Mermaid Parser

Mermaid parser package

[](https://www.npmjs.com/package/@mermaid-js/parser) ## How the package works The package exports a `parse` function that has two parameters: ```ts declare function parse( diagramType: keyof typeof initializers, text: string ): T; ``` ## How does a Langium-based parser work? ```mermaid sequenceDiagram actor Package participant Module participant TokenBuilder participant Lexer participant Parser participant ValueConverter Package ->> Module: Create services Module ->> TokenBuilder: Override or/and
reorder rules TokenBuilder ->> Lexer: Read the string and transform
it into a token stream Lexer ->> Parser: Parse token
stream into AST Parser ->> ValueConverter: Clean/modify tokenized
rules returned value ValueConverter -->> Package: Return AST ``` - When to override `TokenBuilder`? - To override keyword rules. - To override terminal rules that need a custom function. - To manually reorder the list of rules. - When to override `Lexer`? - To modify input before tokenizing. - To insert/modify tokens that cannot or have not been parsed. - When to override `LangiumParser`? - To insert or modify attributes that can't be parsed. - When to override `ValueConverter`? - To modify the returned value from the parser.