Re: define-void-function or define-procedure ?

[Carl Sorensen]

On 10/19/11 3:26 AM, "David Kastrup" <address@hidden> wrote:

>Štěpán Němec <address@hidden> writes:
>
>> On Wed, 19 Oct 2011 10:22:09 +0200
>> David Kastrup wrote:
>>
>>> What would people prefer for creating a Lilypond function that returns
>>> an "unspecified" value (what the Guile read-eval-print loop takes as a
>>> hint to print nothing at all) and is called for its side effect?
>>>
>>> define-void-function or define-procedure?  The first is a bit more
>>> C-ish, the second more Pascal-ish.  I am not going to consider
>>> define-subroutine though.
>>
>> Given that in the Scheme world, "procedure" is the standard term for
>> functions in general, `define-procedure' would IMO be a rather
>> unfortunate name for something used to define _only_ that subset of
>> procedures which return an unspecified value, if that's what you mean.
>
>Ok.  Now unfortunately, Guile has a number of functions that one would
>expect to return SCM_UNSPECIFIED, but which return something else.

><snip>

>  There is also
>\ignore #(hashq-set! ...
>but it sounds a bit like nothing would happen.
>\do #(hashq-set! ...
>looks nice, but due to namespace pollution, it is already taken by
>Guile, quite like \eval.
>
>All in all, I can't think of anything better than \ignore.  An
>alternative syntax like ##(...) or ##[...] seems a bit too sneaky to
>me.  One other possibility would be \void.  It might look a bit nicer:
>
>\void #(hashq-set! ...)
>\void #(hashq-set! ...)
>
>rather than
>
>\ignore #(hashq-set! ...)
>\ignore #(hashq-set! ...)
>
>It's a bit C-ish, but not all that bad, and it fits with
>define-void-function.

\returnUnspecified #(hashq-set! ...)

\scmUnspecified #(hashq-set! ...)

\ignoreReturn #(hashq-set! ...)

After all I can think of, I think \void is probably the best.

Thanks,

Carl