Path: utzoo!attcan!uunet!lll-winken!ncis.llnl.gov!helios.ee.lbl.gov!nosc!ucsd!rutgers!mailrus!purdue!decwrl!decvax!ima!compilers-sender From: waterloo.edu!cognos!rayt@RELAY.CS.NET (R.) Newsgroups: comp.compilers Subject: Re: Why can't we build a C compiler? Message-ID: <3227@ima.ima.isc.com> Date: 25 Jan 89 22:38:21 GMT References: <3210@ima.ima.isc.com> Sender: compilers-sender@ima.ima.isc.com Reply-To: "R." Organization: Cognos Inc., Ottawa, Canada Lines: 27 Approved: compilers@ima.UUCP In article <3210@ima.ima.isc.com> Greg Cowin, in reference to C, indicates that semantics is a major problem in ANY language definition, since the present methods of its specification are either informal or "complex and arcane"; one can hardly disagree. However, he continues, "[i]n fact, to some degree the grammar is insignificant. Formalization of syntax is a simpler problem than the formalization of semantics." My comment here is that one method of defining the semantics is THROUGH a grammar; in my case, Van Wijngaarden grammars, which allow one full recursively ennumerable capabilities. A major problem with such systems is efficiency; but techniques are becoming available which allow the parsing of such grammars in polynomial time. The theoretical power is available, but it seems the trick is to actually FIND such a grammar definition for normal programming languages. This is an area of present research. Ray Tigg 3755 Riverside Dr. Cognos Incorporated Ottawa, Ontario (613) 738-1440 x5013 CANADA K1G 3Z4 UUCP: uunet!mitel!sce!cognos!rayt -- Send compilers articles to ima!compilers or, in a pinch, to Levine@YALE.EDU Plausible paths are { decvax | harvard | yale | bbn}!ima Please send responses to the originator of the message -- I cannot forward mail accidentally sent back to compilers. Meta-mail to ima!compilers-request