[gambit-list] check vs null

lowly coder lowlycoder at huoyanjinjing.com
Sat Feb 14 17:32:17 EST 2009


it works now; thanks!

the main reason I posted to gambit rather than #scheme ... is that this
seems a C-FFI (thus implementation specific question, not a generic scheme
question)

if I'm wrong ... please point out what scheme standard defines how NULLS
from C-FFI/land is handled in scheme?

On Sat, Feb 14, 2009 at 2:26 PM, Marijn Schouten (hkBst)
<hkBst at gentoo.org>wrote:

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> lowly coder wrote:
> > suppose I have c code of:
> >
> > [1] foo *bar = get_foo();
> > [2] if (bar != NULL) { ... }
> >
> >
> >
> > in scheme, I have
> >
> > (let ((bar (get-foo))) [1]
> >   [2] <-- how do I write this line in scheme?
>
> (if bar (do-something-with bar) (do-something-else))
>
>
> (get-foo) should evaluate to #f if there is no bar.
>
> You should give #scheme a try for such basic questions.
>
> Good luck,
>
> Marijn
>
>
> - --
> Sarcasm puts the iron in irony, cynicism the steel.
>
> Marijn Schouten (hkBst), Gentoo Lisp project, Gentoo ML
> <http://www.gentoo.org/proj/en/lisp/>, #gentoo-{lisp,ml} on FreeNode
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