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From: ejp@bohra.cpg.oz (Esmond Pitt)
Newsgroups: comp.lang.c,comp.unix.wizards
Subject: Re: Lex and initial start conditions
Message-ID: <116@bohra.cpg.oz>
Date: 31 May 90 05:07:00 GMT
References: <6342@crabcake> <1990May30.174745.1161@csrd.uiuc.edu>
Reply-To: ejp@bohra.cpg.oz.au (Esmond Pitt)
Organization: Computer Power Group, Melb, Australia
Lines: 24

In article <1990May30.174745.1161@csrd.uiuc.edu> pommu@iis.ethz.ch (Claude Pommerell) writes:
>
>There is a way to solve your problem, Jack.

There are two even simpler ways.

Instead of effectively changing the initial condition to <Text>, either:

1. Ensure each start-state is equipped with enough rules to handle any
possible input, and, as the documentation does state, place all the
unlabelled rules after all the labelled rules, and/or

2. Label all the rules you only want applied in the INITAL state with
<INITIAL>, so they won't be applied as defaults in other states.

Placing non-labelled rules before labelled rules is probably the single
most common error in writing LEX scripts, even after 15 years.

I don't know why.


-- 
Esmond Pitt, Computer Power Group
ejp@bohra.cpg.oz
D