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From: throopw@dg_rtp.UUCP (Wayne Throop)
Newsgroups: net.lang.c
Subject: Re: What should be added to C
Message-ID: <385@dg_rtp.UUCP>
Date: Wed, 4-Jun-86 17:08:12 EDT
Article-I.D.: dg_rtp.385
Posted: Wed Jun  4 17:08:12 1986
Date-Received: Sat, 7-Jun-86 00:19:01 EDT
References: <1462@mmintl.UUCP> <5498@alice.uUCp> <1497@mmintl.UUCP> <450@cad.BERKELEY.EDU> <1518@mmintl.UUCP>
Lines: 28
Summary: #begdef is a puny change compared to #if sizeof

> franka@mmintl.UUCP (Frank Adams)
>> faustus@cad.UUCP

>>You can write arbitrarily large macros by putting backslashes at the end of
>>lines.  This is ugly but it works.
>
> This doesn't let you use "#if" in the body of the macro, as my example would
> require.  To fully explicate, my example would be:
>
> #begdef copy(to, from, number)
> #if sizeof(from) % WORD_SIZE == 0
>    copyword(to, from, number * sizeof(from) / WORD_SIZE)
> #else
>    strncpy(to, from, number * sizeof(from))
> #endif
> #enddef

Along with multi-line-ness, this example has snuck in a *very* large
change in the language.  In particular,

        #if sizeof(from)

In order to evaluate this, the preprocessor would need to know (oddly
enough) the size of "from".  Since the preprocessor currently does not
even know full C syntax, this is a *very* radical change in the
language.
-- 
Wayne Throop      <the-known-world>!mcnc!rti-sel!dg_rtp!throopw