Add Vim9Script support by sideshowbarker · Pull Request #205 · vim-jp/vim-vimlparser

sideshowbarker · 2026-02-12T12:55:32Z

Summary

Parse core Vim9Script constructs into proper AST nodes instead of routing them through parse_cmd_common, so downstream tools can analyze Vim9Script code without errors
Add # comment support when vim9script mode is active
Fix JS transpiler compile_let heuristic that incorrectly added var prefix to subscript assignments like named[pname] = 1

Motivation

Tools that depend on vim-vimlparser — such as vint and vim-language-server (which vendors the JS output directly) — report unexpected errors on valid Vim9Script code because the parser doesn't recognize constructs like def, typed parameters, or # comments. This adds structured parsing for the core Vim9Script syntax so these tools can handle Vim9Script files correctly.

Details

New node types: NODE_VIM9SCRIPT, NODE_DEF, NODE_ENDDEF, NODE_VAR, NODE_FINAL, NODE_EXPORT, NODE_IMPORT.
vim9script — sets a mode flag that enables # comments throughout the parser (in parse_one_cmd, parse_command, parse_comment, parse_trail, ends_excmds, separate_nextcmd).
def/enddef — parses typed parameters (name: type), default values (name: type = expr), variadic params (...name: type), and return type annotations (: returntype). Reads parameter names directly from the reader rather than using ExprTokenizer, since : is a valid name character in VimL identifiers and would cause x: to be tokenized as a single identifier.
var/final — parses variable declarations with optional type annotations. Same direct-reader approach to avoid the : tokenization issue.
export — wraps the inner command (def, var, etc.) by delegating to find_command + _parse_command, then moving the resulting nodes into the export node's body.
import — captures the import specification as a string.

Fixes #194

Parse core Vim9Script constructs into proper AST nodes so that downstream tools can analyze Vim9Script code without errors. New node types: NODE_VIM9SCRIPT, NODE_DEF, NODE_ENDDEF, NODE_VAR, NODE_FINAL, NODE_EXPORT, NODE_IMPORT. Parsers for vim9script, def/enddef (with typed parameters, return types, default values, variadics), var/final (with type annotations), export (wrapping inner commands), and import. The # comment syntax is supported when vim9script mode is active. Also fix JS transpiler heuristic for subscript assignments in compile_let to check for [ in addition to . when deciding whether to add var prefix. Fixes vim-jp#194

sideshowbarker · 2026-02-12T13:06:24Z

I started on this before seeing #204. The approach in that PR is clearly a much better solution than this. (I hadn’t even known yet about https://github.com/vim-jp/vim-vim9parser.) But I figured I’d go ahead and raise this anyway — in case it happens to be of any interest, or might be a possible interim solution until #204 gets merged.

@sideshowbarker

From a fork of vimlparser that adds basic support for vim9script See vim-jp/vim-vimlparser#205 And https://github.com/sideshowbarker/vim-vimlparser/tree/vim9script-support While not perfect, this is a great improvement, thanks @sideshowbarker A more comprehensive solution is under development, but not yet ready See vim-jp/vim-vimlparser#204 And https://github.com/vim-jp/vim-vim9parser

@sideshowbarker

From a fork of vimlparser that adds basic support for vim9script See vim-jp/vim-vimlparser#205 And https://github.com/sideshowbarker/vim-vimlparser/tree/vim9script-support While not perfect, this is a great improvement, thanks @sideshowbarker A more comprehensive solution is under development, but not yet ready See vim-jp/vim-vimlparser#204 And https://github.com/vim-jp/vim-vim9parser

jclsn · 2026-05-13T20:35:14Z

@ynkdir @mattn Can you please have a look at this? The vim9script support would be of a great help! There is a new language server written in it and it would be easier to develop, if there was proper LSP support!

mattn · 2026-05-14T01:58:03Z

+" VAR .ea .op .left .list .rest .right .type
+" FINAL .ea .op .left .list .rest .right .type


.type_str ?

mattn · 2026-05-14T01:58:13Z

 " HEREDOC .rlist .op .body
+" DEF .ea .body .left .rlist .default_args .attr .enddef
+" ENDDEF .ea
+" VAR .ea .op .left .list .rest .right .type


mattn · 2026-05-14T01:59:15Z

+        if self.reader.peekn(1) ==# ':'
+          call self.reader.getn(1)
+          call self.reader.skip_white()
+          call self.read_type()


return value unused

mattn · 2026-05-14T02:00:57Z

+      if self.reader.peekn(3) ==# '...'
+        call self.reader.getn(3)
+        call self.reader.skip_white()
+        let vname = self.reader.read_alpha()


vname should accept number letter or _

mattn · 2026-05-14T02:03:38Z

          \       || self.reader.getpos() !=# self.ea.argpos)
          \   && (self.ea.cmd.name !=# 'redir'
          \       || self.reader.getpos().i !=# self.ea.argpos.i + 1 || pc !=# '@'))
+          \ || (self.vim9script && c ==# '#' && self.ea.cmd.flags !~# '\<NOTRLCOM\>')


Vim 9 supports inline suffix comments, but it must place a space immediately before the comment character.

mattn · 2026-05-14T02:04:24Z

+  let node.str = ''
+  call self.reader.skip_white()
+  " Read the rest of the import line as a string (import autoload 'path' or import 'path' as Name)
+  let node.str = self.reader.getn(-1)


import './x.vim' as util # comment

comment strings are included.

mattn · 2026-05-14T02:06:08Z

+    let left = '(' . left . ')'
+  endif
+  let right = self.compile(a:node.right)
+  call self.out('(var %s %s %s)', a:node.op, left, right)


type name is lost. (type_str should have)

mattn · 2026-05-14T02:06:13Z

+    let left = '(' . left . ')'
+  endif
+  let right = self.compile(a:node.right)
+  call self.out('(final %s %s %s)', a:node.op, left, right)


type name is lost. (type_str should have)

mmrwoods mentioned this pull request Apr 13, 2026

Add support for vim9script, update docs for Vim 9.2 and Neovim 0.12 iamcco/vim-language-server#101

Open

jclsn mentioned this pull request May 13, 2026

vim9script, functions calls without :call iamcco/vim-language-server#78

Open

mattn reviewed May 14, 2026

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Add Vim9Script support#205

Add Vim9Script support#205
sideshowbarker wants to merge 1 commit into
vim-jp:masterfrom
sideshowbarker:vim9script-support

sideshowbarker commented Feb 12, 2026 •

edited

Loading

Uh oh!

sideshowbarker commented Feb 12, 2026

Uh oh!

jclsn commented May 13, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

mattn May 14, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

		" VAR .ea .op .left .list .rest .right .type
		" FINAL .ea .op .left .list .rest .right .type

Conversation

sideshowbarker commented Feb 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Motivation

Details

Uh oh!

sideshowbarker commented Feb 12, 2026

Uh oh!

jclsn commented May 13, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

sideshowbarker commented Feb 12, 2026 •

edited

Loading