can prepend "s:" to find script-local functions. |
| 19404 | 1198 |
| 24911 | 1199 :disa[ssemble] profile {func} |
| 1200 Like `:disassemble` but with the instructions used for | |
| 23737 | 1201 profiling. |
| 1202 | |
| 24911 | 1203 :disa[ssemble] debug {func} |
| 1204 Like `:disassemble` but with the instructions used for | |
| 1205 debugging. | |
| 1206 | |
| 21250 | 1207 Limitations ~ |
| 1208 | |
| 1209 Local variables will not be visible to string evaluation. For example: > | |
|
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1210 def MapList(): list<string> |
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1211 var list = ['aa', 'bb', 'cc', 'dd'] |
| 21250 | 1212 return range(1, 2)->map('list[v:val]') |
| 1213 enddef | |
| 1214 | |
| 1215 The map argument is a string expression, which is evaluated without the | |
| 1216 function scope. Instead, use a lambda: > | |
|
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1217 def MapList(): list<string> |
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1218 var list = ['aa', 'bb', 'cc', 'dd'] |
| 25973 | 1219 return range(1, 2)->map((_, v) => list[v]) |
| 21250 | 1220 enddef |
| 1221 | |
|
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1222 For commands that are not compiled, such as `:edit`, backtick expansion can be |
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1223 used and it can use the local scope. Example: > |
|
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1224 def Replace() |
|
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1225 var fname = 'blah.txt' |
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1226 edit `=fname` |
| 25402 | 1227 enddef |
| 1228 | |
| 24278 | 1229 Closures defined in a loop will share the same context. For example: > |
| 1230 var flist: list<func> | |
| 25402 | 1231 for i in range(5) |
| 24278 | 1232 var inloop = i |
| 1233 flist[i] = () => inloop | |
| 1234 endfor | |
| 25402 | 1235 echo range(5)->map((i, _) => flist[i]()) |
| 1236 # Result: [4, 4, 4, 4, 4] | |
| 24278 | 1237 |
| 1238 The "inloop" variable will exist only once, all closures put in the list refer | |
| 25402 | 1239 to the same instance, which in the end will have the value 4. This is |
| 1240 efficient, also when looping many times. If you do want a separate context | |
| 1241 for each closure call a function to define it: > | |
| 1242 def GetClosure(i: number): func | |
| 1243 var infunc = i | |
| 1244 return () => infunc | |
| 24278 | 1245 enddef |
| 1246 | |
| 1247 var flist: list<func> | |
| 25402 | 1248 for i in range(5) |
| 1249 flist[i] = GetClosure(i) | |
| 24278 | 1250 endfor |
| 25402 | 1251 echo range(5)->map((i, _) => flist[i]()) |
| 1252 # Result: [0, 1, 2, 3, 4] | |
| 24278 | 1253 |
| 27537 | 1254 In some situations, especially when calling a Vim9 closure from legacy |
| 1255 context, the evaluation will fail. *E1248* | |
| 1256 | |
| 1257 | |
| 1258 Converting a function from legacy to Vim9 ~ | |
| 1259 *convert_legacy_function_to_vim9* | |
| 1260 These are the most changes that need to be made to convert a legacy function | |
| 1261 to a Vim9 function: | |
| 1262 | |
| 1263 - Change `func` or `function` to `def`. | |
| 1264 - Change `endfunc` or `endfunction` to `enddef`. | |
| 1265 - Add types to the function arguments. | |
| 1266 - If the function returns something, add the return type. | |
| 1267 - Change comments to start with # instead of ". | |
| 1268 | |
| 1269 For example, a legacy function: > | |
| 1270 func MyFunc(text) | |
| 1271 " function body | |
| 1272 endfunc | |
| 1273 < Becomes: > | |
| 1274 def MyFunc(text: string): number | |
| 1275 # function body | |
| 1276 enddef | |
| 1277 | |
| 1278 - Remove "a:" used for arguments. E.g.: > | |
| 1279 return len(a:text) | |
| 1280 < Becomes: > | |
| 1281 return len(text) | |
| 1282 | |
| 1283 - Change `let` used to declare a variable to `var`. | |
| 1284 - Remove `let` used to assign a value to a variable. This is for local | |
| 1285 variables already declared and b: w: g: and t: variables. | |
| 1286 | |
| 1287 For example, legacy function: > | |
| 1288 let lnum = 1 | |
| 1289 let lnum += 3 | |
| 1290 let b:result = 42 | |
| 1291 < Becomes: > | |
| 1292 var lnum = 1 | |
| 1293 lnum += 3 | |
| 1294 b:result = 42 | |
| 1295 | |
| 1296 - Insert white space in expressions where needed. | |
| 1297 - Change "." used for concatenation to "..". | |
| 1298 | |
| 1299 For example, legacy function: > | |
| 1300 echo line(1).line(2) | |
| 1301 < Becomes: > | |
| 1302 echo line(1) .. line(2) | |
| 1303 | |
| 1304 - line continuation does not always require a backslash: > | |
| 1305 echo ['one', | |
| 1306 \ 'two', | |
| 1307 \ 'three' | |
| 1308 \ ] | |
| 1309 < Becomes: > | |
| 1310 echo ['one', | |
| 1311 'two', | |
| 1312 'three' | |
| 1313 ] | |
| 1314 | |
|
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1315 ============================================================================== |
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1316 |
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1317 4. Types *vim9-types* |
| 27321 | 1318 *E1008* *E1009* *E1010* *E1012* |
| 1319 *E1013* *E1029* *E1030* | |
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1320 The following builtin types are supported: |
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1321 bool |
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1322 number |
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1323 float |
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1324 string |
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1325 blob |
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1326 list<{type}> |
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1327 dict<{type}> |
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1328 job |
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1329 channel |
| 19646 | 1330 func |
| 19968 | 1331 func: {type} |
|
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1332 func({type}, ...) |
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1333 func({type}, ...): {type} |
| 27321 | 1334 void |
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1335 |
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1336 Not supported yet: |
|
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1337 tuple<a: {type}, b: {type}, ...> |
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1338 |
| 25161 | 1339 These types can be used in declarations, but no simple value will actually |
| 27321 | 1340 have the "void" type. Trying to use a void (e.g. a function without a |
| 27537 | 1341 return value) results in error *E1031* *E1186* . |
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1342 |
|
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1343 There is no array type, use list<{type}> instead. For a list constant an |
|
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1344 efficient implementation is used that avoids allocating lot of small pieces of |
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1345 memory. |
| 27321 | 1346 *E1005* *E1007* |
|
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1347 A partial and function can be declared in more or less specific ways: |
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1348 func any kind of function reference, no type |
| 19968 | 1349 checking for arguments or return value |
| 25161 | 1350 func: void any number and type of arguments, no return |
| 1351 value | |
|
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1352 func: {type} any number and type of arguments with specific |
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1353 return type |
| 25161 | 1354 |
| 1355 func() function with no argument, does not return a | |
| 1356 value | |
| 1357 func(): void same | |
| 1358 func(): {type} function with no argument and return type | |
| 1359 | |
| 19968 | 1360 func({type}) function with argument type, does not return |
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1361 a value |
| 19968 | 1362 func({type}): {type} function with argument type and return type |
| 1363 func(?{type}) function with type of optional argument, does | |
| 1364 not return a value | |
| 1365 func(...{type}) function with type of variable number of | |
| 1366 arguments, does not return a value | |
| 1367 func({type}, ?{type}, ...{type}): {type} | |
| 1368 function with: | |
| 1369 - type of mandatory argument | |
| 1370 - type of optional argument | |
| 1371 - type of variable number of arguments | |
| 1372 - return type | |
|
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1373 |
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1374 If the return type is "void" the function does not return a value. |
