Class design for parser object

[James Saker]

I've been working on a Python class object for APRS (Automatic Position
Reporting System - a digital mode used by amateur radio operators) and have
been going through David Mertz's Text Processing in Python book to help in
the construction of the parser component of the class.

I was curious if there was a good reference on the most pythonic design of
parsing objects. For instance, should one parse raw or formatted data upon
initialization and return a boolean indicating success/failure, or require
multiple steps to instantiate then parse and test? Are there generally found
public methods in parsing objects that would serve as a good model?

Thanks -

Jamie