Trait Language

pub trait Language: Clone {
    // Required method
    fn get_ts_language(&self) -> TSLanguage;

    // Provided methods
    fn from_path<P: AsRef<Path>>(_path: P) -> Option<Self> { ... }
    fn ast_grep<S: AsRef<str>>(&self, source: S) -> AstGrep<StrDoc<Self>> { ... }
    fn skippable_kind_ids(&self) -> &'static [u16] { ... }
    fn pre_process_pattern<'q>(&self, query: &'q str) -> Cow<'q, str> { ... }
    fn meta_var_char(&self) -> char { ... }
    fn expando_char(&self) -> char { ... }
    fn extract_meta_var(&self, source: &str) -> Option<MetaVariable> { ... }
    fn injectable_languages(&self) -> Option<&'static [&'static str]> { ... }
    fn extract_injections<D: Doc>(
        &self,
        _root: Node<'_, D>,
    ) -> HashMap<String, Vec<TSRange>> { ... }
}

Trait to abstract ts-language usage in ast-grep, which includes:

• which character is used for meta variable.
• if we need to use other char in meta var for parser at runtime
• pre process the Pattern code.

Required Methods

fn get_ts_language(&self) -> TSLanguage

tree sitter language to parse the source

Provided Methods

fn from_path<P: AsRef<Path>>(_path: P) -> Option<Self>

Return the file language from path. Return None if the file type is not supported.

fn ast_grep<S: AsRef<str>>(&self, source: S) -> AstGrep<StrDoc<Self>>

Create an AstGrep instance for the language

fn skippable_kind_ids(&self) -> &'static [u16]

ignore trivial tokens in language matching

fn pre_process_pattern<'q>(&self, query: &'q str) -> Cow<'q, str>

normalize pattern code before matching e.g. remove expression_statement, or prefer parsing {} to object over block

fn meta_var_char(&self) -> char

Configure meta variable special character By default $ is the metavar char, but in PHP it can be #

fn expando_char(&self) -> char

Some language does not accept $ as the leading char for identifiers. We need to change $ to other char at run-time to make parser happy, thus the name expando. By default this is the same as meta_var char so replacement is done at runtime.

fn extract_meta_var(&self, source: &str) -> Option<MetaVariable>

extract MetaVariable from a given source string At runtime we need to use expand_char

fn injectable_languages(&self) -> Option<&'static [&'static str]>

fn extract_injections<D: Doc>( &self, _root: Node<'_, D>, ) -> HashMap<String, Vec<TSRange>>

get injected language regions in the root document. e.g. get JavaScripts in HTML it will return a list of tuples of (language, regions). The first item is the embedded region language, e.g. javascript The second item is a list of regions in tree_sitter. also see https://tree-sitter.github.io/tree-sitter/using-parsers#multi-language-documents

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Language for TSLanguage