Languages
+Language-specific settings and settings for language servers are configured
+in languages.toml
files.
languages.toml
files
+There are three possible locations for a languages.toml
file:
-
+
-
+
In the Helix source code, which lives in the +Helix repository. +It provides the default configurations for languages and language servers.
+
+ -
+
In your configuration directory. This overrides values +from the built-in language configuration. For example, to disable +auto-LSP-formatting in Rust:
+
+# in <config_dir>/helix/languages.toml + +[language-server.mylang-lsp] +command = "mylang-lsp" + +[[language]] +name = "rust" +auto-format = false +
+ -
+
In a
+.helix
folder in your project. Language configuration may also be +overridden local to a project by creating alanguages.toml
file in a +.helix
folder. Its settings will be merged with the language configuration +in the configuration directory and the built-in configuration.
+
Language configuration
+Each language is configured by adding a [[language]]
section to a
+languages.toml
file. For example:
[[language]]
+name = "mylang"
+scope = "source.mylang"
+injection-regex = "mylang"
+file-types = ["mylang", "myl"]
+comment-token = "#"
+indent = { tab-width = 2, unit = " " }
+formatter = { command = "mylang-formatter" , args = ["--stdin"] }
+language-servers = [ "mylang-lsp" ]
+
+These configuration keys are available:
+Key | Description |
---|---|
name | The name of the language |
language-id | The language-id for language servers, checkout the table at TextDocumentItem for the right id |
scope | A string like source.js that identifies the language. Currently, we strive to match the scope names used by popular TextMate grammars and by the Linguist library. Usually source.<name> or text.<name> in case of markup languages |
injection-regex | regex pattern that will be tested against a language name in order to determine whether this language should be used for a potential language injection site. |
file-types | The filetypes of the language, for example ["yml", "yaml"] . See the file-type detection section below. |
shebangs | The interpreters from the shebang line, for example ["sh", "bash"] |
roots | A set of marker files to look for when trying to find the workspace root. For example Cargo.lock , yarn.lock |
auto-format | Whether to autoformat this language when saving |
diagnostic-severity | Minimal severity of diagnostic for it to be displayed. (Allowed values: Error , Warning , Info , Hint ) |
comment-token | The token to use as a comment-token |
indent | The indent to use. Has sub keys unit (the text inserted into the document when indenting; usually set to N spaces or "\t" for tabs) and tab-width (the number of spaces rendered for a tab) |
language-servers | The Language Servers used for this language. See below for more information in the section Configuring Language Servers for a language |
grammar | The tree-sitter grammar to use (defaults to the value of name ) |
formatter | 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 |
text-width | Maximum line length. Used for the :reflow command and soft-wrapping if soft-wrap.wrap-at-text-width is set, defaults to editor.text-width |
workspace-lsp-roots | Directories relative to the workspace root that are treated as LSP roots. Should only be set in .helix/config.toml . Overwrites the setting of the same name in config.toml if set. |
rulers | Overrides the editor.rulers config key for the language. |
rainbow-brackets | Overrides the editor.rainbow-brackets config key for the language. |
File-type detection and the file-types
key
+Helix determines which language configuration to use based on the file-types
key
+from the above section. file-types
is a list of strings or tables, for
+example:
file-types = ["Makefile", "toml", { suffix = ".git/config" }]
+
+When determining a language configuration to use, Helix searches the file-types +with the following priorities:
+-
+
- Exact match: if the filename of a file is an exact match of a string in a
+
file-types
list, that language wins. In the example above,"Makefile"
+will match againstMakefile
files.
+ - Extension: if there are no exact matches, any
file-types
string that +matches the file extension of a given file wins. In the example above, the +"toml"
matches files likeCargo.toml
orlanguages.toml
.
