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From: stephen@datacube.UUCP
Newsgroups: net.lang.c
Subject: Re: C not LALR(1) & compiler bugs
Message-ID: <7800010@datacube.UUCP>
Date: Mon, 27-Jan-86 10:39:00 EST
Article-I.D.: datacube.7800010
Posted: Mon Jan 27 10:39:00 1986
Date-Received: Thu, 30-Jan-86 05:49:58 EST
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Nf-From: datacube!stephen    Jan 27 10:39:00 1986


> C's grammar is CONTEXT SENSITIVE !?    Can it be ?! ...

C is context sensitive in many ways, but so is just about every other
programming language in existence. PASCAL or MODULA-II, for example,
have an ambiguity for:

Statement ::= assign_stmt | procedure_invocation | ...

assign_stmt ::= IDENTIFIER ':=' expression
procedure_invocation ::= IDENTIFIER ...

This also must be resolved by feedback to the lexer.

In a general sense, any programming language where variables are
declared is context-sensitive, since the semantics of later invocations
of the variable depend on what type the variable was declared.

Really, you are flaming the lack of power of an LALR(n) grammar. However,
due to considerations of efficiency and convenience, an LALR grammar is
probably one of the best choices for parsing a language (especially if
you have yacc available).