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From: steven@mcvax.UUCP
Newsgroups: sci.lang,comp.lang.misc
Subject: Re: Using C to describe itself
Message-ID: <7360@boring.mcvax.cwi.nl>
Date: Wed, 22-Apr-87 11:23:51 EST
Article-I.D.: boring.7360
Posted: Wed Apr 22 11:23:51 1987
Date-Received: Fri, 24-Apr-87 02:02:49 EST
References: <437@haddock.UUCP> <1829@enea.UUCP> <440@haddock.UUCP> <1403@uwmacc.UUCP>
Reply-To: steven@cwi.nl (Steven Pemberton, or try steven@mcvax.uucp)
Organization: CWI, Amsterdam
Lines: 16
Xref: utgpu sci.lang:492 comp.lang.misc:359

In article <1403@uwmacc.UUCP> edwards@unix.macc.wisc.edu.UUCP (mark edwards) writes:
>   Yes indeed C can describe itself.

Actually, I'm not completely convinced of this. The question of whether C
can be used to describe itself or not seems to be the same as whether the
sentence "This sentence is true" is true or false: it depends on your
assumptions.

Evidence of this is in Dennis Ritchie's Turing award lecture: he had built a
trojan horse into the C compiler. The compiler looked identical to its
previous self, but actually compiled a (slightly) different language. This
suggests to me that you can't look at the compiler source to determine what
a certain construct in C means, even if you know the meaning of the language
it compiles to.

Steven Pemberton, CWI, Amsterdam; steven@cwi.nl or try steven@mcvax.uucp