From: "Oliver Kellogg" <oliver.kellogg@t-online.de>
Subject: Re: GPS - A new kind of IDE?
Date: Tue, 11 Feb 2003 02:24:07 +0100
Date: 2003-02-11T02:24:07+01:00 [thread overview]
Message-ID: <b298nr$9c$06$1@news.t-online.com> (raw)
In-Reply-To: slrnb49n14.ed.randhol+news@kiuk0152.chembio.ntnu.no
I've just bumped into an interesting data point on
parser contruction with ANTLR regarding parse speed.
ANTLR supports syntactic predicates such as
(subprog_body) => subprog_body
where the rule subprog_body is applied on trial
and if it turns out not to apply then the parser backs
out and applies the next rule. Terence Parr, inventor
of ANTLR, calls this "infinite lookahead".
This feature makes for a prettier grammar because
it allows more liberal reuse of rules. In the above
example, we can write the subprog_body rule in a
place where also a subprog_spec could be expected;
the parser takes care of resolving the ambiguity.
However, that beauty has its price.
As a test, I submitted the source code of the
Ada Graphics Package (agp95_v0.1_x11/src) to parsing
(38560 LOC, 11851 executable semicolons.)
With usage of syntactic predicate for the subprog_spec/subprog_body
distinction ("pretty" soft-state grammar rule):
real 1m16.635s
user 1m15.930s
sys 0m0.300s
Without usage of syntactic predicate for the subprog_spec/subprog_body
distinction ("ugly" hard-coded state):
real 0m46.058s
user 0m45.110s
sys 0m0.370s
So for kdevelop adasupport I'm going with the hard state rule
for subprograms.
Oliver Kellogg
next prev parent reply other threads:[~2003-02-11 1:24 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-02-08 9:02 GPS - A new kind of IDE? Oliver Kellogg
2003-02-08 10:30 ` Preben Randhol
2003-02-11 1:24 ` Oliver Kellogg [this message]
2003-02-15 22:08 ` Oliver Kellogg
-- strict thread matches above, loose matches on Subject: below --
2002-05-10 18:41 Alexandre E. Kopilovitch
[not found] <000001c1f762$aed14310$7201a8c0@bacus>
2002-05-09 14:15 ` Mário Amado Alves
2002-05-02 2:59 GNAT Programming System - Wow Steve Doiel
2002-05-05 19:35 ` Per Sandbergs
2002-05-06 9:58 ` Preben Randhol
2002-05-06 21:52 ` Robert Dewar
2002-05-07 10:11 ` Preben Randhol
2002-05-07 11:30 ` GPS - A new kind of IDE? John McCabe
2002-05-08 2:34 ` Robert Dewar
2002-05-08 7:49 ` Martin Dowie
2002-05-08 10:40 ` Preben Randhol
2002-05-08 8:17 ` John McCabe
2002-05-08 8:34 ` Martin Dowie
2002-05-08 10:57 ` Preben Randhol
2002-05-08 13:59 ` Wes Groleau
2002-05-09 14:06 ` Mário Amado Alves
2002-05-09 14:06 ` Mário Amado Alves
2002-05-10 2:22 ` Richard Riehle
2002-05-10 8:38 ` Preben Randhol
2002-05-10 10:39 ` Peter Hermann
2002-05-10 14:13 ` Stephen Leake
2002-05-10 14:52 ` David C. Hoos
2002-05-10 15:48 ` Marin David Condic
2002-05-11 12:39 ` Robert Dewar
2002-05-12 19:12 ` James Ross
2002-05-12 21:21 ` Preben Randhol
2002-05-10 15:46 ` Robert Dewar
2002-05-10 16:04 ` Mário Amado Alves
2002-05-11 0:44 ` Richard Riehle
2002-05-14 9:07 ` John McCabe
2002-05-14 13:00 ` Larry Kilgallen
2002-05-10 13:16 ` Robert Dewar
2002-05-10 13:19 ` Robert Dewar
2002-05-10 14:18 ` Stephen Leake
2002-05-10 15:18 ` Rajat Datta
2002-05-14 9:09 ` John McCabe
2002-05-14 14:16 ` Robert Dewar
2002-05-14 16:24 ` John McCabe
2002-05-14 15:22 ` Ted Dennison
2002-05-10 15:34 ` Arnaud Charlet
2002-05-10 16:32 ` Preben Randhol
2002-05-10 13:22 ` Marin David Condic
2002-05-13 14:56 ` Ted Dennison
2002-05-11 10:34 ` Florian Weimer
2002-05-11 10:34 ` Florian Weimer
2002-05-13 13:06 ` Georg Bauhaus
2002-05-14 15:31 ` Ted Dennison
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