Path: utzoo!attcan!uunet!lll-winken!xanth!ames!mailrus!husc6!spdcc!ima!compilers-sender
From: heuring@BOULDER.COLORADO.EDU (Vincent Heuring)
Newsgroups: comp.compilers
Subject: Alternatives to Lex
Message-ID: <3291@ima.ima.isc.com>
Date: 6 Feb 89 21:45:45 GMT
Sender: compilers-sender@ima.ima.isc.com
Reply-To: heuring@BOULDER.COLORADO.EDU (Vincent Heuring)
Lines: 66
Approved: compilers@ima.UUCP

Dave Berry <lfcs.edinburgh.ac.uk!db@NSS.CS.UCL.AC.UK> Writes:

>The following references describe scanner generators that are claimed to
>produce smaller and faster scanners than Lex. ...
>
>@Article(gla,
>        Author="V. P. Heuring",
>        Title="The Automatic Generation of Fast Lexical Analysers",
>        Journal="Software Practice and Experience",
>        Volume="16", Number="9", Pages="801-808", Month="Sep", Year="1986")

So far as I know, GLA still generates the fastest scanners for
programming languages.[1]  With some 50 copies of GLA having been released,
We have had criticism that the input specification langugage
for GLA was inflexible.[2]  That has now been fixed.[3] GLA now
permits regular expressions, as well as having a library
of the more frequently used regular expressions.  This means that
the user may be able to generate a scanner without writing regular
expressions, but may do so if it is necessary.

GLA also comes with a library of 'processors' that permit hash-table
storage of internal forms of scanned identifiers, integers, etc.
The user may also escape to a custom written scanner, if necessary.

For a copy of the documentation, or a beta release of the new GLA
(it is presently known as gamma-GLA) mail to Bob Gray: bob@colorado.EDU.

I am presently writing up the details of our experience with GLA
for SP&E.

[1]
%A W. M. Waite
%T The Cost of Lexical Analysis
%P 473-488
%J SPE
%V 16
%N 5
%D MAY 1986

[2]
%A William M. Waite
%A Vincent P. Heuring
%A Robert W. Gray
%T GLA \(em A Generator for Lexical Analyzers
%P 17
%R User Manual
%I Department of Electrical and Computer Engineering, University of Colorado
%C Boulder, CO
%D APR 1986

[3]
%A Robert Gray
%T GLA - A Generator for Lexical Analyzers That Programmers Can Use
%J Proceedings of the Summer 1988 USENIX Conference
%C San Francisco
%D June 1988

| Vincent Heuring				|
| Dep't of Electrical & Computer Engineering	|
| University of Colorado - Boulder		|
| heuring@colorado.EDU				|
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