[antlr-interest] Please advice about float

[Mark Kattenbelt]

I understand your point and agree that perhaps the implication is not 
ideal. However in my parser I want to sometimes parse INT's and other 
times REAL's and not NUMBER's that can be either.

So how do I avoid using => but still having the benefit of having the 
actual INT and REAL token. Is that possible in Geviks original lexer? 
I'm a bit unsure. I do remember being stuck on this before.

Surely this is a common problem, unless of course I'm being stupid and 
see a problem where there isn't one.

Mark

>Yes, and that works too; because I write in C++, I avoid "=>"
>predicates because they incur a thrown exception - very expensive in
>C++ - and in this case you don't really need it.
>
>For java, I understand exceptions are not expensive, so this would
>perhaps work as well.
>
>On 9/19/05, Mark Kattenbelt <mark.kattenbelt at gmail.com> wrote:
>  
>
>>My solution:
>>
>>REAL_OR_INT
>>    : ( INT '.' ) => REAL { $setType(REAL); }
>>    | ('-' INT '.' ) => REAL { $setType(REAL); }
>>    | INT { $setType(INT); }
>>    ;
>>
>>protected INT options { paraphrase = "a constant integer"; }
>>    : ('0' .. '9')+
>>    ;
>>
>>protected REAL options { paraphrase = "a floating point value"; }
>>    : ('-')? INT '.' INT
>>    ;
>>
>>Hope it helps,
>>
>>Mark Kattenbelt
>>    
>>
>
>  
>