chevrotain-allstar

import { Lexer, createToken, EmbeddedActionsParser } from 'chevrotain'; import { LLStarLookaheadStrategy } from 'chevrotain-allstar'; const A = createToken({ name: "A", pattern: /A/ }); const B = createToken({ name: "B", pattern: /B/ }); const C = createToken({ name: "C", pattern: /C/ }); const WhiteSpace = createToken({ name: "WhiteSpace", pattern: /\s+/, group: Lexer.SKIPPED }); const allTokens = [WhiteSpace, A, B, C]; class MyParser extends EmbeddedActionsParser { constructor() { super(allTokens, { lookaheadStrategy: new LLStarLookaheadStrategy() }); this.performSelfAnalysis(); } // Example production demonstrating a choice that might benefit from unbounded lookahead public statement = this.RULE('statement', () => { this.OR([ { ALT: () => { this.CONSUME(A); this.CONSUME(B); } }, { ALT: () => { this.CONSUME(A); this.CONSUME(C); } } ]); }); } const lexer = new Lexer(allTokens); const parser = new MyParser(); // Example usage with a simple input const inputText = "AC"; const lexingResult = lexer.tokenize(inputText); parser.input = lexingResult.tokens; const cst = parser.statement(); if (parser.errors.length > 0) { console.error("Parsing errors:\n" + parser.errors.map(err => err.message).join('\n')); } else { console.log("Parsing successful. CST:\n", JSON.stringify(cst, null, 2)); }