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From: firth@sei.cmu.edu (Robert Firth)
Newsgroups: comp.compilers
Subject: Re: Can Pascal be parsed by LR(1) parsing algorithm?
Keywords: pascal, parse
Message-ID: <9094@fy.sei.cmu.edu>
Date: 17 Oct 90 19:10:36 GMT
References: <9010091533.AA02386@apple.com> <1990Oct10.133752.14930@ncsuvx.ncsu.edu>
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Reply-To: firth@sei.cmu.edu (Robert Firth)
Organization: Software Engineering Institute, Pittsburgh, PA
Lines: 16
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In article <1990Oct10.133752.14930@ncsuvx.ncsu.edu> mauney@eos.ncsu.edu (Jon Mauney) writes:

>Berkeley Pascal was, for some time, unable to accept a null
>statement in the "then" clause:
>
>	if i<0 then else foo(i);

But that is not legal Pascal.  The relevant syntax (Wirth, section 9.2.2.1)
reads
	<if-statement> ::= IF <expression> THEN <statement> |
			   IF <expression> THEN <statement> ELSE <statement>

and there is no production from <statement> that yields <empty>.
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