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24d43849a0
* pref: optimize `common` rules and matchers * chore: rename diagrams services to short form * chore: sort imports
Mermaid Parser
Mermaid parser package
How the package works
The package exports a parse function that has two parameters:
declare function parse<T extends DiagramAST>(
diagramType: keyof typeof initializers,
text: string
): T;
How does a Langium-based parser work?
sequenceDiagram
actor Package
participant Module
participant TokenBuilder
participant Lexer
participant Parser
participant ValueConverter
Package ->> Module: Create services
Module ->> TokenBuilder: Override or/and<br>reorder rules
TokenBuilder ->> Lexer: Read the string and transform<br>it into a token stream
Lexer ->> Parser: Parse token<br>stream into AST
Parser ->> ValueConverter: Clean/modify tokenized<br>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.