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1375 |
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1376 The reference can also be a |Partial|, in which case it stores extra arguments |
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1377 and/or a dictionary, which are not visible to the caller. Since they are |
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1378 called in the same way the declaration is the same. |
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1379 |
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1380 Custom types can be defined with `:type`: > |
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1381 :type MyList list<string> |
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1382 Custom types must start with a capital letter, to avoid name clashes with |
|
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1383 builtin types added later, similarly to user functions. |
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1384 {not implemented yet} |
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1385 |
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1386 And classes and interfaces can be used as types: > |
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1387 :class MyClass |
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1388 :var mine: MyClass |
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1389 |
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1390 :interface MyInterface |
|
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1391 :var mine: MyInterface |
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1392 |
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1393 :class MyTemplate<Targ> |
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1394 :var mine: MyTemplate<number> |
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1395 :var mine: MyTemplate<string> |
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1396 |
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1397 :class MyInterface<Targ> |
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1398 :var mine: MyInterface<number> |
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1399 :var mine: MyInterface<string> |
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1400 {not implemented yet} |
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1401 |
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1402 |
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1403 Variable types and type casting ~ |
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1404 *variable-types* |
|
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1405 Variables declared in Vim9 script or in a `:def` function have a type, either |
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1406 specified explicitly or inferred from the initialization. |
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1407 |
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1408 Global, buffer, window and tab page variables do not have a specific type, the |
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1409 value can be changed at any time, possibly changing the type. Therefore, in |
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1410 compiled code the "any" type is assumed. |
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1411 |
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1412 This can be a problem when the "any" type is undesired and the actual type is |
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1413 expected to always be the same. For example, when declaring a list: > |
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1414 var l: list<number> = [1, g:two] |
| 23305 | 1415 At compile time Vim doesn't know the type of "g:two" and the expression type |
| 1416 becomes list<any>. An instruction is generated to check the list type before | |
| 1417 doing the assignment, which is a bit inefficient. | |
| 27459 | 1418 *type-casting* *E1104* |
| 23305 | 1419 To avoid this, use a type cast: > |
|
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1420 var l: list<number> = [1, <number>g:two] |
| 23305 | 1421 The compiled code will then only check that "g:two" is a number and give an |
| 1422 error if it isn't. This is called type casting. | |
|
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1423 |
|
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1424 The syntax of a type cast is: "<" {type} ">". There cannot be white space |
|
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1425 after the "<" or before the ">" (to avoid them being confused with |
|
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|
1426 smaller-than and bigger-than operators). |
|
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|
1427 |
|
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|
1428 The semantics is that, if needed, a runtime type check is performed. The |
|
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1429 value is not actually changed. If you need to change the type, e.g. to change |
|
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|
1430 it to a string, use the |string()| function. Or use |str2nr()| to convert a |
|
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|
1431 string to a number. |
|
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|
1432 |
|
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|
1433 |
|
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1434 Type inference ~ |
|
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1435 *type-inference* |
|
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1436 In general: Whenever the type is clear it can be omitted. For example, when |
|
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1437 declaring a variable and giving it a value: > |
|
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|
1438 var name = 0 # infers number type |
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1439 var name = 'hello' # infers string type |
|
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1440 |
|
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|
1441 The type of a list and dictionary comes from the common type of the values. |
|
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|
1442 If the values all have the same type, that type is used for the list or |
|
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|
1443 dictionary. If there is a mix of types, the "any" type is used. > |
|
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|
1444 [1, 2, 3] list<number> |
|
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|
1445 ['a', 'b', 'c'] list<string> |
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|
1446 [1, 'x', 3] list<any> |
|
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1447 |
| 25161 | 1448 The common type of function references, if they do not all have the same |
| 1449 number of arguments, uses "(...)" to indicate the number of arguments is not | |
| 1450 specified. For example: > | |
| 1451 def Foo(x: bool) | |
| 1452 enddef | |
| 1453 def Bar(x: bool, y: bool) | |
| 1454 enddef | |
| 1455 var funclist = [Foo, Bar] | |
| 1456 echo funclist->typename() | |
| 1457 Results in: | |
| 1458 list<func(...)> | |
| 1459 | |
| 24387 | 1460 For script-local variables in Vim9 script the type is checked, also when the |
| 1461 variable was declared in a legacy function. | |
| 1462 | |
| 27623 | 1463 When a type has been declared this is attached to a List or Dictionary. When |
| 27459 | 1464 later some expression attempts to change the type an error will be given: > |
| 1465 var ll: list<number> = [1, 2, 3] | |
| 27492 | 1466 ll->extend(['x']) # Error, 'x' is not a number |
| 27459 | 1467 |
| 27623 | 1468 If the type is not declared then it is allowed to change: > |
| 27492 | 1469 [1, 2, 3]->extend(['x']) # result: [1, 2, 3, 'x'] |
| 27459 | 1470 |
| 27623 | 1471 For a variable declaration an inferred type matters: > |
| 1472 var ll = [1, 2, 3] | |
| 1473 ll->extend(['x']) # Error, 'x' is not a number | |
| 1474 That is because the declaration looks like a list of numbers, thus is | |
| 1475 equivalent to: > | |
| 1476 var ll: list<number> = [1, 2, 3] | |
| 1477 If you do want a more permissive list you need to declare the type: > | |
| 1478 var ll: list<any = [1, 2, 3] | |
| 1479 ll->extend(['x']) # OK | |
| 1480 | |
| 21991 | 1481 |
|
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1482 Stricter type checking ~ |
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1483 *type-checking* |
| 21991 | 1484 In legacy Vim script, where a number was expected, a string would be |
| 1485 automatically converted to a number. This was convenient for an actual number | |
