Added the make_parser function (patch 101571).

Lib/xml/sax/__init__.py

@@ -22,7 +22,6 @@ expatreader -- Driver that allows use of the Expat parser with the
 """
 
 from handler import ContentHandler, ErrorHandler
-from expatreader import ExpatParser
 from _exceptions import SAXException, SAXNotRecognizedException, \
                         SAXParseException, SAXNotSupportedException
 
@@ -33,7 +32,6 @@ def parse(filename_or_stream, handler, errorHandler=ErrorHandler()):
     parser.setErrorHandler(errorHandler)
     parser.parse(filename_or_stream)
 
-
 def parseString(string, handler, errorHandler=ErrorHandler()):
     try:
         from cStringIO import StringIO
@@ -46,3 +44,70 @@ def parseString(string, handler, errorHandler=ErrorHandler()):
     parser.setContentHandler(handler)
     parser.setErrorHandler(errorHandler)
     parser.parse(StringIO(string))
+
+# this is the parser list used by the make_parser function if no
+# alternatives are given as parameters to the function
+
+default_parser_list = ["xml.sax.expatreader"]
+
+import os, string, sys
+if os.environ.has_key("PY_SAX_PARSER"):
+    default_parser_list = string.split(os.environ["PY_SAX_PARSER"], ",")
+del os
+
+_key = "python.xml.sax.parser"
+if sys.platform[:4] == "java" and sys.registry.containsKey(_key):
+    default_parser_list = string.split(sys.registry.getProperty(_key), ",")
+    
+    
+def make_parser(parser_list = []):
+    """Creates and returns a SAX parser.
+
+    Creates the first parser it is able to instantiate of the ones
+    given in the list created by doing parser_list +
+    default_parser_list.  The lists must contain the names of Python
+    modules containing both a SAX parser and a create_parser function."""
+
+    for parser_name in parser_list + default_parser_list:
+        try:
+	    return _create_parser(parser_name)
+        except ImportError,e:
+            pass
+
+    raise SAXException("No parsers found", None)  
+    
+# --- Internal utility methods used by make_parser
+
+if sys.platform[ : 4] == "java":
+    def _create_parser(parser_name):
+    	from org.python.core import imp
+    	drv_module = imp.importName(parser_name, 0, globals())
+    	return drv_module.create_parser()
+
+else:
+    import imp as _imp
+    
+    def _rec_find_module(module):
+    	"Improvement over imp.find_module which finds submodules."
+    	path=""
+    	for mod in string.split(module,"."):
+            if path == "":
+            	info = (mod,) + _imp.find_module(mod)
+            else:
+            	info = (mod,) + _imp.find_module(mod, [path])
+            	
+            lastmod = apply(imp.load_module, info)
+    
+            try:
+            	path = lastmod.__path__[0]
+            except AttributeError, e:
+            	pass
+    
+    	return info
+    	
+    def _create_parser(parser_name):
+    	info = _rec_find_module(parser_name)
+    	drv_module = apply(imp.load_module, info)
+    	return drv_module.create_parser()
+
+del sys