Re: [Chicken-users] C_truep( C_fixnump( w ))

[Kon Lovett]

On Feb 25, 2008, at 5:55 AM, felix winkelmann wrote:

> On Mon, Feb 25, 2008 at 1:28 PM, Heinrich Taube <address@hidden>  
> wrote:
> > thank you both very much. just to be sure:
> >
> >  (1) should i be using a C_truep() around C_immediatep() like the  
> > other
> >  predicate tests or is this ok:
> >
> >         if ( C_immediatep(w) ) {
> >            if ( C_truep(C_fixnump(w)) ) {
> >                ...
> >            }
> >
> >         else if  ( C_truep(C_blockp(w)) && C_truep( C_flonump 
> > ( w ) )) {
>
> Yes, this is correct. It is obviously inconsistent, but  
> C_immediatep was
> intended to be used from C and C_fixnump from compiled code.
> Changing this will break old (compiled) code.

I didn't bother to check for immediate or block since

1) We assume it is a Chicken numeric value

2) An immediate value is an invalid address of a block/special item

3) So checking 1st for a fixnum & then for flonum is enough

but real argument checking should be more stringent than my example.

> >  (2) how can i test for strictly #f #t boolean value inside the
> >  immedatep clause?
>
> (x == C_SCHEME_FALSE || x == C_SCHEME_TRUE)


#define C_truep(x)                 ((x) != C_SCHEME_FALSE)

Most of the C_*p are wrapped in a C_mk_bool which is why I used  
C_truep for the test.

> cheers,
> felix
>
>
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Best Wishes,
Kon