| 24387 | 1486 such as "123", but leads to unexpected problems (and no error message) if the |
| 21991 | 1487 string doesn't start with a number. Quite often this leads to hard-to-find |
| 27804 | 1488 bugs. e.g.: > |
| 1489 echo 123 == '123' | |
| 1490 < 1 ~ | |
| 1491 With an accidental space: > | |
| 1492 echo 123 == ' 123' | |
| 1493 < 0 ~ | |
| 27537 | 1494 *E1206* *E1210* *E1212* |
| 21991 | 1495 In Vim9 script this has been made stricter. In most places it works just as |
| 27804 | 1496 before if the value used matches the expected type. There will sometimes be |
| 22171 | 1497 an error, thus breaking backwards compatibility. For example: |
| 21991 | 1498 - Using a number other than 0 or 1 where a boolean is expected. *E1023* |
| 25161 | 1499 - Using a string value when setting a number option. |
| 27459 | 1500 - Using a number where a string is expected. *E1024* *E1105* |
| 21991 | 1501 |
| 25973 | 1502 One consequence is that the item type of a list or dict given to |map()| must |
| 27804 | 1503 not change, if the type was declared. This will give an error in Vim9 |
| 1504 script: > | |
| 1505 var mylist: list<number> = [1, 2, 3] | |
| 1506 echo map(mylist, (i, v) => 'item ' .. i) | |
| 1507 < E1012: Type mismatch; expected number but got string in map() ~ | |
| 25161 | 1508 |
| 27804 | 1509 Instead use |mapnew()|, it creates a new list: > |
| 1510 var mylist: list<number> = [1, 2, 3] | |
| 1511 echo mapnew(mylist, (i, v) => 'item ' .. i) | |
| 1512 < ['item 0', 'item 1', 'item 2'] ~ | |
| 1513 | |
| 1514 If the item type was not declared or determined to be "any" it can change to a | |
| 1515 more specific type. E.g. when a list of mixed types gets changed to a list of | |
| 1516 strings: > | |
| 25161 | 1517 var mylist = [1, 2.0, '3'] |
| 1518 # typename(mylist) == "list<any>" | |
| 1519 map(mylist, (i, v) => 'item ' .. i) | |
| 1520 # typename(mylist) == "list<string>", no error | |
| 27804 | 1521 |
| 1522 There is a subtle difference between using a list constant directly and | |
|
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1523 through a variable declaration. Because of type inference, when using a list |
| 27804 | 1524 constant to initialize a variable, this also sets the declared type: > |
| 1525 var mylist = [1, 2, 3] | |
| 1526 # typename(mylist) == "list<number>" | |
| 1527 echo map(mylist, (i, v) => 'item ' .. i) # Error! | |
| 1528 | |
| 1529 When using the list constant directly, the type is not declared and is allowed | |
| 1530 to change: > | |
| 1531 echo map([1, 2, 3], (i, v) => 'item ' .. i) # OK | |
| 1532 | |
| 1533 The reasoning behind this is that when a type is declared and the list is | |
| 1534 passed around and changed, the declaration must always hold. So that you can | |
| 1535 rely on the type to match the declared type. For a constant this is not | |
| 1536 needed. | |
| 1537 | |
| 1538 *E1158* | |
| 24024 | 1539 Same for |extend()|, use |extendnew()| instead, and for |flatten()|, use |
| 27804 | 1540 |flattennew()| instead. Since |flatten()| is intended to always change the |
| 1541 type, it can not be used in Vim9 script. | |
| 1542 | |
| 27537 | 1543 *E1211* *E1217* *E1218* *E1219* *E1220* *E1221* |
| 1544 *E1222* *E1223* *E1224* *E1225* *E1226* *E1227* | |
| 1545 *E1228* *E1238* *E1250* *E1251* *E1252* *E1253* | |
| 1546 *E1256* | |
| 1547 Types are checked for most builtin functions to make it easier to spot | |
| 1548 mistakes. | |
| 23573 | 1549 |
|
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1550 ============================================================================== |
|
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1551 |
|
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1552 5. Namespace, Import and Export |
|
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1553 *vim9script* *vim9-export* *vim9-import* |
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1554 |
| 27162 | 1555 A Vim9 script can be written to be imported. This means that some items are |
| 1556 intentionally exported, made available to other scripts. When the exporting | |
| 1557 script is imported in another script, these exported items can then be used in | |
| 1558 that script. All the other items remain script-local in the exporting script | |
| 1559 and cannot be accessed by the importing script. | |
| 27036 | 1560 |
| 1561 This mechanism exists for writing a script that can be sourced (imported) by | |
| 1562 other scripts, while making sure these other scripts only have access to what | |
| 1563 you want them to. This also avoids using the global namespace, which has a | |
| 1564 risc of name collisions. For example when you have two plugins with similar | |
| 1565 functionality. | |
|
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1566 |
| 27162 | 1567 You can cheat by using the global namespace explicitly. That should be done |
| 1568 only for things that really are global. | |
| 21991 | 1569 |
|
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1570 |
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1571 Namespace ~ |
|
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1572 *vim9-namespace* |
| 19303 | 1573 To recognize a file that can be imported the `vim9script` statement must |
|
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1574 appear as the first statement in the file (see |vim9-mix| for an exception). |
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1575 It tells Vim to interpret the script in its own namespace, instead of the |
|
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1576 global namespace. If a file starts with: > |
|
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1577 vim9script |
|
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1578 var myvar = 'yes' |
|
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1579 Then "myvar" will only exist in this file. While without `vim9script` it would |
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1580 be available as `g:myvar` from any other script and function. |
| 27459 | 1581 *E1101* |
|
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1582 The variables at the file level are very much like the script-local "s:" |
| 20115 | 1583 variables in legacy Vim script, but the "s:" is omitted. And they cannot be |
| 1584 deleted. | |
|
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1585 |
| 20115 | 1586 In Vim9 script the global "g:" namespace can still be used as before. And the |
| 1587 "w:", "b:" and "t:" namespaces. These have in common that variables are not | |
| 1588 declared and they can be deleted. | |
|
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1589 |
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1590 A side effect of `:vim9script` is that the 'cpoptions' option is set to the |
|
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1591 Vim default value, like with: > |
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1592 :set cpo&vim |
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1593 One of the effects is that |line-continuation| is always enabled. |
|
24150
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1594 The original value of 'cpoptions' is restored at the end of the script, while |
|
4919f2d8d7fd
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1595 flags added or removed in the script are also added to or removed from the |
|
4919f2d8d7fd
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1596 original value to get the same effect. The order of flags may change. |
|
26745
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1597 In the |vimrc| file sourced on startup this does not happen. |
|
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1598 |
|
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1599 *vim9-mix* |
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1600 There is one way to use both legacy and Vim9 syntax in one script file: > |
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1601 " comments may go here |
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1602 if !has('vim9script') |
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1603 " legacy script commands go here |
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1604 finish |
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1605 endif |
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1606 vim9script |
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1607 # Vim9 script commands go here |
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|
1608 This allows for writing a script that takes advantage of the Vim9 script |
| 24024 | 1609 syntax if possible, but will also work on a Vim version without it. |
|
