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From: eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout)
Newsgroups: comp.text.tex
Subject: Re: Explanation requested re: \uppercase and \romannumeral
Message-ID: <1991Jan31.154336.600@csrd.uiuc.edu>
Date: 31 Jan 91 15:43:36 GMT
References: <BRISTER.91Jan30170400@saratoga.decwrl.dec.com>
Sender: news@csrd.uiuc.edu (news)
Organization: UIUC Center for Supercomputing Research and Development
Lines: 20

brister@decwrl.dec.com (James Brister) writes:

>Could someone clue me in why line 1 doesn't work, but line 2 does.

>	1) \uppercase{\romannumeral\count0}
>	2) \uppercase\expandafter{\romannumeral\count0}

It is the definition of \uppercase that it takes a token
list and  uppercases every character token in it.
You wouldn't want the reverse, because then things like
\def\IsUppercaseChar#1{\uppercase{\if#1}#1}
wouldn't work because the \if is expandable.

The second line works because \uppercase has to expand
in order to find its opening brace: that can be implicit.
This in contrast to 
\def\foo\expandafter{\romannumeral 4}
which is *not* the same as \def\foo{iv}

Victor.