[cfe-dev] changing the lexer or parser

steve naroff snaroff at apple.com
Tue Sep 9 15:01:52 PDT 2008

Hi Bas,

clang currently implements C integer constants by including the  
trailing suffix (see C99 for more details).

Sema::ActOnNumbericConstant() is then responsible for determining the  
type of constant (integer, floating) and size.

I haven't thought about adapting clang's lexer to generate tokens that  
don't conform to C.

That said, you could simply examine the "suffix" by hand (without  
fiddling with the lexer directly).


On Sep 9, 2008, at 5:27 PM, b.j.burgers at student.utwente.nl wrote:

> Hello,
> I’m working on a tool that allows time construct in C. I implemented  
> this tool by adapting Clang.
> In these time constructs I like to allow arguments like “1000s”,  
> “1000 s”, “1000  s”, “100ms”, “100 ms”, etc.
> The lexer creates 1 token called numerical_token if the argument is  
> “1000s” even if ‘s’ is added as keyword or token in TokenKinds.def.  
> I hoped the lexer would have generated two tokens, 1  
> numerical_constant and an identifier (or self defined token).
> What is the best way to allow these kind of arguments ? Do I have to  
> create a new token that allows some digits followed by an ‘s’?
> Thanks for any help,
> Bas Burgers
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev

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