From: Jean-Marc Bourguet <jm@bourguet.org>
Subject: Re: Calculator and Operator Precedence
Date: 22 Feb 2002 17:55:49 +0100
Date: 2002-02-22T17:55:49+01:00 [thread overview]
Message-ID: <3c76780d$1@news.cadence.com> (raw)
In-Reply-To: mailman.1014394382.27785.comp.lang.ada@ada.eu.org
"Steven Deller" <deller@smsail.com> writes:
> Interestingly, I just cobbled together Ada code to parse arbitrary Ada
> expressions consisting of just operators, parentheses, and literals (I'm
> probably going to make it handle type conversions as well).
>
> It uses two stacks (one for operands, one for operators), and recursion
> (on parentheses).
Why do you need recursion? Parentheses can be handled with the two
stacks, pushing opening parenthese on the operator stack and applaying
operators till a openening parenthese is on TOS when seeing a close
parenthese.
BTW, This parsing technique can be extented (see weak operator
precedence in the litterature) and has been used quite a lot before
LALR grammar where showed to be usefull.
--
Jean-Marc
next prev parent reply other threads:[~2002-02-22 16:55 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-02-19 16:26 Calculator and Operator Precedence jon
2002-02-19 17:24 ` Stephen Leake
2002-02-19 20:00 ` Matthew Heaney
2002-02-20 8:03 ` Phil Thornley
2002-02-20 15:28 ` Jon
2002-02-20 15:45 ` John English
2002-02-22 16:10 ` Steven Deller
2002-02-22 16:55 ` Jean-Marc Bourguet [this message]
2002-02-25 9:17 ` Dmitry A. Kazakov
2002-02-22 20:14 ` Vadim Godunko
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