Re: Token redefinition

[Bob Smith]

On 11/17/2006 5:52 AM, Hans Aberg wrote:
> On 17 Nov 2006, at 10:05, Tim Van Holder wrote:
>
> > > > I need to write a simple compiler for a pascal-like linguage, using
> > > > flex and bison.
> > > > The language uses token as "INT" "BOOL" or "FALSE"; when I compile the
> > > > project using
> > > > Visual Studio 6.0 the following message is displayed:
> > > >
> > > > "'BOOL' : redefinition; typedef cannot be overloaded with any other
> > > > symbol"
> > > >
> > > > This is because in windef.h they are other defines of tokens "INT"
> > > > "BOOL" or "FALSE".
> > > > How can I resolve the question WITHOUT change the names of the 
> > > > tokens ??
> > >
> > > You can switch to a different platform.
> >
> > Or, as a more constructive suggestion, you could use a prefix for the
> > token names in the grammar (T_BOOL, tBool, tokBOOL, etc. are all viable
> > alternatives).  And you can always give them string names you use in the
> > grammar:
> >
> > grammar:   %token t_BOOL "BOOL"
> > lexer:     "BOOL" { return t_BOOL; }
> > grammar:   some_rule: some_other_rule "BOOL";
> >
> > which ensures that bison syntax errors say they expect a BOOL rather
> > than a t_BOOL (only the lexer has to use the t_* names). This is
> > especially nice when the name for the token consists of multiple words:
> >
> > %token t_DECIMAL_LITERAL "decimal literal"
>
> You probably did not read the OP, who wants the macro names unchanged! 
> The question seems to be how to avoid name clashes without changing 
> their names. :-)

How about #undef BOOL, etc.?

--
_______________________________________________________________
Bob Smith - address@hidden - http://www.sudleyplace.com

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