Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!adam.pika.mit.edu!scs
From: scs@adam.pika.mit.edu (Steve Summit)
Newsgroups: comp.lang.c
Subject: Re: C optimizer
Summary: use #pragma, not keyword
Keywords: C pure function optimization pragma
Message-ID: <9326@bloom-beacon.MIT.EDU>
Date: 19 Feb 89 01:04:40 GMT
References: <515@larry.UUCP> <9648@smoke.BRL.MIL> <13134@steinmetz.ge.com>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: scs@adam.pika.mit.edu (Steve Summit)
Lines: 17

In article <13134@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes:
>  I agree. One solution would be to provide a keyword, perhaps something
>like 'pure' or 'deterministic', which would indicate...

Just Say No to new keywords.  This sort of optimization is a fine
idea, and it does require a hint to the compiler, for the reasons
already discussed.  However, outside-the-language mucking around
is exactly what #pragmas are for:

	#pragma pure(sin)

(Someone, probably Karl Heuer, already made passing reference to
the use of #pragmas for this example.)  Extra keywords are messy,
even if they do follow the rules and use leading underscores.

                                            Steve Summit
                                            scs@adam.pika.mit.edu