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1610 |
|
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1611 This can only work in two ways: |
|
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|
1612 1. The "if" statement evaluates to false, the commands up to `endif` are |
|
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|
1613 skipped and `vim9script` is then the first command actually executed. |
|
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|
1614 2. The "if" statement evaluates to true, the commands up to `endif` are |
|
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|
1615 executed and `finish` bails out before reaching `vim9script`. |
|
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|
1616 |
|
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|
1617 |
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|
1618 Export ~ |
|
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|
1619 *:export* *:exp* |
| 21499 | 1620 Exporting an item can be written as: > |
|
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|
1621 export const EXPORTED_CONST = 1234 |
|
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patch 8.2.1744: Vim9: using ":const!" is weird
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|
1622 export var someValue = ... |
|
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|
1623 export final someValue = ... |
|
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|
1624 export const someValue = ... |
|
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|
1625 export def MyFunc() ... |
|
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|
1626 export class MyClass ... |
|
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|
1627 export interface MyClass ... |
| 27321 | 1628 < *E1043* *E1044* |
|
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|
1629 As this suggests, only constants, variables, `:def` functions and classes can |
|
24888
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|
1630 be exported. {not implemented yet: class, interface} |
|
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|
1631 |
| 20856 | 1632 *E1042* |
| 1633 `:export` can only be used in Vim9 script, at the script level. | |
|
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|
1634 |
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|
1635 |
|
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|
1636 Import ~ |
| 27537 | 1637 *:import* *:imp* *E1094* *E1047* *E1262* |
| 1638 *E1048* *E1049* *E1053* *E1071* *E1236* | |
|
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|
1639 The exported items can be imported in another Vim9 script: > |
|
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|
1640 import "myscript.vim" |
|
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1641 |
|
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|
1642 This makes each item available as "myscript.item". |
| 27537 | 1643 *:import-as* *E1257* *E1261* |
|
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|
1644 In case the name is long or ambiguous, another name can be specified: > |
| 27036 | 1645 import "thatscript.vim" as that |
| 27537 | 1646 < *E1060* *E1258* *E1259* *E1260* |
| 27036 | 1647 Then you can use "that.EXPORTED_CONST", "that.someValue", etc. You are free |
| 1648 to choose the name "that". Use something that will be recognized as referring | |
| 27459 | 1649 to the imported script. Avoid command names, command modifiers and builtin |
| 1650 function names, because the name will shadow them. | |
| 1651 If the name starts with a capital letter it can also shadow global user | |
| 1652 commands and functions. Also, you cannot use the name for something else in | |
| 1653 the script, such as a function or variable name. | |
|
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|
1654 |
| 27036 | 1655 In case the dot in the name is undesired, a local reference can be made for a |
| 1656 function: > | |
| 1657 var LongFunc = that.LongFuncName | |
|
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|
1658 |
|
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|
1659 This also works for constants: > |
| 27036 | 1660 const MAXLEN = that.MAX_LEN_OF_NAME |
|
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|
1661 |
| 27036 | 1662 This does not work for variables, since the value would be copied once and |
| 1663 when changing the variable the copy will change, not the original variable. | |
| 1664 You will need to use the full name, with the dot. | |
|
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|
1665 |
| 27321 | 1666 The full syntax of the command is: |
| 1667 import {filename} [as {name}] | |
| 1668 Where {filename} is an expression that must evaluate to a string. Without the | |
| 1669 "as {name}" part it must end in ".vim". {name} must consist of letters, | |
| 1670 digits and '_', like |internal-variables|. | |
| 1671 | |
| 22171 | 1672 `:import` can also be used in legacy Vim script. The imported items still |
| 1673 become script-local, even when the "s:" prefix is not given. | |
| 1674 | |
|
25282
9bce044c7643
patch 8.2.3178: Vim9: the file name of an :import cannot be an expression
Bram Moolenaar <Bram@vim.org>
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|
1675 `:import` can not be used in a function. Imported items are intended to exist |
|
9bce044c7643
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|
1676 at the script level and only imported once. |
|
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|
1677 |
|
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|
1678 The script name after `import` can be: |
|
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|
1679 - A relative path, starting "." or "..". This finds a file relative to the |
|
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|
1680 location of the script file itself. This is useful to split up a large |
|
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|
1681 plugin into several files. |
|
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|
1682 - An absolute path, starting with "/" on Unix or "D:/" on MS-Windows. This |
| 22723 | 1683 will rarely be used. |
|
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1684 - A path not being relative or absolute. This will be found in the |
|
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|
1685 "import" subdirectories of 'runtimepath' entries. The name will usually be |
|
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|
1686 longer and unique, to avoid loading the wrong file. |
| 25619 | 1687 Note that "after/import" is not used. |
|
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|
1688 |
| 27036 | 1689 If the name does not end in ".vim" then the use of "as name" is required. |
| 1690 | |
|
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|
1691 Once a vim9 script file has been imported, the result is cached and used the |
|
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|
1692 next time the same script is imported. It will not be read again. |
|
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|
1693 |
|
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|
1694 It is not allowed to import the same script twice, also when using two |
|
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|
1695 different "as" names. |
| 27036 | 1696 |
| 1697 When using the imported name the dot and the item name must be in the same | |
| 1698 line, there can be no line break: > | |
| 1699 echo that. | |
| 1700 name # Error! | |
| 1701 echo that | |
| 1702 .name # Error! | |
| 1703 < *:import-cycle* | |
| 27537 | 1704 The `import` commands are executed when encountered. If script A imports |
| 1705 script B, and B (directly or indirectly) imports A, this will be skipped over. | |
| 1706 At this point items in A after "import B" will not have been processed and | |
| 1707 defined yet. Therefore cyclic imports can exist and not result in an error | |
| 1708 directly, but may result in an error for items in A after "import B" not being | |
| 1709 defined. This does not apply to autoload imports, see the next section. | |
|
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|
1710 |
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|
1711 |
| 27162 | 1712 Importing an autoload script ~ |
|
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|
1713 *vim9-autoload* |
|
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|
1714 For optimal startup speed, loading scripts should be postponed until they are |
|
27043
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patch 8.2.4050: Vim9: need to prefix every item in an autoload script
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|
1715 actually needed. Using the autoload mechanism is recommended: |
