Unions in semantischen Werten

Id: union.tex,v 1.1 2007-11-20 08:07:45 waldmann Exp

%union {
double     val;  /* Zahlen */
symrec  *tptr;   /* Symboltabellen-Eintrag */
}
%token <val>  NUM 
%token <tptr> VAR FNCT
%type  <val>  exp
%%
exp: NUM         { $$ = $1; }
 | VAR         { $$ = $1->value.var; }
 | VAR '=' exp { $$ = $3; $1->value.var = $3;}
 | FNCT '(' exp ')' 
        { $$ = (*($1->value.fnctptr))($3); }
 | exp '+' exp { $$ = $1 + $3; }