Path: utzoo!utgpu!watmath!clyde!ima!compilers-sender
From: acw!guthery@uunet.uu.net (Scott Guthery)
Newsgroups: comp.compilers
Subject: Why Can't We Build a C Compiler?
Message-ID: <3070@ima.ima.isc.com>
Date: 18 Dec 88 21:55:38 GMT
Sender: compilers-sender@ima.ima.isc.com
Reply-To: acw!guthery@uunet.uu.net (Scott Guthery)
Lines: 35
Approved: compilers@ima.UUCP

"C is not a `very high level' language, nor a `big' one ...".   Its syntax 
and semantics are well-defined.  A C compiler is probably a relatively small 
and not a particularly complicated computer program.  We have constructed 
a number of very powerful of tools to help us build C compilers.  We have 
an extensive theoretical and practical compiler literature going back at 
least 30 years.  We have tens of thousands of man-years experience in trying 
to build C compilers.  And yet I claim there does not exist a compiler for
the C programming language.  There are a lot of programs that are close but 
close shouldn't count.  Every program I know of which calls itself a C 
compiler is at curent version level greater than 1.00 and will correct a 
couple more bugs in the next release.

Why is this?  What does it say about us and our craft?  Is it even possible 
to build a C compiler?  If so, when do you think there will be one?   How
will we recognize it if it does happen to come into being? 

Finally, if after hundreds of attempts we can't build a little 10,000 line 
utility for ourselves why in the world do we think we can build all the 
programs we work on every day?  We are certainly kidding the folks that 
pay us and we're also doing a pretty good job of kidding ourselves.

+*+*+*+*+*+*+*+*+*+*+*+*+ Austin Code Works +*+*+*+*+*+*+*+*+*+*+*+*+*+*+**+*+
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[This point is well taken.  I would think that with all of the theory
available to compiler writers, compilers would be prime targets for software
engineering techniques such as formal verification, of parts at least.  Beats
me why not.  -John]
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