2014-06-01 18:45 GMT+02:00 Paul Morris <p...@paulwmorris.com>:
> Paul Morris wrote
>> #(define-music-function (parser location arg)
>> (or (boolean?) (number?) (procedure?))
>> ...)
>
> I suppose it would need to be something like this to work for multiple
> arguments:
>
> #(define-music-function (parser location argA argB)
> ((or boolean? number? procedure?)
> pair?)
> ...)
>
> Anyway, you can see the idea despite my fumbling with the syntax.
>
> -Paul
Hi Paul,
in general I disagree.
Nearly every time I thought I'd need a predicate for multiple
argument-types, I found a way to code it better/simpler.
OTOH, we have already the most general `scheme?'-predicate. You can
use it first and sort the argument-types later.
And really hackish is:
test =
#(define-music-function (parser location test-arg mus)
(
;very bad, kludgy and hacky, though valid:
((lambda (x) (or (boolean? x) (number? x) (procedure? x))) "")
;scheme?
ly:music?
)
(cond ((boolean? test-arg)
(format #t "\n~a is a boolean." test-arg))
((number? test-arg)
(format #t "\n~a is a number." test-arg))
((procedure? test-arg)
(format #t "\n~a is a procedure." test-arg))
(else #f))
mus)
m = { c''1 }
\test ##f \m
\test #3 \m
\test #(lambda (a) a) \m
Cheers,
Harm
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