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From: eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout)
Newsgroups: comp.text.tex
Subject: Re: Why use TeX if ...
Keywords: TeX, PostScript, typesetting, page description, programming
Message-ID: <1991May14.170252.1412@csrd.uiuc.edu>
Date: 14 May 91 17:02:52 GMT
References: <1991May10.211802.4344@csrd.uiuc.edu> <1991May11.013248.16286@nntp-server.caltech.edu> <1991May13.214453.17318@csrd.uiuc.edu> <1991May14.121233.11823@ifi.uio.no>
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janl@ifi.uio.no (Nicolai Langfeldt) writes:

>In article <1991May13.214453.17318@csrd.uiuc.edu> eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout) writes:
>...
>>input is the only form of iteration imaginable. Hence no loop
>>constructs. Large parts of the design of TeX follow immediately

>No loop constructs? I seem to remember that there is both \loop and
>\for available. I've even used one of them once!

In ordinary (algorithmic that is) programming languages
a loop is based on a GOTO statement jumping back to
some earlier instruction. TeX's \loop macro doesn't
do that, it inserts the loop body again. Looping five times
is not jumping back four times, it is in effect equal
to having the loop body laid out five times in a row.

Therefore no loop constructs. Merely emulations of them.

Victor.