common/mllib/__init__.py

#
# Licensed to the Apache Software Foundation (ASF) under one
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# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
# 
#   http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
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"""
This module provides document parsing and transformation utilities for
both SGML and XML.
"""

import os, dom, transforms, parsers, sys
import xml.sax, types
from xml.sax.handler import ErrorHandler
from xml.sax.xmlreader import InputSource
from cStringIO import StringIO

def transform(node, *args):
  result = node
  for t in args:
    if isinstance(t, types.ClassType):
      t = t()
    result = result.dispatch(t)
  return result

def sgml_parse(source):
  if isinstance(source, basestring):
    source = StringIO(source)
    fname = "<string>"
  elif hasattr(source, "name"):
    fname = source.name
  p = parsers.SGMLParser()
  num = 1
  for line in source:
    p.feed(line)
    p.parser.line(fname, num, None)
    num += 1
  p.close()
  return p.parser.tree

class Resolver:

  def __init__(self, path):
    self.path = path

  def resolveEntity(self, publicId, systemId):
    for p in self.path:
      fname = os.path.join(p, systemId)
      if os.path.exists(fname):
        source = InputSource(systemId)
        source.setByteStream(open(fname))
        return source
    return InputSource(systemId)

def xml_parse(filename, path=()):
  if sys.version_info[0:2] == (2,3):
    # XXX: this is for older versions of python
    from urllib import pathname2url
    source = "file:%s" % pathname2url( os.path.abspath( filename ) )
  else:
    source = filename
  h = parsers.XMLParser()
  p = xml.sax.make_parser()
  p.setContentHandler(h)
  p.setErrorHandler(ErrorHandler())
  p.setEntityResolver(Resolver(path))
  p.parse(source)
  return h.parser.tree

def sexp(node):
  s = transforms.Sexp()
  node.dispatch(s)
  return s.out