[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: lex, yacc, and xml

• From: Richard Tobin <richard@c...>
• To: ht@c... (Henry S. Thompson), xml-dev@i...
• Date: Sat, 27 Dec 1997 18:11:12 GMT

> The currently available LT XML release (http://www.ltg.ed.ac.uk/software/xml/) 
> uses a lex/yacc parser.

The ugliest part of this code is the DTD parsing, because you want
(say) SYSTEM returned in some places as a keyword, and in others as a
name.  To achieve this, the yacc layer has to be constantly setting
the lexer mode ("lexical tie-ins").  Contrast this with C (surprise!)
where you can't have a variable with the same name as a keyword.

As Henry said, the performance is one reason why we switched to a plain
C parser.  Another is the question of 16-bit characters, though this
could probably have been kludged since all the syntactically important
characters are < 128.

-- Richard


xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i...
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/
To (un)subscribe, mailto:majordomo@i... the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo@i... the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa@i...)

• Prev by Date: RE: IDL?
• Next by Date: RE: IDL?
• Previous by thread: lex, yacc, and xml
• Next by thread: JFC and SGML
• Index(es):
  • Date
  • Thread