| 27537 | 1716 *E1264* |
|
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|
1717 1. In the plugin define user commands, functions and/or mappings that refer to |
|
27043
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|
1718 items imported from an autoload script. > |
|
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|
1719 import autoload 'for/search.vim' |
|
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|
1720 command -nargs=1 SearchForStuff search.Stuff(<f-args>) |
|
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1721 |
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|
1722 < This goes in .../plugin/anyname.vim. "anyname.vim" can be freely chosen. |
|
27043
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|
1723 The "SearchForStuff" command is now available to the user. |
|
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|
1724 |
|
27043
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|
1725 The "autoload" argument to `:import` means that the script is not loaded |
|
15f40772e10a
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|
1726 until one of the items is actually used. The script will be found under |
|
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|
1727 the "autoload" directory in 'runtimepath' instead of the "import" |
|
15f40772e10a
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|
1728 directory. |
|
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|
1729 |
|
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|
1730 2. In the autoload script put the bulk of the code. > |
|
27215
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|
1731 vim9script |
|
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|
1732 export def Stuff(arg: string) |
|
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1733 ... |
|
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1734 |
|
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|
1735 < This goes in .../autoload/for/search.vim. |
|
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1736 |
|
27215
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|
1737 Putting the "search.vim" script under the "/autoload/for/" directory has |
|
5b54f413d132
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|
1738 the effect that "for#search#" will be prefixed to every exported item. The |
|
5b54f413d132
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|
1739 prefix is obtained from the file name, as you would to manually in a |
|
5b54f413d132
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|
1740 legacy autoload script. Thus the exported function can be found with |
|
5b54f413d132
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|
1741 "for#search#Stuff", but you would normally use `import autoload` and not |
|
5b54f413d132
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|
1742 use the prefix. |
|
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1743 |
|
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|
1744 You can split up the functionality and import other scripts from the |
|
15f40772e10a
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|
1745 autoload script as you like. This way you can share code between plugins. |
|
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1746 |
| 27162 | 1747 For defining a mapping that uses the imported autoload script the special key |
| 1748 |<ScriptCmd>| is useful. It allows for a command in a mapping to use the | |
| 1749 script context of where the mapping was defined. | |
| 1750 | |
|
21771
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patch 8.2.1435: Vim9: always converting to string for ".." leads to mistakes
Bram Moolenaar <Bram@vim.org>
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|
1751 When compiling a `:def` function and a function in an autoload script is |
|
fcf978444298
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Bram Moolenaar <Bram@vim.org>
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|
1752 encountered, the script is not loaded until the `:def` function is called. |
|
27043
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1753 This also means you get any errors only at runtime, since the argument and |
|
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1754 return types are not known yet. |
|
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|
1755 |
| 27162 | 1756 For testing the |test_override()| function can be used to have the |
| 1757 `import autoload` load the script right away, so that the items and types can | |
| 1758 be checked without waiting for them to be actually used: > | |
| 1759 test_override('autoload', 1) | |
| 1760 Reset it later with: > | |
| 1761 test_override('autoload', 0) | |
| 1762 Or: > | |
| 1763 test_override('ALL', 0) | |
| 1764 | |
|
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1765 |
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1766 Import in legacy Vim script ~ |
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1767 |
| 20856 | 1768 If an `import` statement is used in legacy Vim script, the script-local "s:" |
| 27162 | 1769 namespace will be used for the imported items, even when "s:" is not |
| 1770 specified. | |
|
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1771 |
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1772 |
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1773 ============================================================================== |
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1774 |
| 22328 | 1775 6. Future work: classes *vim9-classes* |
| 1776 | |
| 1777 Above "class" was mentioned a few times, but it has not been implemented yet. | |
|
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1778 Most of Vim9 script can be created without this functionality, and since |
| 22328 | 1779 implementing classes is going to be a lot of work, it is left for the future. |
| 1780 For now we'll just make sure classes can be added later. | |
| 1781 | |
| 1782 Thoughts: | |
|
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1783 - `class` / `endclass`, the whole class must be in one file |
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1784 - Class names are always CamelCase (to avoid a name clash with builtin types) |
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1785 - A single constructor called "constructor" |
| 22328 | 1786 - Single inheritance with `class ThisClass extends BaseClass` |
|
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1787 - `abstract class` (class with incomplete implementation) |
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1788 - `interface` / `endinterface` (abstract class without any implementation) |
| 22328 | 1789 - `class SomeClass implements SomeInterface` |
| 1790 - Generics for class: `class <Tkey, Tentry>` | |
| 1791 - Generics for function: `def <Tkey> GetLast(key: Tkey)` | |
| 1792 | |
|
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1793 Again, much of this is from TypeScript with a slightly different syntax. |
| 22328 | 1794 |
| 1795 Some things that look like good additions: | |
| 1796 - Use a class as an interface (like Dart) | |
| 1797 - Extend a class with methods, using an import (like Dart) | |
|
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1798 - Mixins |
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1799 - For testing: Mock mechanism |
| 22328 | 1800 |
| 1801 An important class that will be provided is "Promise". Since Vim is single | |
| 1802 threaded, connecting asynchronous operations is a natural way of allowing | |
| 1803 plugins to do their work without blocking the user. It's a uniform way to | |
| 1804 invoke callbacks and handle timeouts and errors. | |
| 1805 | |
| 28010 | 1806 Some commands have already been reserved: |
| 1807 *:class* | |
| 1808 *:endclass* | |
| 1809 *:abstract* | |
| 1810 *:enum* | |
| 1811 *:endenum* | |
| 1812 *:interface* | |
| 1813 *:endinterface* | |
| 1814 *:static* | |
| 1815 *:type* | |
| 1816 | |
|
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1817 Some examples: > |
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1818 |
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1819 abstract class Person |
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1820 static const prefix = 'xxx' |
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1821 var name: string |
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1822 |
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1823 def constructor(name: string) |
| 25402 | 1824 this.name = name |
|
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1825 enddef |
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1826 |
|
