yacc grammar and types

Who is the responsability of checking semantic value of a program? The
grammar parser or the interpreter/compiler itself. For example


Should i do it this way:


%union
{
int integer;
float real;
}


%token <integer> INT
%token <real> REAL


%%


expr : | INT
              | REAL
              | expr + expr
              | expr - expr
          ;




or should i use something like:


  expr : NUM
              | expr + expr { /* here i would determine the semantics of the
                                            expressions if it was a float or a int */ }
              | expr - expr
            ;




(used a very simple example)


Basically the question is, who has the burden of watching the semantics,
the parser or the "user" code.


--
                                                  Tiago Umm Pascoal
                                              l41484@alfa.ist.utl.pt
[You can do it either way. Which is easier or better depends on the language
you're parsing. -John]
--

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