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From: Paul_Abrahams@MTS.cc.Wayne.edu
Newsgroups: comp.lang.icon
Subject: Portability
Message-ID: <317920@MTS.cc.Wayne.edu>
Date: 9 Apr 91 17:29:58 GMT
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An example of a portable Icon function with a nonportable
implementation is the file name generator I posted a while back. 
Given a file name with wildcards, its result sequence is the set
of specific file names that match.  The DOS implementation uses a
specific system call, while the Unix implementation (I'd guess)
would use a shell echo call with redirected output (since
wildcard interpretation is generally done in the shell, not in
the underlying system.)  Note that DOS wildcards and Unix
wildcards have somewhat different interpretations: DOS
essentially ignores characters after `*', while Unix doesn't; and
the DOS treatment of the file extension is quite different from
that of Unix.
 
Path name interpretation is another example of a portable
function with a non-portable implementation, since DOS uses `\'
but Unix uses `/' (and maybe the Mac uses something else again). 
But the notion of a path makes sense in any system that has
tree-structured directories.  (Does anyone know how this maps to
the IBM OS/370 world?)
 
Paul Abrahams
Abrahams@mts.cc.wayne.edu