如何在Flex中定义布尔值 [英] How to define a boolean in Flex

问题描述

我正在为玩具Java语言(Decaf)构建编译器，但在定义布尔值时遇到了麻烦.当我尝试分析布尔值时，无论我是否写错，它总是返回false.

弹性代码:

I am building a compiler for a toy Java language (Decaf) and I am having trouble with defining a bool. When I try to analyze a boolean, it always returns false, whether or not I wrote false.

Flex code:

true|false  {
            yylval.boolConstant = yytext;
            return T_BoolConstant;
        }

输入代码:

Input code:

bool x = true;
bool y = false;

输出:

Output:

true         T_BoolConstant (value = false)
false        T_BoolConstant (value = false)

我尝试在SO上进行搜索，但这是我能得到的最接近的正确答案:

在Bison中使用C模拟布尔值

谢谢！

EDIT :输出被编码在一个单独的c文件中，该文件打印在测试代码中找到的字符串，它是什么类型的值(在这种情况下，它是boolean或BooleanConstant)，然后是保存的令牌.抱歉造成任何混乱.

I tried searching on SO but this was the closest I could get to a proper answer:

Simulating Booleans in Bison with C

Thank you!

EDIT: The output is coded in a separate c file that prints the string found in the test code, what kind of value it is (in this case it is a boolean or BooleanConstant) and then the value of the token that was saved. Sorry for any confusion.

推荐答案

我相信您需要将字符串"true"和"false"转换为布尔常量true和false.否则，您只是存储字符串.

I believe you need to convert the strings "true" and "false" into the boolean constants true and false. Otherwise you're just storing strings.

true {
    yylval.boolConstant = true;
    return T_BoolConstant;
}

false {
    yylval.boolConstant = false;
    return T_BoolConstant;
}

这是一个具有不同方法的类似问题.

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