@parser-generator/grammar-interpreter/lib/esm/__tests__/if/test.js

A Parser Generator that supports LL,SLR,LR1,LALR

import { EOF } from "@parser-generator/definition";
import { LRParser } from "@parser-generator/core";
import LTable from "./left";
import RTable from "./right";
/*

#GRAMMAR
S -> Stmt ;
Stmt -> If | Other <% (e)=>e[0] %> ;
If ->
    'if' Expr Stmt |
    'if' Expr Stmt 'else' Stmt
    <% (e)=> new IfStmt(e) %>;
Expr -> 'Expr' <% (e)=>e[0] %>;
Other -> 'Other' <% (e)=>e[0] %>;

#GRAMMAR
S -> Stmt ;
Stmt -> If | Other <% (e)=>e[0] %> ;
If ->
    'if' Expr Stmt |
    'if' Expr Stmt 'else' Stmt
    <% (e)=> new IfStmt(e) %>;
Expr -> 'Expr' <% (e)=>e[0] %>;
Other -> 'Other' <% (e)=>e[0] %>;

#SYMBOL_ASSOC_PREC
If left
*/
export class IfStmt {
    constructor(children) {
        this.children = children;
    }
    toString() {
        return "(" + this.children.join(" ") + ")";
    }
}
class Token {
    constructor(lexeme) {
        this.lexeme = lexeme;
    }
    key() {
        return this.lexeme;
    }
    toString() {
        return this.lexeme;
    }
}
class Lexer {
    constructor(lexemes) {
        this.i = 0;
        this.lexemes = lexemes;
    }
    peek() {
        return this.i >= this.lexemes.length ? new Token(EOF) : new Token(this.lexemes[this.i]);
    }
    next() {
        return this.i < this.lexemes.length ? new Token(this.lexemes[this.i++]) : new Token(EOF);
    }
}
export let parser1 = new LRParser(LTable);
let ast1 = parser1.parse(new Lexer(["if", "Expr", "if", "Expr", "Other", "else", "Other"]));
console.log(ast1.toString());
//(if Expr (if Expr Other) else Other)
export let parser2 = new LRParser(RTable);
let ast2 = parser2.parse(new Lexer(["if", "Expr", "if", "Expr", "Other", "else", "Other"]));
console.log(ast2.toString());
//(if Expr (if Expr Other else Other))
//# sourceMappingURL=test.js.map