Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!rutgers!sun-barr!newstop!sun!imagen!daemon
From: geof@apolling (Geof Cooper)
Newsgroups: comp.lang.postscript
Subject: Re: The // operator
Message-ID: <3903@imagen.UUCP>
Date: 5 Jun 89 22:32:57 GMT
Sender: daemon@imagen.UUCP
Lines: 20

In article <2586@shlump.dec.com> batcheldern@icosa.dec.com (Ned Batchelder) writes:
>The // construct in PostScript is not an operator; it is more like a name modifier. 
>When a name is preceded by the double-slash, its current value is used instead of the
>name.

Software developers, be careful how you use this feature.  It is not
possible to test for the existence of a feature if you want to use // in
relation to it.  For example, the latest Apple LaserPrep contains code
of the form:

	if <I'm a LaserWriter> then
		<do some nifty things with funny operators in serverdict>

This is all very well, but the "nifty thing" references LaserWriter
operators in serverdict using the // convention.  This means that those
names must resolve to valid objects on ALL machines, not just the
LaserWriter, since the names are resolved in the scanner independent
of the result of the conditional.

- Geof