Newsgroups: comp.text
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: !'\\$1'' vs. \w'\\$1' in TROFF
Message-ID: <1989Aug16.155455.20836@utzoo.uucp>
Organization: U of Toronto Zoology
References: <2658@aplcen.apl.jhu.edu>
Date: Wed, 16 Aug 89 15:54:55 GMT

In article <2658@aplcen.apl.jhu.edu> bink@aplcen.apl.jhu.edu (Ubben Greg) writes:
>What are the advantages and disadvantages of using
>	.if \w'\\$1' ...
>instead of
>	.if !'\\$1'' ...
>in DWB 2.0 DiTroff macros? ...

They're two different things.  The first asks if the width of the string
is non-zero.  The second asks whether there are any characters in it.
Remember that there are such things as zero-width characters.  People who
use the first form to test for an empty string have goofed.
-- 
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1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu