Merge pull request #1756 from leonelcamara/i1752

Make _compat accept ducks

gluon/_compat.py

@@ -63,7 +63,7 @@ if PY2:
             return None
         if isinstance(obj, (bytes, bytearray, buffer)):
             return bytes(obj)
-        if isinstance(obj, unicode):
+        if hasattr(obj, 'encode'):
             return obj.encode(charset, errors)
         raise TypeError('Expected bytes')
 
@@ -122,7 +122,7 @@ else:
             return None
         if isinstance(obj, (bytes, bytearray, memoryview)):
             return bytes(obj)
-        if isinstance(obj, str):
+        if hasattr(obj, 'encode'):
             return obj.encode(charset, errors)
         raise TypeError('Expected bytes')
 
@@ -151,7 +151,7 @@ def with_metaclass(meta, *bases):
 def to_unicode(obj, charset='utf-8', errors='strict'):
     if obj is None:
         return None
-    if not isinstance(obj, bytes):
+    if not hasattr(obj, 'decode'):
         return text_type(obj)
     return obj.decode(charset, errors)
 

gluon/languages.py

@@ -18,10 +18,11 @@ import pkgutil
 import logging
 from cgi import escape
 from threading import RLock
-from gluon.utf8 import Utf8
+
 from gluon.utils import local_html_escape
 
 from gluon._compat import copyreg, PY2, maketrans, iterkeys, unicodeT, to_unicode, to_bytes, iteritems, to_native, pjoin
+
 from pydal.contrib.portalocker import read_locked, LockedFile
 
 from gluon.fileutils import listdir
@@ -49,8 +50,10 @@ DEFAULT_CONSTRUCT_PLURAL_FORM = lambda word, plural_id: word
 
 if PY2:
     NUMBERS = (int, long, float)
+    from gluon.utf8 import Utf8
 else:
     NUMBERS = (int, float)
+    Utf8 = str
 
 # pattern to find T(blah blah blah) expressions
 PY_STRING_LITERAL_RE = r'(?<=[^\w]T\()(?P<name>'\