From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: **
X-Spam-Status: No, score=2.2 required=5.0 tests=BAYES_00,FROM_WORDY,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,eb664162efb14c78
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2002-12-16 04:46:31 PST
Path: 
 archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!feed2.news.rcn.net!feed1.news.rcn.net!rcn!not-for-mail
From: "Frank J. Lhota" <NOSPAM.FrankLho@rcn.com>
Newsgroups: comp.lang.ada
Subject: Re: Why would it take so long to write an Ada compiler?
Date: Mon, 16 Dec 2002 07:46:25 -0500
Message-ID: <atkhtn$jkj$1@bob.news.rcn.net>
References: <MPG.1865cca835f2ccee98991a@News.CIS.DFN.DE>
 <8db3d6c8.0212151923.12bf6052@posting.google.com>
Reply-To: "Frank J. Lhota" <NOSPAM.FrankLho@rcn.com>
X-Trace: UmFuZG9tSVYwlFuI10Pu6bhjXYlFkJB2AjIDeIZkGX9e4k47CmD2FUMv6mQhmfSm
X-Complaints-To: abuse@rcn.com
NNTP-Posting-Date: 16 Dec 2002 12:45:43 GMT
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106
X-Priority: 3
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
X-MSMail-Priority: Normal
Xref: archiver1.google.com comp.lang.ada:31886
Date: 2002-12-16T12:45:43+00:00
List-Id: <comp.lang.ada>

"steve_H" <nma124@hotmail.com> wrote in message
news:8db3d6c8.0212151923.12bf6052@posting.google.com...
> Mike <spamnotme@invalid.com> wrote in message
news:<MPG.1865cca835f2ccee98991a@News.CIS.DFN.DE>...
> compilers are hard. code generation and optimization is the hardest
> part I would think. lex and yacc can do most of the front work. GNAT
> does not use lex and yacc.

A lot, possibly most, commercial compilers do not use lex and yacc. The
problem with yacc is the "bottom up" approach it takes to program parsing.
"Top Down" parsing makes it easier to generate good error messages.