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1827 def display(): void |
|
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1828 echo name |
|
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1829 enddef |
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1830 |
|
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1831 abstract def find(string): Person |
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1832 endclass |
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1833 |
| 22328 | 1834 ============================================================================== |
| 1835 | |
|
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1836 9. Rationale *vim9-rationale* |
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1837 |
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1838 The :def command ~ |
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1839 |
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1840 Plugin writers have asked for much faster Vim script. Investigations have |
| 19303 | 1841 shown that keeping the existing semantics of function calls make this close to |
|
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1842 impossible, because of the overhead involved with calling a function, setting |
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1843 up the local function scope and executing lines. There are many details that |
|
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1844 need to be handled, such as error messages and exceptions. The need to create |
|
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1845 a dictionary for a: and l: scopes, the a:000 list and several others add too |
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1846 much overhead that cannot be avoided. |
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1847 |
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1848 Therefore the `:def` method to define a new-style function had to be added, |
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1849 which allows for a function with different semantics. Most things still work |
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1850 as before, but some parts do not. A new way to define a function was |
|
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1851 considered the best way to separate the legacy style code from Vim9 style code. |
|
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1852 |
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1853 Using "def" to define a function comes from Python. Other languages use |
|
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1854 "function" which clashes with legacy Vim script. |
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1855 |
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1856 |
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1857 Type checking ~ |
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1858 |
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1859 When compiling lines of Vim commands into instructions as much as possible |
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1860 should be done at compile time. Postponing it to runtime makes the execution |
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1861 slower and means mistakes are found only later. For example, when |
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1862 encountering the "+" character and compiling this into a generic add |
| 23666 | 1863 instruction, at runtime the instruction would have to inspect the type of the |
| 1864 arguments and decide what kind of addition to do. And when the type is | |
| 1865 dictionary throw an error. If the types are known to be numbers then an "add | |
| 1866 number" instruction can be used, which is faster. The error can be given at | |
| 1867 compile time, no error handling is needed at runtime, since adding two numbers | |
| 1868 cannot fail. | |
|
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1869 |
|
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1870 The syntax for types, using <type> for compound types, is similar to Java. It |
|
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1871 is easy to understand and widely used. The type names are what were used in |
|
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1872 Vim before, with some additions such as "void" and "bool". |
|
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1873 |
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1874 |
| 22328 | 1875 Removing clutter and weirdness ~ |
| 20856 | 1876 |
| 22328 | 1877 Once decided that `:def` functions have different syntax than legacy functions, |
| 1878 we are free to add improvements to make the code more familiar for users who | |
| 1879 know popular programming languages. In other words: remove weird things that | |
|
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1880 only Vim does. |
| 22328 | 1881 |
| 1882 We can also remove clutter, mainly things that were done to make Vim script | |
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1883 backwards compatible with the good old Vi commands. |
| 20856 | 1884 |
| 22328 | 1885 Examples: |
| 1886 - Drop `:call` for calling a function and `:eval` for manipulating data. | |
| 1887 - Drop using a leading backslash for line continuation, automatically figure | |
| 1888 out where an expression ends. | |
| 20856 | 1889 |
| 22328 | 1890 However, this does require that some things need to change: |
| 1891 - Comments start with # instead of ", to avoid confusing them with strings. | |
|
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1892 This is good anyway, it is known from several popular languages. |
| 22328 | 1893 - Ex command ranges need to be prefixed with a colon, to avoid confusion with |
| 1894 expressions (single quote can be a string or a mark, "/" can be divide or a | |
| 1895 search command, etc.). | |
| 1896 | |
| 1897 Goal is to limit the differences. A good criteria is that when the old syntax | |
|
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1898 is accidentally used you are very likely to get an error message. |
| 20856 | 1899 |
| 1900 | |
|
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1901 Syntax and semantics from popular languages ~ |
|
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1902 |
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1903 Script writers have complained that the Vim script syntax is unexpectedly |
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1904 different from what they are used to. To reduce this complaint popular |
| 20856 | 1905 languages are used as an example. At the same time, we do not want to abandon |
| 1906 the well-known parts of legacy Vim script. | |
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1907 |
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1908 For many things TypeScript is followed. It's a recent language that is |
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1909 gaining popularity and has similarities with Vim script. It also has a |
| 22328 | 1910 mix of static typing (a variable always has a known value type) and dynamic |
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1911 typing (a variable can have different types, this changes at runtime). Since |
| 22328 | 1912 legacy Vim script is dynamically typed and a lot of existing functionality |
| 1913 (esp. builtin functions) depends on that, while static typing allows for much | |
| 1914 faster execution, we need to have this mix in Vim9 script. | |
| 1915 | |
| 22171 | 1916 There is no intention to completely match TypeScript syntax and semantics. We |
| 1917 just want to take those parts that we can use for Vim and we expect Vim users | |
| 22328 | 1918 will be happy with. TypeScript is a complex language with its own history, |
| 1919 advantages and disadvantages. To get an idea of the disadvantages read the | |
| 1920 book: "JavaScript: The Good Parts". Or find the article "TypeScript: the good | |
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1921 parts" and read the "Things to avoid" section. |
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1922 |
| 22328 | 1923 People familiar with other languages (Java, Python, etc.) will also find |
| 1924 things in TypeScript that they do not like or do not understand. We'll try to | |
| 1925 avoid those things. | |
|
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1926 |
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1927 Specific items from TypeScript we avoid: |
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1928 - Overloading "+", using it both for addition and string concatenation. This |
|
