From: Trans <transfire@...>
Date: 2005-01-28T01:31:00+09:00
Subject: Re: Duping a class causes error

Good point. Fortunately these classes are all self contained beyond
being subclasses of Marker.

The reason has to do with some trouble I alsways seem to run into with
these types of apps. Basically I have a Parser instance that gets fed
Token classes (Markers) which contain class level information on how to
recognize the relavent text they will parse. Here a very simple
example:

require 'yaml'

s = "[test]THIS IS A [b]TEST[b.]&tm;[test.]"

class XmlTagToken < Parser::Token
normal!
def self.start( match ) ; %r{ \[ (.*?) \] }mx ; end
def self.stop( match ) ; %r{ \[ [ ]* (#{Regexp.escape(match[1])})
(.*?) \. \] }mx ; end
end

class XmlEntityToken < Parser::Token
unit!
def self.start( match ) ; %r{ \& (.*?) \; }x ; end
end

registry = Parser::Registry.new
registry.register( XmlTagToken )
registry.register( XmlEntityToken )

cp = Parser.new( registry )
d = cp.parse( s )
y d

The I take this further and add instance methods to the tokens to parse
sepecialize content. Sometimes that content is "reentrant", that is to
say I need to reparse it --like an embedded document.

So the problem? How do I talk to my Parser instance from within an
instance of a Token?

If you have an elgant solution to that I'll give you more than a pat on
the back!

T.