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Path: utzoo!mnetor!uunet!husc6!spdcc!m2c!frog!john
From: john@frog.UUCP (John Woods, Software)
Newsgroups: comp.unix.wizards
Subject: Re: Do start conditions work in lex?
Message-ID: <1635@frog.UUCP>
Date: Tue, 22-Sep-87 20:59:00 EDT
Article-I.D.: frog.1635
Posted: Tue Sep 22 20:59:00 1987
Date-Received: Fri, 25-Sep-87 06:45:51 EDT
References: <6@radix>
Organization: Superfrog Heaven [ CRDS, Framingham MA ]
Lines: 27
Keywords: lex, bug
Summary: Yes, so does precedence

In article <6@radix>, jimv@radix (Jim Valerio) writes:
> 	%start Z
> 	%%
> 	0 		{ printf("0\n"); BEGIN Z; }
> 	1		{ printf("shouldn't get here!\n"); }
> 	<Z>1		{ printf("1\n"); }
> 	.		{ printf("Error! (%c)\n", yytext[0]); }
> 
Two keys from the LEX documentation:
(1) Rules with no start condition are always active.
(2) When two rules match the same input string, the first is preferred.

Try changing your rules to

	%start Z
	%%
	0 		{ printf("0\n"); BEGIN Z; }
	<Z>1		{ printf("1\n"); }
	1		{ printf("shouldn't get here!\n"); }
	.		{ printf("Error! (%c)\n", yytext[0]); }


--
John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101
...!decvax!frog!john, ...!mit-eddie!jfw, jfw@eddie.mit.edu

Maybe it's the sound of a WET RAG hitting a smooth WEASEL!