aboutsummaryrefslogtreecommitdiff
path: root/master/languages.html
blob: 15f89f6713799cbea8fe74fa523123d15cdd3534 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
<!DOCTYPE HTML>
<html lang="en" class="colibri" dir="ltr">
    <head>
        <!-- Book generated using mdBook -->
        <meta charset="UTF-8">
        <title>Languages</title>


        <!-- Custom HTML head -->
        
        <meta name="description" content="">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <meta name="theme-color" content="#ffffff">

        <link rel="icon" href="favicon.svg">
        <link rel="shortcut icon" href="favicon.png">
        <link rel="stylesheet" href="css/variables.css">
        <link rel="stylesheet" href="css/general.css">
        <link rel="stylesheet" href="css/chrome.css">
        <link rel="stylesheet" href="css/print.css" media="print">

        <!-- Fonts -->
        <link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
        <link rel="stylesheet" href="fonts/fonts.css">

        <!-- Highlight.js Stylesheets -->
        <link rel="stylesheet" href="highlight.css">
        <link rel="stylesheet" href="tomorrow-night.css">
        <link rel="stylesheet" href="ayu-highlight.css">

        <!-- Custom theme stylesheets -->
        <link rel="stylesheet" href="custom.css">

    </head>
    <body class="sidebar-visible no-js">
    <div id="body-container">
        <!-- Provide site root to javascript -->
        <script>
            var path_to_root = "";
            var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "colibri" : "colibri";
        </script>

        <!-- Work around some values being stored in localStorage wrapped in quotes -->
        <script>
            try {
                var theme = localStorage.getItem('mdbook-theme');
                var sidebar = localStorage.getItem('mdbook-sidebar');

                if (theme.startsWith('"') && theme.endsWith('"')) {
                    localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
                }

                if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
                    localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
                }
            } catch (e) { }
        </script>

        <!-- Set the theme before any content is loaded, prevents flash -->
        <script>
            var theme;
            try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
            if (theme === null || theme === undefined) { theme = default_theme; }
            var html = document.querySelector('html');
            html.classList.remove('colibri')
            html.classList.add(theme);
            var body = document.querySelector('body');
            body.classList.remove('no-js')
            body.classList.add('js');
        </script>

        <input type="checkbox" id="sidebar-toggle-anchor" class="hidden">

        <!-- Hide / unhide sidebar before it is displayed -->
        <script>
            var body = document.querySelector('body');
            var sidebar = null;
            var sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
            if (document.body.clientWidth >= 1080) {
                try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
                sidebar = sidebar || 'visible';
            } else {
                sidebar = 'hidden';
            }
            sidebar_toggle.checked = sidebar === 'visible';
            body.classList.remove('sidebar-visible');
            body.classList.add("sidebar-" + sidebar);
        </script>

        <nav id="sidebar" class="sidebar" aria-label="Table of contents">
            <div class="sidebar-scrollbox">
                <ol class="chapter"><li class="chapter-item expanded affix "><a href="title-page.html">Helix</a></li><li class="chapter-item expanded "><a href="install.html"><strong aria-hidden="true">1.</strong> Installation</a></li><li class="chapter-item expanded "><a href="usage.html"><strong aria-hidden="true">2.</strong> Usage</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="keymap.html"><strong aria-hidden="true">2.1.</strong> Keymap</a></li><li class="chapter-item expanded "><a href="commands.html"><strong aria-hidden="true">2.2.</strong> Commands</a></li><li class="chapter-item expanded "><a href="lang-support.html"><strong aria-hidden="true">2.3.</strong> Language support</a></li></ol></li><li class="chapter-item expanded "><a href="from-vim.html"><strong aria-hidden="true">3.</strong> Migrating from Vim</a></li><li class="chapter-item expanded "><a href="configuration.html"><strong aria-hidden="true">4.</strong> Configuration</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="themes.html"><strong aria-hidden="true">4.1.</strong> Themes</a></li><li class="chapter-item expanded "><a href="remapping.html"><strong aria-hidden="true">4.2.</strong> Key remapping</a></li><li class="chapter-item expanded "><a href="languages.html" class="active"><strong aria-hidden="true">4.3.</strong> Languages</a></li></ol></li><li class="chapter-item expanded "><a href="guides/index.html"><strong aria-hidden="true">5.</strong> Guides</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="guides/adding_languages.html"><strong aria-hidden="true">5.1.</strong> Adding languages</a></li><li class="chapter-item expanded "><a href="guides/textobject.html"><strong aria-hidden="true">5.2.</strong> Adding textobject queries</a></li><li class="chapter-item expanded "><a href="guides/indent.html"><strong aria-hidden="true">5.3.</strong> Adding indent queries</a></li><li class="chapter-item expanded "><a href="guides/injection.html"><strong aria-hidden="true">5.4.</strong> Adding injection queries</a></li><li class="chapter-item expanded "><a href="guides/rainbow_bracket_queries.html"><strong aria-hidden="true">5.5.</strong> Adding rainbow bracket queries</a></li></ol></li></ol>
            </div>
            <div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
        </nav>

