"""Document handler classes for use in handling SGML documents.
"""
__version__ = "$Revision: 1.1 $"
# $Source: /projects/cvsroot/grail/dist/src/sgml/SGMLHandler.py,v $
import SGMLLexer
import SGMLParser
class ElementHandler:
def close(self):
pass
def get_taginfo(self, tag):
start = do = end = None
klass = self.__class__
if hasattr(klass, "start_" + tag):
start = getattr(klass, "start_" + tag)
if hasattr(klass, "end_" + tag):
end = getattr(klass, "end_" + tag)
elif hasattr(klass, "do_" + tag):
do = getattr(klass, "do_" + tag)
if start or do:
return SGMLParser.TagInfo(tag, start, do, end)
def handle_endtag(self, tag, method):
"""
"""
method(self)
def handle_starttag(self, tag, method, attributes):
"""
"""
method(self, attributes)
class BaseSGMLHandler(ElementHandler):
# The following methods are the interface subclasses need to
# override to support any special handling of tags, data, or
# anomalous conditions.
# Example -- handle entity reference, no need to override for most
# applications.
entitydefs = \
{'lt': '<', 'gt': '>', 'amp': '&', 'quot': '"'}
def handle_entityref(self, name, terminator):
"""
"""
table = self.entitydefs
if table.has_key(name):
self.handle_data(table[name])
else:
self.unknown_entityref(name, terminator)
def handle_data(self, data):
"""
"""
pass
def handle_sdata(self, data):
"""
"""
self.handle_data(data)
def handle_pi(self, pi_data):
pass
def unknown_charref(self, ordinal, terminator):
"""
"""
self.handle_data("%s%d%s" % (SGMLLexer.CRO, ordinal, terminator))
def unknown_endtag(self, tag):
"""
"""
pass
def unknown_entityref(self, ref, terminator):
"""
"""
self.handle_data("%s%s%s" % (SGMLLexer.ERO, ref, terminator))
def unknown_namedcharref(self, ref, terminator):
"""
"""
self.handle_data("%s%d%s" % (SGMLLexer.CRO, ordinal, terminator))
def unknown_starttag(self, tag, attrs):
"""
"""
pass
def report_unbalanced(self, tag):
"""
"""
pass
class CompositeHandler:
"""Compose two Handler-like classes into a composite form.
This is intended to allow a simple class to extend the element set
accepted by an instantiated gatherer without duplicating all the
fundamental operations of the primary gatherer. Both objects being
composed need to implement the get_taginfo() method; this may be
inherited from the ElementHandler class.
"""
def __init__(self, primary, secondary):
"""Compose two gatherers into a single gatherer.
primary
The 'base' gatherer; it is expected to provide most of the
implementation of the composite.
secondary
An extension to the base; it is expected to provide new tag
handlers or extend/replace handlers already on the primary
gatherer.
"""
self.doctype = primary.doctype
self.__primary = primary
self.__secondary = secondary
for attr in ("handle_data", "handle_sdata", "handle_entityref",
"unknown_entityref", "unknown_endtag",
"unknown_starttag", "unknown_namedcharref",
"report_unbalanced"):
if hasattr(secondary, attr):
setattr(self, attr, getattr(secondary, attr))
else:
setattr(self, attr, getattr(primary, attr))
self.__tagmap = {}
def close(self):
self.__secondary.close()
def get_taginfo(self, tag):
taginfo = self.__secondary.get_taginfo(tag)
if taginfo:
self.__tagmap[tag] = self.__secondary
else:
self.__tagmap[tag] = self.__primary
taginfo = self.__primary.get_taginfo(tag)
return taginfo
def handle_starttag(self, tag, method, attrs):
self.__tagmap[tag].handle_starttag(tag, method, attrs)
def handle_endtag(self, tag, method):
self.__tagmap[tag].handle_endtag(tag, method)
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