WIP: Unify to a single code base compatible with both Python 2 & 3

MANIFEST.in

@@ -1,7 +1,5 @@
 include README LICENSE CHANGES setup.py
 recursive-include lib/yaml *.py
-recursive-include lib3/yaml *.py
 recursive-include examples *.py *.cfg *.yaml
 recursive-include tests/data *
 recursive-include tests/lib *.py
-recursive-include tests/lib3 *.py

lib/yaml/__init__.py

@@ -1,21 +1,24 @@
+from __future__ import unicode_literals
 
-from error import *
+import six
 
-from tokens import *
-from events import *
-from nodes import *
+from .error import *
 
-from loader import *
-from dumper import *
+from .tokens import *
+from .events import *
+from .nodes import *
 
-__version__ = '5.1b7'
+from .loader import *
+from .dumper import *
 
+__version__ = '5.1b7'
 try:
-    from cyaml import *
+    from .cyaml import *
     __with_libyaml__ = True
 except ImportError:
     __with_libyaml__ = False
 
+import io
 
 #------------------------------------------------------------------------------
 # Warnings control
@@ -200,8 +203,7 @@ def emit(events, stream=None, Dumper=Dumper,
     """
     getvalue = None
     if stream is None:
-        from StringIO import StringIO
-        stream = StringIO()
+        stream = io.StringIO()
         getvalue = stream.getvalue
     dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
             allow_unicode=allow_unicode, line_break=line_break)
@@ -216,7 +218,7 @@ def emit(events, stream=None, Dumper=Dumper,
 def serialize_all(nodes, stream=None, Dumper=Dumper,
         canonical=None, indent=None, width=None,
         allow_unicode=None, line_break=None,
-        encoding='utf-8', explicit_start=None, explicit_end=None,
+        encoding=None, explicit_start=None, explicit_end=None,
         version=None, tags=None):
     """
     Serialize a sequence of representation trees into a YAML stream.
@@ -225,10 +227,9 @@ def serialize_all(nodes, stream=None, Dumper=Dumper,
     getvalue = None
     if stream is None:
         if encoding is None:
-            from StringIO import StringIO
+            stream = io.StringIO()
         else:
-            from cStringIO import StringIO
-        stream = StringIO()
+            stream = io.BytesIO()
         getvalue = stream.getvalue
     dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
             allow_unicode=allow_unicode, line_break=line_break,
@@ -255,7 +256,7 @@ def dump_all(documents, stream=None, Dumper=Dumper,
         default_style=None, default_flow_style=False,
         canonical=None, indent=None, width=None,
         allow_unicode=None, line_break=None,
-        encoding='utf-8', explicit_start=None, explicit_end=None,
+        encoding=None, explicit_start=None, explicit_end=None,
         version=None, tags=None, sort_keys=True):
     """
     Serialize a sequence of Python objects into a YAML stream.
@@ -264,10 +265,9 @@ def dump_all(documents, stream=None, Dumper=Dumper,
     getvalue = None
     if stream is None:
         if encoding is None:
-            from StringIO import StringIO
+            stream = io.StringIO()
         else:
-            from cStringIO import StringIO
-        stream = StringIO()
+            stream = io.BytesIO()
         getvalue = stream.getvalue
     dumper = Dumper(stream, default_style=default_style,
             default_flow_style=default_flow_style,
@@ -374,13 +374,12 @@ def __init__(cls, name, bases, kwds):
             cls.yaml_loader.add_constructor(cls.yaml_tag, cls.from_yaml)
             cls.yaml_dumper.add_representer(cls, cls.to_yaml)
 
-class YAMLObject(object):
+class YAMLObject(six.with_metaclass(YAMLObjectMetaclass)):
     """
     An object that can dump itself to a YAML stream
     and load itself from a YAML stream.
     """
 
-    __metaclass__ = YAMLObjectMetaclass
     __slots__ = ()  # no direct instantiation, so allow immutable subclasses
 
     yaml_loader = Loader
@@ -389,18 +388,17 @@ class YAMLObject(object):
     yaml_tag = None
     yaml_flow_style = None
 
+    @classmethod
     def from_yaml(cls, loader, node):
         """
         Convert a representation node to a Python object.
         """
         return loader.construct_yaml_object(node, cls)
-    from_yaml = classmethod(from_yaml)
 
+    @classmethod
     def to_yaml(cls, dumper, data):
         """
         Convert a Python object to a representation node.
         """
         return dumper.represent_yaml_object(cls.yaml_tag, data, cls,
                 flow_style=cls.yaml_flow_style)
-    to_yaml = classmethod(to_yaml)
-

lib/yaml/composer.py

@@ -1,9 +1,10 @@
+from __future__ import unicode_literals
 
 __all__ = ['Composer', 'ComposerError']
 
-from error import MarkedYAMLError
-from events import *
-from nodes import *
+from .error import MarkedYAMLError
+from .events import *
+from .nodes import *
 
 class ComposerError(MarkedYAMLError):
     pass
@@ -66,14 +67,14 @@ def compose_node(self, parent, index):
             anchor = event.anchor
             if anchor not in self.anchors:
                 raise ComposerError(None, None, "found undefined alias %r"
-                        % anchor.encode('utf-8'), event.start_mark)
+                        % anchor, event.start_mark)
             return self.anchors[anchor]
         event = self.peek_event()
         anchor = event.anchor
         if anchor is not None:
             if anchor in self.anchors:
                 raise ComposerError("found duplicate anchor %r; first occurrence"
-                        % anchor.encode('utf-8'), self.anchors[anchor].start_mark,
+                        % anchor, self.anchors[anchor].start_mark,
                         "second occurrence", event.start_mark)
         self.descend_resolver(parent, index)
         if self.check_event(ScalarEvent):
@@ -88,7 +89,7 @@ def compose_node(self, parent, index):
     def compose_scalar_node(self, anchor):
         event = self.get_event()
         tag = event.tag
-        if tag is None or tag == u'!':
+        if tag is None or tag == '!':
             tag = self.resolve(ScalarNode, event.value, event.implicit)
         node = ScalarNode(tag, event.value,
                 event.start_mark, event.end_mark, style=event.style)
@@ -99,7 +100,7 @@ def compose_scalar_node(self, anchor):
     def compose_sequence_node(self, anchor):
         start_event = self.get_event()
         tag = start_event.tag
-        if tag is None or tag == u'!':
+        if tag is None or tag == '!':
             tag = self.resolve(SequenceNode, None, start_event.implicit)
         node = SequenceNode(tag, [],
                 start_event.start_mark, None,
@@ -117,7 +118,7 @@ def compose_sequence_node(self, anchor):
     def compose_mapping_node(self, anchor):
         start_event = self.get_event()
         tag = start_event.tag
-        if tag is None or tag == u'!':
+        if tag is None or tag == '!':
             tag = self.resolve(MappingNode, None, start_event.implicit)
         node = MappingNode(tag, [],
                 start_event.start_mark, None,
@@ -136,4 +137,3 @@ def compose_mapping_node(self, anchor):
         end_event = self.get_event()
         node.end_mark = end_event.end_mark
         return node
-