        <!-- Track and set sidebar scroll position -->
        <script>
            var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox');
            sidebarScrollbox.addEventListener('click', function(e) {
                if (e.target.tagName === 'A') {
                    sessionStorage.setItem('sidebar-scroll', sidebarScrollbox.scrollTop);
                }
            }, { passive: true });
            var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll');
            sessionStorage.removeItem('sidebar-scroll');
            if (sidebarScrollTop) {
                // preserve sidebar scroll position when navigating via links within sidebar
                sidebarScrollbox.scrollTop = sidebarScrollTop;
            } else {
                // scroll sidebar to current active section when navigating via "next/previous chapter" buttons
                var activeSection = document.querySelector('#sidebar .active');
                if (activeSection) {
                    activeSection.scrollIntoView({ block: 'center' });
                }
            }
        </script>

        <div id="page-wrapper" class="page-wrapper">

            <div class="page">
                                <div id="menu-bar-hover-placeholder"></div>
                <div id="menu-bar" class="menu-bar sticky">
                    <div class="left-buttons">
                        <label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
                            <i class="fa fa-bars"></i>
                        </label>
                        <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
                            <i class="fa fa-paint-brush"></i>
                        </button>
                        <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
                            <li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="colibri">Colibri</button></li>
                        </ul>
                        <button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
                            <i class="fa fa-search"></i>
                        </button>
                    </div>

                    <h1 class="menu-title"></h1>

                    <div class="right-buttons">
                        <a href="print.html" title="Print this book" aria-label="Print this book">
                            <i id="print-button" class="fa fa-print"></i>
                        </a>
                        <a href="https://github.com/helix-editor/helix" title="Git repository" aria-label="Git repository">
                            <i id="git-repository-button" class="fa fa-github"></i>
                        </a>
                        <a href="https://github.com/helix-editor/helix/edit/master/book/src/languages.md" title="Suggest an edit" aria-label="Suggest an edit">
                            <i id="git-edit-button" class="fa fa-edit"></i>
                        </a>

                    </div>
                </div>

                <div id="search-wrapper" class="hidden">
                    <form id="searchbar-outer" class="searchbar-outer">
                        <input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
                    </form>
                    <div id="searchresults-outer" class="searchresults-outer hidden">
                        <div id="searchresults-header" class="searchresults-header"></div>
                        <ul id="searchresults">
                        </ul>
                    </div>
                </div>

                <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
                <script>
                    document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
                    document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
                    Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
                        link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
                    });
                </script>

