(function (factory) {
 if (typeof module === "object" && typeof module.exports === "object") {
 var v = factory(require, exports);
 if (v !== undefined) module.exports = v;
 }
 else if (typeof define === "function" && define.amd) {
 define(["require", "exports", "../tokenizer/tokenizer", "./statement", "./expression", "./terminal", "./exprParser"], factory);
 }
})(function (require, exports) {
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 const tokenizer_1 = require("../tokenizer/tokenizer");
 const statement_1 = require("./statement");
 const expression_1 = require("./expression");
 const terminal_1 = require("./terminal");
 const exprParser_1 = require("./exprParser");
 /**
 * 自顶部向下递归+lookahead一个token的parser
 * Program -> Stmts
 * Stmts -> Stmt Stmts | ε
 * Stmt -> AssignExpr | IfStmt | WhileStmt | Function | Block | ...
 * xxStmt -> Expr | Stmt | Terminal
 * Expr -> Terminal
 */
 class Parser {
 //语法分析函数
 parse(sourceCode) {
 //从词法分析器拿到tokens
 this.tokens = new tokenizer_1.Tokenizer(sourceCode).tokens;
 // 增加一个哨兵,用于判断结尾
 this.tokens.push({ type: 'eof', value: null });
 this.index = 0;
 this.lookahead = this.tokens[this.index++];
 const program = this.parseProgram();
 program.buildLexicalScope();
 return program;
 }
 //向前读一个token:封装index,避免危险操作
 read() {
 if (this.lookahead.type !== 'eof') {
 this.lookahead = this.tokens[this.index++];
 }
 }
 //校验token,并向前读一个
 match(value) {
 if (this.lookahead.value === value) {
 this.read();
 return value;
 }
 throw `syntax error @line ${this.lookahead.lineNo} : expect ${value} here but ${this.lookahead.value} found.`;
 }
 //校验类型(静态语言),并向前读一个
 matchType(type) {
 if (this.lookahead.type === type) {
 this.read();
 }
 throw 'syntax error';
 }
 //解析表达式
 parseExpr() {
 return new exprParser_1.expressionParser(this).exprParser();
 }
 /**
 * Stmts -> Stmt Stmts | ε
 */
 parseStmts() {
 const stmts = [];
 while (this.lookahead.type !== 'eof' && this.lookahead.value !== '}') {
 stmts.push(this.parseStmt());
 }
 return stmts;
 }
 /**
 * Program -> Stmts
 */
 parseProgram() {
 return new statement_1.Program(this.parseStmts());
 }
 /**
 * Stmt -> AssignExpr | IfStmt | WhileStmt | Function | Block | ...
 * AssignExpr -> var <id> = Expr
 * IfStmt -> if Expr Block else IfStmt | if Expr Block | Stmt
 */
 parseStmt() {
 if (this.lookahead.type === 'id' || this.lookahead.type === 'number') {
 return this.parseExpr();
 }
 switch (this.lookahead.value) {
 case 'var':
 return this.parseDeclareStmt();
 case 'function':
 return this.parseFunctionStmt();
 case 'if':
 return this.parseIfStmt();
 case 'return':
 return this.parseReturnStmt();
 default:
 console.log(this.lookahead);
 throw `syntax error @line ${this.lookahead.lineNo} : not impl. ${this.lookahead.value}`;
 }
 }
 parseBlock() {
 this.match('{');
 const stmts = this.parseStmts();
 this.match('}');
 return new statement_1.Block(stmts);
 }
 /**
 * FunctionStmt -> function {id}(...ARGS) BLOCK
 */
 parseFunctionStmt() {
 this.match('function');
 if (this.lookahead.type !== 'id') {
 throw 'syntax error';
 }
 const id = this.lookahead.value;
 this.match(id);
 this.match('(');
 const args = this.parseFuncArguments();
 this.match(')');
 const block = this.parseBlock();
 return new statement_1.Function(new terminal_1.Identifier(id), args, block);
 }
 /**
 * ReturnStmt -> return Expr
 */
 parseReturnStmt() {
 this.match('return');
 const expr = this.parseExpr();
 return new statement_1.ReturnStmt(expr);
 }
 /**
 * Args -> <id> | <id>,Args | ε
 */
 parseFuncArguments() {
 let list = [];
 if (this.lookahead.type === 'id') {
 const id = this.lookahead.value;
 this.match(id);
 list.push(new terminal_1.Identifier(id));
 if (this.lookahead.value === ',') {
 this.match(',');
 list = list.concat(this.parseFuncArguments());
 }
 }
 // else {
 // return []
 // }
 return new expression_1.Args(list, 'function');
 }
 /**
 * fn(args)函数调用的参数解析
 */
 parseArguments() {
 let list = [];
 let expr = null;
 while ((expr = this.parseExpr())) {
 list.push(expr);
 }
 return new expression_1.Args(list);
 }
 /**
 * IfStmt -> if Expr Block | if Expr Block else IfStmt | if Expr Block else Block
 */
 parseIfStmt() {
 this.match('if');
 const expr = this.parseExpr();
 const ifBlock = this.parseBlock();
 if (this.lookahead.value === 'else') {
 this.match('else');
 // @ts-ignore
 if (this.lookahead.value === 'if') {
 const ifStmt = this.parseIfStmt();
 return new statement_1.IfStmt(expr, ifBlock, ifStmt);
 }
 else {
 const elseBlock = this.parseBlock();
 return new statement_1.IfStmt(expr, ifBlock, null, elseBlock);
 }
 }
 else {
 return new statement_1.IfStmt(expr, ifBlock);
 }
 }
 /**
 * DeclareStmt -> var id = expr
 */
 parseDeclareStmt() {
 this.match('var');
 if (this.lookahead.type !== 'id') {
 throw 'syntax error';
 }
 const id = new terminal_1.Identifier(this.lookahead.value);
 this.match(this.lookahead.value);
 this.match('=');
 const right = this.parseExpr();
 return new statement_1.DeclareStmt(id, right);
 }
 /**
 * factor -> number | string | id
 */
 parseFactor() {
 if (this.lookahead.type === 'number') {
 const value = this.match(this.lookahead.value);
 return new terminal_1.Numeral(value);
 }
 else if (this.lookahead.type === 'id') {
 const value = this.match(this.lookahead.value);
 if (this.lookahead.value === '(') {
 this.match('(');
 const args = this.parseArguments();
 this.match(')');
 return new expression_1.FunctionCallExpr(new terminal_1.Identifier(value), args);
 }
 else if (this.lookahead.value === '=') {
 this.match('=');
 const expr = this.parseExpr();
 return new expression_1.AssignExpr(new terminal_1.Identifier(value), expr);
 }
 return new terminal_1.Identifier(value);
 }
 else if (this.lookahead.type === 'string') {
 throw 'not impl.';
 }
 else {
 throw `syntax error, expect a factor but ${this.lookahead.value} found`;
 }
 }
 }
 exports.Parser = Parser;
});
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