bison中的多个属性 [英] Multiple attributes in bison

问题描述

我在bison中做语义分析，我想使用与一个标记相关联的多个属性。我的代码的相关部分是：

I am doing semantic analysis in bison and i want to use multiple attribute associated with a token. A related part of my code is:

%union semrec
{
    int Type;
    char *id;

}

%start prog

%token <id>  tIDENT

在这里，我只能使用tIDENT标记中的id属性。我还想将Type属性与tIDENT令牌相关联。为此，我尝试了以下操作：

Here, i can only use the "id" attribute witht the tIDENT token. I also want to associate the "Type" attribute with tIDENT token. To do this, i tried the following:

 %token <id>  tIDENT
 %token <Type>  tIDENT

但它给我一个重新声明符号tIDENT的警告。我还尝试了以下操作：

But it gives me a redeclaration warning for token tIDENT. I also tried the following:

 %token <id> <Type> tIDENT

它也无效。我能做什么？我想这只是一个小的句法问题。

It also did not work. What can i do? I think this is just a little syntactic problem.

谢谢。

推荐答案

你不能这样做：你必须以这样的方式定义你的％union ，所有具有多个属性的符号都有 struct 定义所有这些属性。像

You cannot do it this way: you have to define your %union in such a way that all the symbols that have multiple "attributes" have a struct to define all these "attributes". Something like

%union
{
  struct
  {
    int type;
    char *id;
  } type_id;
}
%type <type_id> tIDENT

并使用 $ 1.type code> $ 1.id 等。

and use $1.type or $1.id etc.

注意，我非常怀疑你在做正确的事情。机会很高，你将需要一个AST（抽象语法树）。您应该查找有关信息。

Note however that I very much doubt that you're doing the right thing. Chances are high that you will need an AST (Abstract Syntax Tree). You should look for information about that.

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