Hi!
> Le 25 août 2015 à 14:20, Slava Barinov <raysl...@gmail.com> a écrit :
>
> Hello,
>
> I'm experimenting with bison+flex and met an issue: bison won't provide a
> token type info. So the situation: I've got a calc++ example and started to
> simplify it. For example there are two operations + and - which will increase
> and decrease global variables (no arguments needed) so there are lines in
> lex.ll
>
> "+" return yy::parser::make_INC(loc);
> "-" return yy::parser::make_DEC(loc);
>
> and corresponding
>
> %define api.token.constructor
> %define api.value.type variant
> %define parse.assert
> ...
>
> %token INC DEC
> ...
> stmts: stmt {};
> | stmts stmt {};
> ;
> stmt: op
> ;
> op: val_op
> ;
> val_op: INC {driver.addOp($1);}
> | DEC {driver.addOp($1);}
> ;
>
> in parse.yy.
>
> Parser generation is fine, I get the line in parse.cpp:
> driver.addOp(yystack_[0].value);
>
> And after running the debug output prints
> $1 = token INC (1.187-188: )
>
> but the yytypeid_ in variant coming to addOp is zero. So `as<token>()' is not
> applicable (segfault) and I can't detect which token it is. Should the token
> constructor work for such cases or it's designed only for tokens followed by
> arguments?
Your scanner looks fine. You grammar however does not: INC and DEC
are valueless, yet you tried to read from them here:
val_op:
INC {driver.addOp($1);}
| DEC {driver.addOp($1);}
Either give a value to them, or simply use the fact that you do know
in which case you are here. For instance.
val_op:
INC {driver.addOp('+');}
| DEC {driver.addOp('-');}
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