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Path: utzoo!utcsri!greg
From: greg@utcsri.UUCP (Gregory Smith)
Newsgroups: net.lang.c
Subject: Re: Datalight faster than 4.2, why?
Message-ID: <2912@utcsri.UUCP>
Date: Wed, 4-Jun-86 12:20:01 EDT
Article-I.D.: utcsri.2912
Posted: Wed Jun  4 12:20:01 1986
Date-Received: Wed, 4-Jun-86 12:25:11 EDT
References: <1723@umcp-cs.UUCP> <3844@sun.uucp>
Reply-To: greg@utcsri.UUCP (Gregory Smith)
Organization: CSRI, University of Toronto
Lines: 26
Summary: 

In article <3844@sun.uucp> guy@sun.uucp (Guy Harris) writes:
>> And again, we would still need a separate cpp to make the kernel,
>
>Well, note that if a "cc" is to be considered a real UNIX "cc", it will have
>to support "-P" and "-E".  This means that if you don't have a separate
>preprocessor, there will have to be *some* way of running just the
>preprocessor part of the lexical analyzer and getting compilable C output
>from it.  (Sorry, any of you people who want to bundle "cpp" and the lexical
>analyzer, but that's the way it is.)  Given that, you can either hack "cc"

Bee's Knees.
Any c compiler with an integral cpp will have a function 'inchar()' ( or
possibly a macro for speed ) which is called from the lexer to get the
next input char from the cpp. In effect, 'inchar()' runs the cpp. So the
-E option is done by the following magnum opus (which of course is also
used to debug the cpp code ):

	while( (c=inchar()) !=EOF ) putc( c, outfile );

Modularity in software design does not imply a separate program for each
module.

-- 
"We demand rigidly defined areas of doubt and uncertainty!" - Vroomfondel
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Greg Smith     University of Toronto      UUCP: ..utzoo!utcsri!greg