                <div id="content" class="content">
                    <main>
                        <h1 id="languages"><a class="header" href="#languages">Languages</a></h1>
<p>Language-specific settings and settings for language servers are configured
in <code>languages.toml</code> files.</p>
<h2 id="languagestoml-files"><a class="header" href="#languagestoml-files"><code>languages.toml</code> files</a></h2>
<p>There are three possible locations for a <code>languages.toml</code> file:</p>
<ol>
<li>
<p>In the Helix source code, which lives in the
<a href="https://github.com/helix-editor/helix/blob/master/languages.toml">Helix repository</a>.
It provides the default configurations for languages and language servers.</p>
</li>
<li>
<p>In your <a href="./configuration.html">configuration directory</a>. This overrides values
from the built-in language configuration. For example, to disable
auto-LSP-formatting in Rust:</p>
<pre><code class="language-toml"># in &lt;config_dir&gt;/helix/languages.toml

[language-server.mylang-lsp]
command = "mylang-lsp"

[[language]]
name = "rust"
auto-format = false
</code></pre>
</li>
<li>
<p>In a <code>.helix</code> folder in your project. Language configuration may also be
overridden local to a project by creating a <code>languages.toml</code> file in a
<code>.helix</code> folder. Its settings will be merged with the language configuration
in the configuration directory and the built-in configuration.</p>
</li>
</ol>
<h2 id="language-configuration"><a class="header" href="#language-configuration">Language configuration</a></h2>
<p>Each language is configured by adding a <code>[[language]]</code> section to a
<code>languages.toml</code> file. For example:</p>
<pre><code class="language-toml">[[language]]
name = "mylang"
scope = "source.mylang"
injection-regex = "mylang"
file-types = ["mylang", "myl"]
comment-tokens = "#"
indent = { tab-width = 2, unit = "  " }
formatter = { command = "mylang-formatter" , args = ["--stdin"] }
language-servers = [ "mylang-lsp" ]
</code></pre>
<p>These configuration keys are available:</p>
<div class="table-wrapper"><table><thead><tr><th>Key</th><th>Description</th></tr></thead><tbody>
<tr><td><code>name</code></td><td>The name of the language</td></tr>
<tr><td><code>language-id</code></td><td>The language-id for language servers, checkout the table at <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocumentItem">TextDocumentItem</a> for the right id</td></tr>
<tr><td><code>scope</code></td><td>A string like <code>source.js</code> that identifies the language. Currently, we strive to match the scope names used by popular TextMate grammars and by the Linguist library. Usually <code>source.&lt;name&gt;</code> or <code>text.&lt;name&gt;</code> in case of markup languages</td></tr>
<tr><td><code>injection-regex</code></td><td>regex pattern that will be tested against a language name in order to determine whether this language should be used for a potential <a href="https://tree-sitter.github.io/tree-sitter/syntax-highlighting#language-injection">language injection</a> site.</td></tr>
<tr><td><code>file-types</code></td><td>The filetypes of the language, for example <code>["yml", "yaml"]</code>. See the file-type detection section below.</td></tr>
<tr><td><code>shebangs</code></td><td>The interpreters from the shebang line, for example <code>["sh", "bash"]</code></td></tr>
<tr><td><code>roots</code></td><td>A set of marker files to look for when trying to find the workspace root. For example <code>Cargo.lock</code>, <code>yarn.lock</code></td></tr>
<tr><td><code>auto-format</code></td><td>Whether to autoformat this language when saving</td></tr>
<tr><td><code>diagnostic-severity</code></td><td>Minimal severity of diagnostic for it to be displayed. (Allowed values: <code>Error</code>, <code>Warning</code>, <code>Info</code>, <code>Hint</code>)</td></tr>
<tr><td><code>comment-tokens</code></td><td>The tokens to use as a comment token, either a single token <code>"//"</code> or an array <code>["//", "///", "//!"]</code> (the first token will be used for commenting). Also configurable as <code>comment-token</code> for backwards compatibility</td></tr>
<tr><td><code>block-comment-tokens</code></td><td>The start and end tokens for a multiline comment either an array or single table of <code>{ start = "/*", end = "*/"}</code>. The first set of tokens will be used for commenting, any pairs in the array can be uncommented</td></tr>