+ - Suffix: if there are still no matches, any values in
suffix
tables +are checked against the full path of the given file. In the example above, +the{ suffix = ".git/config" }
would match against anyconfig
files +in.git
directories. Note:/
is used as the directory separator but is +replaced at runtime with the appropriate path separator for the operating +system, so this rule would match against.git\config
files on Windows.
+
Language Server configuration
+Language servers are configured separately in the table language-server
in the same file as the languages languages.toml
For example:
+[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 } ] }
+
+These are the available options for a language server.
+Key | Description |
---|---|
command | The name or path of the language server binary to execute. Binaries must be in $PATH |
args | A list of arguments to pass to the language server binary |
config | LSP initialization options |
timeout | The maximum time a request to the language server may take, in seconds. Defaults to 20 |
environment | Any environment variables that will be used when starting the language server { "KEY1" = "Value1", "KEY2" = "Value2" } |
A format
sub-table within config
can be used to pass extra formatting options to
+Document Formatting Requests.
+For example, with typescript:
[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 } }
+
+Configuring Language Servers for a language
+The language-servers
attribute in a language tells helix which language servers are used for this language.
They have to be defined in the [language-server]
table as described in the previous section.
Different languages can use the same language server instance, e.g. typescript-language-server
is used for javascript, jsx, tsx and typescript by default.
In case multiple language servers are specified in the language-servers
attribute of a language
,
+it's often useful to only enable/disable certain language-server features for these language servers.
As an example, efm-lsp-prettier
of the previous example is used only with a formatting command prettier
,
+so everything else should be handled by the typescript-language-server
(which is configured by default).
+The language configuration for typescript could look like this:
[[language]]
+name = "typescript"
+language-servers = [ { name = "efm-lsp-prettier", only-features = [ "format" ] }, "typescript-language-server" ]
+
+or equivalent:
+[[language]]
+name = "typescript"
+language-servers = [ { name = "typescript-language-server", except-features = [ "format" ] }, "efm-lsp-prettier" ]
+
+Each requested LSP feature is prioritized in the order of the language-servers
array.
+For example, the first goto-definition
supported language server (in this case typescript-language-server
) will be taken for the relevant LSP request (command goto_definition
).
+The features diagnostics
, code-action
, completion
, document-symbols
and workspace-symbols
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 except-features
or only-features
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).
The list of supported features is:
+-
+
format
+goto-definition
+goto-declaration
+goto-type-definition
+goto-reference
+goto-implementation
+signature-help
+hover
+document-highlight
+completion
+code-action
+workspace-command
+document-symbols
+workspace-symbols
+diagnostics
+rename-symbol
+inlay-hints
+
Tree-sitter grammar configuration
+The source for a language's tree-sitter grammar is specified in a [[grammar]]
+section in languages.toml
. For example:
[[grammar]]
+name = "mylang"
+source = { git = "https://github.com/example/mylang", rev = "a250c4582510ff34767ec3b7dcdd3c24e8c8aa68" }
+
+Grammar configuration takes these keys:
+Key | Description |
---|---|
name | The name of the tree-sitter grammar |
source | The method of fetching the grammar - a table with a schema defined below |
Where source
is a table with either these keys when using a grammar from a
+git repository:
Key | Description |
---|---|
git | A git remote URL from which the grammar should be cloned |
rev | The revision (commit hash or tag) which should be fetched |
subpath | A path within the grammar directory which should be built. Some grammar repositories host multiple grammars (for example tree-sitter-typescript and tree-sitter-ocaml ) in subdirectories. This key is used to point hx --grammar build to the correct path for compilation. When omitted, the root of repository is used |
Choosing grammars
+You may use a top-level use-grammars
key to control which grammars are
+fetched and built when using hx --grammar fetch
and hx --grammar build
.
# Note: this key must come **before** the [[language]] and [[grammar]] sections
+use-grammars = { only = [ "rust", "c", "cpp" ] }
+# or
+use-grammars = { except = [ "yaml", "json" ] }
+
+When omitted, all grammars are fetched and built.
+ +