Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!us.feeder.erje.net!news.linkpendium.com!news.linkpendium.com!news.iecc.com!.POSTED!nerds-end
From: "Costello, Roger L." <costello@mitre.org>
Newsgroups: comp.compilers
Subject: Should data filtering be done while building the parse tree or after the parse tree is built?
Date: Mon, 3 Jun 2013 19:47:07 +0000
Organization: Compilers Central
Lines: 24
Sender: johnl@iecc.com
Approved: comp.compilers@iecc.com
Message-ID: <13-06-005@comp.compilers>
NNTP-Posting-Host: news.iecc.com
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Trace: leila.iecc.com 1370446096 15381 64.57.183.58 (5 Jun 2013 15:28:16 GMT)
X-Complaints-To: abuse@iecc.com
NNTP-Posting-Date: Wed, 5 Jun 2013 15:28:16 +0000 (UTC)
Keywords: parse, question
Posted-Date: 05 Jun 2013 11:28:15 EDT
X-submission-address: compilers@iecc.com
X-moderator-address: compilers-request@iecc.com
X-FAQ-and-archives: http://compilers.iecc.com
Xref: csiph.com comp.compilers:915

Hi Folks,

I am building a parser to parse some data.

I want to filter some of the data.

For example, I want to "fuzz" latitude and longitude values to contain just
two digits to the right of the decimal point.

    Fuzz this latitude value:
          42.3583
    to this:
         42.35

When should filtering be done?

Should I embed filtering rules into the grammar -- perform filtering as I
build the parse tree?

Or, should I build the parse tree and then have an application perform
filtering on the parse tree?

/Roger