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1929 goes against legacy Vim script and often leads to mistakes. For that reason |
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1930 we will keep using ".." for string concatenation. Lua also uses ".." this |
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1931 way. And it allows for conversion to string for more values. |
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1932 - TypeScript can use an expression like "99 || 'yes'" in a condition, but |
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1933 cannot assign the value to a boolean. That is inconsistent and can be |
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1934 annoying. Vim recognizes an expression with && or || and allows using the |
|
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1935 result as a bool. The |falsy-operator| was added for the mechanism to use a |
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1936 default value. |
|
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1937 - TypeScript considers an empty string as Falsy, but an empty list or dict as |
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1938 Truthy. That is inconsistent. In Vim an empty list and dict are also |
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1939 Falsy. |
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1940 - TypeScript has various "Readonly" types, which have limited usefulness, |
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1941 since a type cast can remove the immutable nature. Vim locks the value, |
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1942 which is more flexible, but is only checked at runtime. |
| 27459 | 1943 - TypeScript has a complicated "import" statement that does not match how the |
| 1944 Vim import mechanism works. A much simpler mechanism is used instead, which | |
| 1945 matches that the imported script is only sourced once. | |
| 22171 | 1946 |
|
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1947 |
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1948 Declarations ~ |
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1949 |
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1950 Legacy Vim script uses `:let` for every assignment, while in Vim9 declarations |
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1951 are used. That is different, thus it's good to use a different command: |
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1952 `:var`. This is used in many languages. The semantics might be slightly |
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1953 different, but it's easily recognized as a declaration. |
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1954 |
| 23047 | 1955 Using `:const` for constants is common, but the semantics varies. Some |
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1956 languages only make the variable immutable, others also make the value |
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1957 immutable. Since "final" is well known from Java for only making the variable |
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1958 immutable we decided to use that. And then `:const` can be used for making |
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1959 both immutable. This was also used in legacy Vim script and the meaning is |
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1960 almost the same. |
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1961 |
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1962 What we end up with is very similar to Dart: > |
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1963 :var name # mutable variable and value |
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1964 :final name # immutable variable, mutable value |
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1965 :const name # immutable variable and value |
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1966 |
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1967 Since legacy and Vim9 script will be mixed and global variables will be |
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1968 shared, optional type checking is desirable. Also, type inference will avoid |
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1969 the need for specifying the type in many cases. The TypeScript syntax fits |
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1970 best for adding types to declarations: > |
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1971 var name: string # string type is specified |
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1972 ... |
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1973 name = 'John' |
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1974 const greeting = 'hello' # string type is inferred |
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1975 |
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1976 This is how we put types in a declaration: > |
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1977 var mylist: list<string> |
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1978 final mylist: list<string> = ['foo'] |
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1979 def Func(arg1: number, arg2: string): bool |
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1980 |
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1981 Two alternatives were considered: |
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1982 1. Put the type before the name, like Dart: > |
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1983 var list<string> mylist |
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1984 final list<string> mylist = ['foo'] |
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1985 def Func(number arg1, string arg2) bool |
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1986 2. Put the type after the variable name, but do not use a colon, like Go: > |
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1987 var mylist list<string> |
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1988 final mylist list<string> = ['foo'] |
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1989 def Func(arg1 number, arg2 string) bool |
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1990 |
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1991 The first is more familiar for anyone used to C or Java. The second one |
| 22565 | 1992 doesn't really have an advantage over the first, so let's discard the second. |
|
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1993 |
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1994 Since we use type inference the type can be left out when it can be inferred |
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1995 from the value. This means that after `var` we don't know if a type or a name |
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1996 follows. That makes parsing harder, not only for Vim but also for humans. |
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1997 Also, it will not be allowed to use a variable name that could be a type name, |
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1998 using `var string string` is too confusing. |
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1999 |
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2000 The chosen syntax, using a colon to separate the name from the type, adds |
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2001 punctuation, but it actually makes it easier to recognize the parts of a |
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2002 declaration. |
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2003 |
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2004 |
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2005 Expressions ~ |
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2006 |
| 22565 | 2007 Expression evaluation was already close to what other languages are doing. |
| 2008 Some details are unexpected and can be improved. For example a boolean | |
| 2009 condition would accept a string, convert it to a number and check if the | |
| 2010 number is non-zero. This is unexpected and often leads to mistakes, since | |
| 2011 text not starting with a number would be converted to zero, which is | |
| 22723 | 2012 considered false. Thus using a string for a condition would often not give an |
| 2013 error and be considered false. That is confusing. | |
|
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2014 |
| 23047 | 2015 In Vim9 type checking is stricter to avoid mistakes. Where a condition is |
| 22565 | 2016 used, e.g. with the `:if` command and the `||` operator, only boolean-like |
| 2017 values are accepted: | |
