How to add support for a language

The following guides detail the steps necessary to add or upgrade support for a particular programming language.

Symbols support

To support symbol search and the symbols sidebar:

  1. Add or update the target language’s configuration in sourcegraph/go-ctags/.ctags.d. The universal-ctags/ctags project bundles configuration for many languages, but additional or override configuration may be necessary to support missing or correct incorrectly parsed language features. Examples:
    • scala (new language)
    • clojure (additional patterns)
    • css (additional file extensions)
  2. Update the sourcegraph/go-ctags dependency in sourcegraph/zoekt.
  3. Update the sourcegraph/go-ctags dependency in sourcegraph/sourcegraph.
  4. Run ./dev/zoekt/update in sourcegraph/sourcegraph to pull in the new zoekt version.

Development

You can validate your changes to the .ctag.d definitions by observing the symbol search and symbol sidebar behaviors in a local Sourcegraph. Link your Sourcegraph instance and your local clone of go-ctags by adding the following to the go.mod file in sourcegraph/sourcegraph.

replace github.com/sourcegraph/go-ctags => /path/to/my/clone/of/sourcegraph/go-ctags

Remember to run the code-generation step in the go-ctags repository and restart your local instance after each change to a definition file.

Note: Because we have not yet updated Zoekt, you will need to ensure that your symbol search and symbol sidebar operations are not on an indexed branch. These paths must hit the unindexed symbols paths in order to hit the code path with updated ctags definitions.

Code intelligence support

To support precise code intelligence, write an SCIP indexer. To support search-based code intelligence, ensure a sourcegraph/{lang} Sourcegraph extension is published to the official extension registry:

  1. Code intelligence extensions are powered by symbol search. If the target language is not supported by symbols, stop and follow the guide above first.
  2. Add (or update) the target language’s configuration in languages.ts. See the definition of LanguageSpec for an available set of fields. The likely differences will be the characters that make up the identifier, the comment delimiters, and the set of file extensions to search within for definitions and references.
  3. Ensure an icon exists for the target language. This ensures that the BuildKite pipeline will generate and publish an extension for the new language definition.
  4. Correlate the language’s file extensions and the new Sourcegraph extension by adding entries to the switch in getModeFromExtension. This enables the providers from the Sourcegraph extension to be registered when a text document with the correlated extensions is opened. The value returned from this function and the languageId from the language’s configuration should match exactly.

Syntax highlighting support

Customizing Syntax Highlight Language

The following settings apply only to the site settings. They are global configuration options for your Sourcegraph instance.

If you have a custom language that is derived from an existing language, it is possible to configure Sourcegraph to highlight that language as another.

For example:

{
  "syntaxHighlighting": {
   "languages": {
     "extensions": {
        "strato": "scala"
      },
      "patterns": []
    }
  }
}

If you have custom file extensions that map to an existing language, it is possible to configure Sourcegraph to highlight those files as an existing language.

For example:

{
  "syntaxHighlighting": {
   "languages": {
     "extensions": {
        "module": "php",
        "inc": "php"
      },
      "patterns": []
    }
  }
}

NOTE: In both cases, the . is dropped from the file extension.

Additionally, for more complex matching, it possible to pass regexes that will be evaluated (in order listed in the configuration) and if a match is found, will override the syntax highlight language for that file.

For example:

{
  "syntaxHighlighting": {
    "languages": {
      "extensions": {},
      "patterns": [
        {
          "language": "bash",
          "pattern": "bash.rc"
        },
        {
          "language": "bash",
          "pattern": ".bashprofile"
        }
      ]
    }
  }
}

Adding New Syntax Highlighting

To support syntax highlighting on code files, search results, diff views, and more:

  1. Follow the directions to add a language to syntect server.
  2. Update the SyntectLanguageMap in sourcegraph/sourcegraph.

To support syntax highlighting in hovers:

  1. Update the highlight.js contributions map in sourcegraph/sourcegraph.

Search support

Coming soon.