Re: How to detect a procedure

[Bruce Korb]

Rob Browning wrote:

> > How about adding this procedure.  I confess to being uncertain if it
> > actually works, I get lost trying to decipher the maze of macros.
> 
> Why this over "defined?"?
> 
> Not opposed, just wanted to make sure I understood the intention.

The scheme scripts for autogen may be written for a version or
environment where a procedure is defined.  Later, someone may run the
script in another environment without that function.  (e.g., with
a retrograde autogen)  So, yes, ``(defined? 'mumble)'' is probably
adequate.  I don't care a whole lot for "probably adequate".  So,
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.
It's a more rigorous test (though it can still be fooled).
[[It saves typing two characters, too.  ;-)  **joke!!**]]

A similar scheme could have replaced the myriad of
"procedure?" "pair?" "struct?" "symbol?" ... procedures
so you would automatically have such a function available
for any new class.  Too late now, methinks.