<tr><td><code>indent</code></td><td>The indent to use. Has sub keys <code>unit</code> (the text inserted into the document when indenting; usually set to N spaces or <code>"\t"</code> for tabs) and <code>tab-width</code> (the number of spaces rendered for a tab)</td></tr>
<tr><td><code>language-servers</code></td><td>The Language Servers used for this language. See below for more information in the section <a href="#configuring-language-servers-for-a-language">Configuring Language Servers for a language</a></td></tr>
<tr><td><code>grammar</code></td><td>The tree-sitter grammar to use (defaults to the value of <code>name</code>)</td></tr>
<tr><td><code>formatter</code></td><td>The formatter for the language, it will take precedence over the lsp when defined. The formatter must be able to take the original file as input from stdin and write the formatted file to stdout</td></tr>
<tr><td><code>soft-wrap</code></td><td><a href="./configuration.html#editorsoft-wrap-section">editor.softwrap</a></td></tr>
<tr><td><code>text-width</code></td><td>Maximum line length. Used for the <code>:reflow</code> command and soft-wrapping if <code>soft-wrap.wrap-at-text-width</code> is set, defaults to <code>editor.text-width</code></td></tr>
<tr><td><code>workspace-lsp-roots</code></td><td>Directories relative to the workspace root that are treated as LSP roots. Should only be set in <code>.helix/config.toml</code>. Overwrites the setting of the same name in <code>config.toml</code> if set.</td></tr>
<tr><td><code>persistent-diagnostic-sources</code></td><td>An array of LSP diagnostic sources assumed unchanged when the language server resends the same set of diagnostics. Helix can track the position for these diagnostics internally instead. Useful for diagnostics that are recomputed on save.</td></tr>
<tr><td><code>rulers</code></td><td>Overrides the <code>editor.rulers</code> config key for the language.</td></tr>
<tr><td><code>rainbow-brackets</code></td><td>Overrides the <code>editor.rainbow-brackets</code> config key for the language.</td></tr>
</tbody></table>
</div>
<h3 id="file-type-detection-and-the-file-types-key"><a class="header" href="#file-type-detection-and-the-file-types-key">File-type detection and the <code>file-types</code> key</a></h3>
<p>Helix determines which language configuration to use based on the <code>file-types</code> key
from the above section. <code>file-types</code> is a list of strings or tables, for
example:</p>
<pre><code class="language-toml">file-types = ["toml", { glob = "Makefile" }, { glob = ".git/config" }, { glob = ".github/workflows/*.yaml" } ]
</code></pre>
<p>When determining a language configuration to use, Helix searches the file-types
with the following priorities:</p>
<ol>
<li>Glob: values in <code>glob</code> tables are checked against the full path of the given
file. Globs are standard Unix-style path globs (e.g. the kind you use in Shell)
and can be used to match paths for a specific prefix, suffix, directory, etc.
In the above example, the <code>{ glob = "Makefile" }</code> config would match files
with the name <code>Makefile</code>, the <code>{ glob = ".git/config" }</code> config would match
<code>config</code> files in <code>.git</code> directories, and the <code>{ glob = ".github/workflows/*.yaml" }</code>
config would match any <code>yaml</code> files in <code>.github/workflow</code> directories. Note
that globs should always use the Unix path separator <code>/</code> even on Windows systems;
the matcher will automatically take the machine-specific separators into account.
If the glob isn't an absolute path or doesn't already start with a glob prefix,
<code>*/</code> will automatically be added to ensure it matches for any subdirectory.</li>
<li>Extension: if there are no glob matches, any <code>file-types</code> string that matches
the file extension of a given file wins. In the example above, the <code>"toml"</code>
config matches files like <code>Cargo.toml</code> or <code>languages.toml</code>.</li>
</ol>
<h2 id="language-server-configuration"><a class="header" href="#language-server-configuration">Language Server configuration</a></h2>
<p>Language servers are configured separately in the table <code>language-server</code> in the same file as the languages <code>languages.toml</code></p>
<p>For example:</p>
<pre><code class="language-toml">[language-server.mylang-lsp]
command = "mylang-lsp"
args = ["--stdio"]
config = { provideFormatter = true }
environment = { "ENV1" = "value1", "ENV2" = "value2" }