| 2018 true: `true`, `v:true`, `1`, `0 < 9` | |
| 2019 false: `false`, `v:false`, `0`, `0 > 9` | |
| 2020 Note that the number zero is false and the number one is true. This is more | |
| 22723 | 2021 permissive than most other languages. It was done because many builtin |
| 22565 | 2022 functions return these values. |
|
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2023 |
| 22565 | 2024 If you have any type of value and want to use it as a boolean, use the `!!` |
| 2025 operator: | |
| 24751 | 2026 true: `!!'text'`, `!![99]`, `!!{'x': 1}`, `!!99` |
| 22565 | 2027 false: `!!''`, `!![]`, `!!{}` |
| 2028 | |
| 2029 From a language like JavaScript we have this handy construct: > | |
| 2030 GetName() || 'unknown' | |
| 2031 However, this conflicts with only allowing a boolean for a condition. | |
| 2032 Therefore the "??" operator was added: > | |
| 2033 GetName() ?? 'unknown' | |
| 2034 Here you can explicitly express your intention to use the value as-is and not | |
| 2035 result in a boolean. This is called the |falsy-operator|. | |
|
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2036 |
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2037 |
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2038 Import and Export ~ |
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2039 |
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2040 A problem of legacy Vim script is that by default all functions and variables |
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2041 are global. It is possible to make them script-local, but then they are not |
| 22171 | 2042 available in other scripts. This defies the concept of a package that only |
| 2043 exports selected items and keeps the rest local. | |
|
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2044 |
| 21825 | 2045 In Vim9 script a mechanism very similar to the JavaScript import and export |
|
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2046 mechanism is supported. It is a variant to the existing `:source` command |
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2047 that works like one would expect: |
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2048 - Instead of making everything global by default, everything is script-local, |
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2049 unless exported. |
| 22171 | 2050 - When importing a script the symbols that are imported are explicitly listed, |
| 2051 avoiding name conflicts and failures if functionality is added later. | |
|
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2052 - The mechanism allows for writing a big, long script with a very clear API: |
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2053 the exported function(s) and class(es). |
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2054 - By using relative paths loading can be much faster for an import inside of a |
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2055 package, no need to search many directories. |
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2056 - Once an import has been used, it can be cached and loading it again can be |
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2057 avoided. |
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patch 8.2.0149: maintaining a Vim9 branch separately is more work
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2058 - The Vim-specific use of "s:" to make things script-local can be dropped. |
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patch 8.2.0149: maintaining a Vim9 branch separately is more work
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2059 |
| 20856 | 2060 When sourcing a Vim9 script from a legacy script, only the items defined |
| 2061 globally can be used, not the exported items. Alternatives considered: | |
| 2062 - All the exported items become available as script-local items. This makes | |
| 22171 | 2063 it uncontrollable what items get defined and likely soon leads to trouble. |
| 20856 | 2064 - Use the exported items and make them global. Disadvantage is that it's then |
| 2065 not possible to avoid name clashes in the global namespace. | |
| 2066 - Completely disallow sourcing a Vim9 script, require using `:import`. That | |
| 2067 makes it difficult to use scripts for testing, or sourcing them from the | |
| 2068 command line to try them out. | |
| 22171 | 2069 Note that you can also use `:import` in legacy Vim script, see above. |
| 20856 | 2070 |
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2071 |
| 22328 | 2072 Compiling functions early ~ |
| 2073 | |
| 2074 Functions are compiled when called or when `:defcompile` is used. Why not | |
| 2075 compile them early, so that syntax and type errors are reported early? | |
| 2076 | |
| 2077 The functions can't be compiled right away when encountered, because there may | |
| 2078 be forward references to functions defined later. Consider defining functions | |
| 2079 A, B and C, where A calls B, B calls C, and C calls A again. It's impossible | |
| 2080 to reorder the functions to avoid forward references. | |
| 2081 | |
| 2082 An alternative would be to first scan through the file to locate items and | |
| 2083 figure out their type, so that forward references are found, and only then | |
| 2084 execute the script and compile the functions. This means the script has to be | |
| 2085 parsed twice, which is slower, and some conditions at the script level, such | |
| 2086 as checking if a feature is supported, are hard to use. An attempt was made | |
| 2087 to see if it works, but it turned out to be impossible to make work nicely. | |
| 2088 | |
| 2089 It would be possible to compile all the functions at the end of the script. | |
| 2090 The drawback is that if a function never gets called, the overhead of | |
| 2091 compiling it counts anyway. Since startup speed is very important, in most | |
| 2092 cases it's better to do it later and accept that syntax and type errors are | |
| 2093 only reported then. In case these errors should be found early, e.g. when | |
| 2094 testing, the `:defcompile` command will help out. | |
| 2095 | |
| 2096 | |
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patch 8.2.1744: Vim9: using ":const!" is weird
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2097 Why not use an embedded language? ~ |
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2098 |
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2099 Vim supports interfaces to Perl, Python, Lua, Tcl and a few others. But |
| 22328 | 2100 these interfaces have never become widely used, for various reasons. When |
| 2101 Vim9 was designed a decision was made to make these interfaces lower priority | |
| 2102 and concentrate on Vim script. | |
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2103 |
| 22328 | 2104 Still, plugin writers may find other languages more familiar, want to use |
| 2105 existing libraries or see a performance benefit. We encourage plugin authors | |
| 2106 to write code in any language and run it as an external tool, using jobs and | |
| 2107 channels. We can try to make this easier somehow. | |
| 2108 | |
| 2109 Using an external tool also has disadvantages. An alternative is to convert | |
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2110 the tool into Vim script. For that to be possible without too much |
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2111 translation, and keeping the code fast at the same time, the constructs of the |
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2112 tool need to be supported. Since most languages support classes the lack of |
| 22171 | 2113 support for classes in Vim is then a problem. |
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2114 |
| 22328 | 2115 |
| 2116 Classes ~ | |
| 2117 | |
| 2118 Vim supports a kind-of object oriented programming by adding methods to a | |
| 2119 dictionary. With some care this can be made to work, but it does not look | |
| 2120 like real classes. On top of that, it's quite slow, because of the use of | |
| 2121 dictionaries. | |
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2122 |
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2123 The support of classes in Vim9 script is a "minimal common functionality" of |
| 22171 | 2124 class support in most languages. It works much like Java, which is the most |
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2125 popular programming language. |
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2126 |
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2127 |
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2128 |
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2129 vim:tw=78:ts=8:noet:ft=help:norl: |