* Real predicate in C
@ 2002-06-09 11:09 Hilaire Fernandes
2002-06-18 22:02 ` Hilaire Fernandes
2002-06-19 11:30 ` Marius Vollmer
0 siblings, 2 replies; 6+ messages in thread
From: Hilaire Fernandes @ 2002-06-09 11:09 UTC (permalink / raw)
It looks like the real? predicate is not implemented in the C interface,
I got the following error when trying to use it:
drgeo_script.cc:141: implicit declaration of function `int gh_real_p(...)'
The number? one is implemented but I need to test for real number and complex.
Any tips?
Hilaire
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* Re: Real predicate in C
2002-06-09 11:09 Real predicate in C Hilaire Fernandes
@ 2002-06-18 22:02 ` Hilaire Fernandes
2002-06-19 4:47 ` Steve Tell
2002-10-04 18:02 ` Thien-Thi Nguyen
2002-06-19 11:30 ` Marius Vollmer
1 sibling, 2 replies; 6+ messages in thread
From: Hilaire Fernandes @ 2002-06-18 22:02 UTC (permalink / raw)
Cc: guile-user
If the gh_real predicate does not exist, what is the proper way to implement it?
Hilaire
On Sun, 9 Jun 2002 13:09:20 +0200
Hilaire Fernandes <hilaire@ext.cri74.org> wrote:
> It looks like the real? predicate is not implemented in the C interface,
> I got the following error when trying to use it:
>
> drgeo_script.cc:141: implicit declaration of function `int gh_real_p(...)'
>
>
> The number? one is implemented but I need to test for real number and complex.
>
> Any tips?
>
> Hilaire
>
> _______________________________________________
> Guile-user mailing list
> Guile-user@gnu.org
> http://mail.gnu.org/mailman/listinfo/guile-user
>
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* Re: Real predicate in C
2002-06-18 22:02 ` Hilaire Fernandes
@ 2002-06-19 4:47 ` Steve Tell
2002-06-19 11:41 ` Marius Vollmer
2002-10-04 18:02 ` Thien-Thi Nguyen
1 sibling, 1 reply; 6+ messages in thread
From: Steve Tell @ 2002-06-19 4:47 UTC (permalink / raw)
Cc: guile-user
On Wed, 19 Jun 2002, Hilaire Fernandes wrote:
> If the gh_real predicate does not exist, what is the proper way to implement it?
Try:
SCM_REALP(scmobj)
Unfortunately, it looks like the only way to learn this is to read
<libguile/numbers.h> (and ignore lots of implementation details).
Or just maybe my last download from http://www.glug.org/docbits/ is too
old.
Steve
> Hilaire
>
> On Sun, 9 Jun 2002 13:09:20 +0200
> Hilaire Fernandes <hilaire@ext.cri74.org> wrote:
>
> > It looks like the real? predicate is not implemented in the C interface,
> > I got the following error when trying to use it:
> >
> > drgeo_script.cc:141: implicit declaration of function `int gh_real_p(...)'
> >
> >
> > The number? one is implemented but I need to test for real number and complex.
> >
> > Any tips?
> >
> > Hilaire
> >
> > _______________________________________________
> > Guile-user mailing list
> > Guile-user@gnu.org
> > http://mail.gnu.org/mailman/listinfo/guile-user
> >
>
> _______________________________________________
> Guile-user mailing list
> Guile-user@gnu.org
> http://mail.gnu.org/mailman/listinfo/guile-user
>
--
--
Steve Tell tell@telltronics.org
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* Re: Real predicate in C
2002-06-19 4:47 ` Steve Tell
@ 2002-06-19 11:41 ` Marius Vollmer
0 siblings, 0 replies; 6+ messages in thread
From: Marius Vollmer @ 2002-06-19 11:41 UTC (permalink / raw)
Cc: Hilaire Fernandes, guile-user
Steve Tell <tell@telltronics.org> writes:
> On Wed, 19 Jun 2002, Hilaire Fernandes wrote:
>
> > If the gh_real predicate does not exist, what is the proper way to implement it?
>
> Try:
> SCM_REALP(scmobj)
That's unfortunately not the same as 'real?' in Scheme. It is only
true for numbers represented as floating point, but is false for
integers, for example. Yes, it's a mess.
> Unfortunately, it looks like the only way to learn this is to read
> <libguile/numbers.h> (and ignore lots of implementation details).
The manual has scm_real_p right next to 'real?'.
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* Re: Real predicate in C
2002-06-18 22:02 ` Hilaire Fernandes
2002-06-19 4:47 ` Steve Tell
@ 2002-10-04 18:02 ` Thien-Thi Nguyen
1 sibling, 0 replies; 6+ messages in thread
From: Thien-Thi Nguyen @ 2002-10-04 18:02 UTC (permalink / raw)
Cc: guile-user
From: Hilaire Fernandes <hilaire@ext.cri74.org>
Date: Wed, 19 Jun 2002 00:02:15 +0200
If the gh_real predicate does not exist, what is the proper
way to implement it?
the proper way to implement it is to add a few lines to
libguile/gh_predicates.c, libguile/gh.h, and add a mention
in the docs. would you like to do this? (in 1.4.x series,
gh_ is not deprecated so extending it compatibly is DTRT.)
thi
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* Re: Real predicate in C
2002-06-09 11:09 Real predicate in C Hilaire Fernandes
2002-06-18 22:02 ` Hilaire Fernandes
@ 2002-06-19 11:30 ` Marius Vollmer
1 sibling, 0 replies; 6+ messages in thread
From: Marius Vollmer @ 2002-06-19 11:30 UTC (permalink / raw)
Cc: guile-user
Hilaire Fernandes <hilaire@ext.cri74.org> writes:
> It looks like the real? predicate is not implemented in the C interface,
> I got the following error when trying to use it:
>
> drgeo_script.cc:141: implicit declaration of function `int gh_real_p(...)'
The 'real?' predicate is available from the scm_ interface, but not
from the gh_ interface.
You can use
SCM_NFALSEP (scm_real_p (OBJ))
to test whether OBJ is a real number. (Note that integers are real too.)
The funny SCM_NFALSEP means "not false?" and must be used since
scm_real_p returns a Scheme boolean (that is, either #t or #f) and not
a C boolean (either 1 or 0).
The SCM_REALP macro only tests whether some number has a floating
point representation, it is not the same as scm_real_p.
(We are not really happy about this situation, either.)
In general, the 'primitive procedures' of the Scheme side are all
available on the C side, in the scm_ interface. The Guile reference
manual talks about this in the "API overview" node.
For example, 'real?' is a primitive procedure and its C name is
"scm_real_p". It takes one SCM argument and returns a SCM result.
You can check whether it is a primitive by printing it from the repl:
guile> real?
#<primitive-procedure real?>
guile> (define (foo) #t)
guile> foo
#<procedure foo ()>
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2002-06-09 11:09 Real predicate in C Hilaire Fernandes
2002-06-18 22:02 ` Hilaire Fernandes
2002-06-19 4:47 ` Steve Tell
2002-06-19 11:41 ` Marius Vollmer
2002-10-04 18:02 ` Thien-Thi Nguyen
2002-06-19 11:30 ` Marius Vollmer
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