From ...
From: Erik Naggum <erik@naggum.no>
Subject: Re: A portable DIRECTORY-P. Re: Here we go again. More CMUCL/ACL pathname differences.
Date: 1999/01/12
Message-ID: <3125142331394422@naggum.no>#1/1
X-Deja-AN: 431683970
References: <778kqn$2b2$1@nnrp1.dejanews.com> <efyyanagarp.fsf@whizzy.cc.gatech.edu> <77bdqi$9fk$1@nnrp1.dejanews.com> <3125045622004774@naggum.no> <77e4e3$jrj$1@nnrp1.dejanews.com> <87d84lpaxr.fsf_-_@2xtreme.net>
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Organization: Naggum Software; +47 8800 8879; http://www.naggum.no
Newsgroups: comp.lang.lisp

* cbarry@2xtreme.net (Christopher R. Barry)
| I'd like to have a LOGICAL-PATHNAME-P so that I could know that the
| argument I pass to TRANSLATE-LOGICAL-PATHNAME won't give an error.
| Anyone got a flash of insight as to how to implement this?

(defun logical-pathname-p (pathname)
  (typep pathname 'logical-pathname))

  chances are the function already exists if PATHNAME and LOGICAL-PATHNAME
  are both structures defined with DEFSTRUCT, and you just need APROPOS to
  find it.  there's nothing inherently evil in using non-exported functions
  or functions not in the COMMON-LISP package.  you just need to know what
  you are doing.  that's never a bad thing.

#:Erik