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Re: How to detect a procedure


From: Rob Browning
Subject: Re: How to detect a procedure
Date: Tue, 30 Apr 2002 21:35:40 -0500
User-agent: Gnus/5.090006 (Oort Gnus v0.06) Emacs/21.2 (i386-debian-linux-gnu)

Bruce Korb <address@hidden> writes:

> I would like:
>
>   (defined-as? 'mumble scm_class_procedure)
>
> to be equivalent to:
>
>   (and (defined? 'mumble) (procedure? mumble))
>
> but the latter is conceptually simpler.  I like simple.

or if you really like the idea of a helper, perhaps (nb: not tested,
or even carefully checked :>):

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

i.e.

  (defined-as? 'mumble procedure?)

-- 
Rob Browning
rlb @defaultvalue.org, @linuxdevel.com, and @debian.org
Previously @cs.utexas.edu
GPG=1C58 8B2C FB5E 3F64 EA5C  64AE 78FE E5FE F0CB A0AD



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