Re: When to use SCM_DEFINE vs SCM_GPROC vs SCM_PRIMITIVE_GENERIC?

[Andy Wingo]

Hi Mark,

On Fri 28 Jan 2011 01:47, Mark H Weaver <address@hidden> writes:

> I notice that numbers.c uses three different macros to define public
> procedures: SCM_DEFINE, SCM_GPROC, and SCM_PRIMITIVE_GENERIC.  I don't
> see an obvious logic to the choices of which macro to use.  For
> example, `exact->inexact' uses SCM_GPROC whereas `inexact->exact' uses
> SCM_DEFINE.

Yeah, I have no idea why exact->inexact would be extensible and
inexact->exact is not.  (And perhaps we should deprecate those functions
in favor of the R6RS spelling, `inexact' and `exact'.  Another topic.)
And I don't recall the practical difference between GPROC and
PRIMITIVE_GENERIC.

> What macro do you think I should use for the functions I'm writing?
> Note that `div-and-mod' and `div0-and-mod0' will return two values.

For now, SCM_DEFINE.  We can change that later to PRIMITIVE_GENERIC if
needed.

> One more question: do you think I should give div/mod/div0/mod0 their
> short R6RS names by default?

Yes, I think.  At least I remember coming to that conclusion at one
point, before I had to move away from that work.  We might want opcodes
for some of these, also.

Andy
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