Re: How to detect a procedure

[Neil Jerram]

>>>>> "Bruce" == Bruce Korb <address@hidden> writes:

    Bruce> Rob Browning wrote:
    >> 
    >> Lynn Winebarger <address@hidden> writes:
    >> 
    >> >>   (defined-as? 'mumble procedure?)
    >> >
    >> >      How about  (defined-as procedure?  'mumble)
    >> > to keep the predicate clear?
    >> 
    >> Looks better to me :>

    Bruce> Me, too :)

But I think Rob's definition was missing a quote.

This works for me:

(define-macro (defined-as predicate symbol)
  `(and (defined? ',symbol)
        (,predicate ,symbol)))

guile> (defined-as procedure? procedure?)
#t
guile> (defined-as procedure? does-not-exist)
#f
guile> (defined-as procedure? defined-as)
#f
guile> (defined-as macro? defined-as)
#t
guile> (defined-as procedure? %load-path)
#f
guile> (defined-as list? %load-path)
#t

        Neil