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From: dhesi@rb442.UUCP
Newsgroups: comp.unix.questions
Subject: Re: Teaching Assembler on VAX (BSD 4.3)
Message-ID: <104@rb442.UUCP>
Date: Wed, 10-Jun-87 00:14:15 EDT
Article-I.D.: rb442.104
Posted: Wed Jun 10 00:14:15 1987
Date-Received: Sat, 13-Jun-87 04:12:33 EDT
References: <7447@brl-adm.ARPA> <1658@tekcrl.TEK.COM> <5874@brl-smoke.ARPA> <787@mcgill-vision.UUCP>
Reply-To: iuvax!bsu-cs!dhesi (Rahul Dhesi)
Organization: CS Dept., Ball State University, Muncie, Indiana
Lines: 36
Summary: There is no rational justification for the existence of both m4 and /lib/cpp.

In article <787@mcgill-vision.UUCP> mouse@mcgill-vision.UUCP (der Mouse) writes:
>In article <5874@brl-smoke.ARPA>, gwyn@brl-smoke.ARPA (Doug Gwyn ) writes:
>> Please don't use /lib/cpp except as part of /bin/cc.
>> It is not intended for use as a general macro processor and may
>> indeed go away some day.
...
>> If you need a macro processor on UNIX, use m4.
>
>Except that m4 and cpp address things rather differently.  Until you
>write a macro package for m4 that makes it behave like cpp (and I mean
>exactly like cpp), people will continue to use cpp.

The simultaneous existence of /lib/cpp and m4, both of which do the same 
thing a little differently, has always perplexed me.  

The UNIX philosophy of different tools for different things makes sense.  
Here we have an aberration:  Different things for the same purpose done a 
little differently.  And though m4 is the more powerful package, it is also 
the one with the more convoluted syntax.  I mean, really, look at this:  
define(compare,'ifelse($1, $2, yes, no)').  Most people would rather stick 
with the familiar #if..#else..#endif.

Thus, although m4 is more than you need to teach assembly programming, it
is also more than you deserve to have to cope with.

I note with some interest that AT&T's new make utility includes a mechanism
for decision-making using the syntax of /lib/cpp.  One wonders (but not for
very long) why m4 simply wasn't made a default macro processor for
makefiles.

I think /lib/cpp should be made an official part of UNIX and extended to
cover the cases that only m4 can currently deal with.  Then m4 should be
gracefully moved to a resting place with a nice name like /usr/bin/obsolete
until it fades away.
-- 
Rahul Dhesi         UUCP:  {ihnp4,seismo}!{iuvax,pur-ee}!bsu-cs!dhesi