如何识别Lex文件中的字符串 [英] How to recognize string in Lex file

问题描述

什么样的方法适合识别lex中的字符串.

Hi what would be appropriate to recognize string in a lex.

我已经尝试过

enter code here

import java_cup.runtime.*;

%%
%cup
%line
NUM = [0-9]
ID = [a-zA-Z]
Pun= [:=;#@$^~]
WhiteSpace = [ \t\r\n\f]
SDQuo = [\"]
%%


({SDQuo}+) ({ID}|{NUM})* ({SDQuo}+) { return new Symbol(sym.STR, new String(yytext()));}

，但是宏无法识别. 我一直收到的错误消息是: 处理第一部分-用户代码. 处理第二部分-JLex声明. 处理第三部分-词汇规则. 创建NFA机器表示. 错误:第39行的解析错误. 说明:词法操作开始时缺少大括号. 解析错误.

but the macro fail to be recognized. The error message that I kept getting is: Processing first section -- user code. Processing second section -- JLex declarations. Processing third section -- lexical rules. Creating NFA machine representation. Error: Parse error at line 39. Description: Missing brace at start of lexical action. Parse error.

推荐答案

在NUM等的定义中松开=符号，不要将它们放在%%之间.而是将最后一个规则放在%%之间.

Loose the = signs in the definitions of NUM etc. and don't place them between %%. Instead place the last rule between %%.

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