[language-server.efm-lsp-prettier]
command = "efm-langserver"

[language-server.efm-lsp-prettier.config]
documentFormatting = true
languages = { typescript = [ { formatCommand ="prettier --stdin-filepath ${INPUT}", formatStdin = true } ] }
</code></pre>
<p>These are the available options for a language server.</p>
<div class="table-wrapper"><table><thead><tr><th>Key</th><th>Description</th></tr></thead><tbody>
<tr><td><code>command</code></td><td>The name or path of the language server binary to execute. Binaries must be in <code>$PATH</code></td></tr>
<tr><td><code>args</code></td><td>A list of arguments to pass to the language server binary</td></tr>
<tr><td><code>config</code></td><td>LSP initialization options</td></tr>
<tr><td><code>timeout</code></td><td>The maximum time a request to the language server may take, in seconds. Defaults to <code>20</code></td></tr>
<tr><td><code>environment</code></td><td>Any environment variables that will be used when starting the language server <code>{ "KEY1" = "Value1", "KEY2" = "Value2" }</code></td></tr>
<tr><td><code>required-root-patterns</code></td><td>A list of <code>glob</code> patterns to look for in the working directory. The language server is started if at least one of them is found.</td></tr>
</tbody></table>
</div>
<p>A <code>format</code> sub-table within <code>config</code> can be used to pass extra formatting options to
<a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_formatting">Document Formatting Requests</a>.
For example, with typescript:</p>
<pre><code class="language-toml">[language-server.typescript-language-server]
# pass format options according to https://github.com/typescript-language-server/typescript-language-server#workspacedidchangeconfiguration omitting the "[language].format." prefix.
config = { format = { "semicolons" = "insert", "insertSpaceBeforeFunctionParenthesis" = true } }
</code></pre>
<h3 id="configuring-language-servers-for-a-language"><a class="header" href="#configuring-language-servers-for-a-language">Configuring Language Servers for a language</a></h3>
<p>The <code>language-servers</code> attribute in a language tells helix which language servers are used for this language.</p>
<p>They have to be defined in the <code>[language-server]</code> table as described in the previous section.</p>
<p>Different languages can use the same language server instance, e.g. <code>typescript-language-server</code> is used for javascript, jsx, tsx and typescript by default.</p>
<p>In case multiple language servers are specified in the <code>language-servers</code> attribute of a <code>language</code>,
it's often useful to only enable/disable certain language-server features for these language servers.</p>
<p>As an example, <code>efm-lsp-prettier</code> of the previous example is used only with a formatting command <code>prettier</code>,
so everything else should be handled by the <code>typescript-language-server</code> (which is configured by default).
The language configuration for typescript could look like this:</p>
<pre><code class="language-toml">[[language]]
name = "typescript"
language-servers = [ { name = "efm-lsp-prettier", only-features = [ "format" ] }, "typescript-language-server" ]
</code></pre>
<p>or equivalent:</p>
<pre><code class="language-toml">[[language]]
name = "typescript"
language-servers = [ { name = "typescript-language-server", except-features = [ "format" ] }, "efm-lsp-prettier" ]
</code></pre>
<p>Each requested LSP feature is prioritized in the order of the <code>language-servers</code> array.
For example, the first <code>goto-definition</code> supported language server (in this case <code>typescript-language-server</code>) will be taken for the relevant LSP request (command <code>goto_definition</code>).
The features <code>diagnostics</code>, <code>code-action</code>, <code>completion</code>, <code>document-symbols</code> and <code>workspace-symbols</code> are an exception to that rule, as they are working for all language servers at the same time and are merged together, if enabled for the language.
If no <code>except-features</code> or <code>only-features</code> is given, all features for the language server are enabled.
If a language server itself doesn't support a feature, the next language server array entry will be tried (and so on).</p>
<p>The list of supported features is:</p>
<ul>
<li><code>format</code></li>
<li><code>goto-definition</code></li>
