Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!bsu-cs!dhesi
From: dhesi@bsu-cs.bsu.edu (Rahul Dhesi)
Newsgroups: comp.lang.misc
Subject: Re: Language Design, or: is C's Grammar Context Free
Keywords: BNF, Grammars, Silliness
Message-ID: <6597@bsu-cs.bsu.edu>
Date: 7 Apr 89 02:07:59 GMT
References: <5200040@m.cs.uiuc.edu> <12443@watdragon.waterloo.edu> <6541@bsu-cs.UUCP> <3718@ficc.uu.net>
Reply-To: dhesi@bsu-cs.UUCP (Rahul Dhesi)
Organization: CS Dept, Ball St U, Muncie, Indiana
Lines: 21

In article <3718@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>If 'c's grammar is context free, and the context sensitivity is in the
>semantics, tell me if the following is a syntax error...

It depends on which context-free grammar you are using.  Here's a
simple one:

program ::= char charlist
charlist ::= .null. | charlist char
char ::= 'a' | 'b' | ... '0' | '1' | ... '#' | '(' | .... blank | tab ... etc.

(.null. means empty string.)

My lexical analyzer always returns a single character or EOF.  My
parser is pretty simple.  There is only one possible error during
parsing:  "premature EOF".

Semantic analysis is a nightmare :-).
-- 
Rahul Dhesi         UUCP:  <backbones>!{iuvax,pur-ee}!bsu-cs!dhesi
                    ARPA:  dhesi@bsu-cs.bsu.edu