<li><code>goto-declaration</code></li>
<li><code>goto-type-definition</code></li>
<li><code>goto-reference</code></li>
<li><code>goto-implementation</code></li>
<li><code>signature-help</code></li>
<li><code>hover</code></li>
<li><code>document-highlight</code></li>
<li><code>completion</code></li>
<li><code>code-action</code></li>
<li><code>workspace-command</code></li>
<li><code>document-symbols</code></li>
<li><code>workspace-symbols</code></li>
<li><code>diagnostics</code></li>
<li><code>rename-symbol</code></li>
<li><code>inlay-hints</code></li>
</ul>
<h2 id="tree-sitter-grammar-configuration"><a class="header" href="#tree-sitter-grammar-configuration">Tree-sitter grammar configuration</a></h2>
<p>The source for a language's tree-sitter grammar is specified in a <code>[[grammar]]</code>
section in <code>languages.toml</code>. For example:</p>
<pre><code class="language-toml">[[grammar]]
name = "mylang"
source = { git = "https://github.com/example/mylang", rev = "a250c4582510ff34767ec3b7dcdd3c24e8c8aa68" }
</code></pre>
<p>Grammar configuration takes these keys:</p>
<div class="table-wrapper"><table><thead><tr><th>Key</th><th>Description</th></tr></thead><tbody>
<tr><td><code>name</code></td><td>The name of the tree-sitter grammar</td></tr>
<tr><td><code>source</code></td><td>The method of fetching the grammar - a table with a schema defined below</td></tr>
</tbody></table>
</div>
<p>Where <code>source</code> is a table with either these keys when using a grammar from a
git repository:</p>
<div class="table-wrapper"><table><thead><tr><th>Key</th><th>Description</th></tr></thead><tbody>
<tr><td><code>git</code></td><td>A git remote URL from which the grammar should be cloned</td></tr>
<tr><td><code>rev</code></td><td>The revision (commit hash or tag) which should be fetched</td></tr>
<tr><td><code>subpath</code></td><td>A path within the grammar directory which should be built. Some grammar repositories host multiple grammars (for example <code>tree-sitter-typescript</code> and <code>tree-sitter-ocaml</code>) in subdirectories. This key is used to point <code>hx --grammar build</code> to the correct path for compilation. When omitted, the root of repository is used</td></tr>
</tbody></table>
</div>
<h3 id="choosing-grammars"><a class="header" href="#choosing-grammars">Choosing grammars</a></h3>
<p>You may use a top-level <code>use-grammars</code> key to control which grammars are
fetched and built when using <code>hx --grammar fetch</code> and <code>hx --grammar build</code>.</p>
<pre><code class="language-toml"># Note: this key must come **before** the [[language]] and [[grammar]] sections
use-grammars = { only = [ "rust", "c", "cpp" ] }
# or
use-grammars = { except = [ "yaml", "json" ] }
</code></pre>
<p>When omitted, all grammars are fetched and built.</p>

                    </main>

                    <nav class="nav-wrapper" aria-label="Page navigation">
                        <!-- Mobile navigation buttons -->
                            <a rel="prev" href="remapping.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
                                <i class="fa fa-angle-left"></i>
                            </a>

                            <a rel="next prefetch" href="guides/index.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
                                <i class="fa fa-angle-right"></i>
                            </a>

                        <div style="clear: both"></div>
                    </nav>
                </div>
            </div>

            <nav class="nav-wide-wrapper" aria-label="Page navigation">
                    <a rel="prev" href="remapping.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
                        <i class="fa fa-angle-left"></i>
                    </a>

                    <a rel="next prefetch" href="guides/index.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
                        <i class="fa fa-angle-right"></i>
                    </a>
            </nav>

        </div>




        <script>
            window.playground_copyable = true;
        </script>


        <script src="elasticlunr.min.js"></script>
        <script src="mark.min.js"></script>
        <script src="searcher.js"></script>

        <script src="clipboard.min.js"></script>
        <script src="highlight.js"></script>
        <script src="book.js"></script>

        <!-- Custom JS scripts -->


    </div>
    </body>
</html>