Python dual support (#266)

* WIP

* Metaclasses

* String literal fixes

* Remove 2to3 and make tests compatible with both Python 2 & 3

* Removed debug code.

* Added tests for ProgressBar

* Fixed examples.

* future division & font literals fix

* Cleaner fonts initialization.

34 files changed, 285 insertions, 153 deletions

diff --git a/examples/twisted_serve_ssh.py b/examples/twisted_serve_ssh.py
index 5335646..c1a0004 100644
--- a/examples/twisted_serve_ssh.py
+++ b/examples/twisted_serve_ssh.py
@@ -200,7 +200,7 @@ class TwistedScreen(Screen):
         """
         return self.terminalProtocol.width, self.terminalProtocol.height
 
-    def draw_screen(self, (maxcol, maxrow), r ):
+    def draw_screen(self, maxres, r ):
         """Render a canvas to the terminal.
 
         The canvas contains all the information required to render the Urwid
@@ -208,6 +208,7 @@ class TwistedScreen(Screen):
         tuples. This very simple implementation iterates each row and simply
         writes it out.
         """
+        (maxcol, maxrow) = maxres
         #self.terminal.eraseDisplay()
         lasta = None
         for i, row in enumerate(r.content()):
@@ -411,9 +412,10 @@ class UrwidTerminalSession(TerminalSession):
             IConchUser(self.original),
             self.height, self.width)
 
-    def windowChanged(self, (h, w, x, y)):
+    def windowChanged(self, dimensions):
         """Called when the window size has changed.
         """
+        (h, w, x, y) = dimensions
         self.chained_protocol.terminalProtocol.terminalSize(h, w)
 
 
diff --git a/setup.py b/setup.py
index fcb9e5f..37a7413 100644
--- a/setup.py
+++ b/setup.py
@@ -79,9 +79,6 @@ if have_setuptools:
     setup_d['zip_safe'] = False
     setup_d['test_suite'] = 'urwid.tests'
 
-if PYTHON3:
-    setup_d['use_2to3'] = True
-
 if __name__ == "__main__":
     try:
         setup(**setup_d)
diff --git a/urwid/__init__.py b/urwid/__init__.py
index bc5170e..32484de 100644
--- a/urwid/__init__.py
+++ b/urwid/__init__.py
@@ -20,6 +20,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from urwid.version import VERSION, __version__
 from urwid.widget import (FLOW, BOX, FIXED, LEFT, RIGHT, CENTER, TOP, MIDDLE,
     BOTTOM, SPACE, ANY, CLIP, PACK, GIVEN, RELATIVE, RELATIVE_100, WEIGHT,
diff --git a/urwid/canvas.py b/urwid/canvas.py
index 4a51d3e..207ee21 100644
--- a/urwid/canvas.py
+++ b/urwid/canvas.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 import weakref
 
 from urwid.util import rle_len, rle_append_modify, rle_join_modify, rle_product, \
@@ -828,7 +830,7 @@ def shard_body_row(sbody):
     row = []
     for done_rows, content_iter, cview in sbody:
         if content_iter:
-            row.extend(content_iter.next())
+            row.extend(next(content_iter))
         else:
             # need to skip this unchanged canvas
             if row and type(row[-1]) == int:
@@ -867,10 +869,10 @@ def shards_delta(shards, other_shards):
     done = other_done = 0
     for num_rows, cviews in shards:
         if other_num_rows is None:
-            other_num_rows, other_cviews = other_shards_iter.next()
+            other_num_rows, other_cviews = next(other_shards_iter)
         while other_done < done:
             other_done += other_num_rows
-            other_num_rows, other_cviews = other_shards_iter.next()
+            other_num_rows, other_cviews = next(other_shards_iter)
         if other_done > done:
             yield (num_rows, cviews)
             done += num_rows
@@ -889,10 +891,10 @@ def shard_cviews_delta(cviews, other_cviews):
     cols = other_cols = 0
     for cv in cviews:
         if other_cv is None:
-            other_cv = other_cviews_iter.next()
+            other_cv = next(other_cviews_iter)
         while other_cols < cols:
             other_cols += other_cv[2]
-            other_cv = other_cviews_iter.next()
+            other_cv = next(other_cviews_iter)
         if other_cols > cols:
             yield cv
             cols += cv[2]
@@ -926,7 +928,7 @@ def shard_body(cviews, shard_tail, create_iter=True, iter_default=None):
     for col_gap, done_rows, content_iter, tail_cview in shard_tail:
         while col_gap:
             try:
-                cview = cviews_iter.next()
+                cview = next(cviews_iter)
             except StopIteration:
                 raise CanvasError("cviews do not fill gaps in"
                     " shard_tail!")
@@ -1057,7 +1059,7 @@ def shards_join(shard_lists):
     All shards lists must have the same number of rows.
     """
     shards_iters = [iter(sl) for sl in shard_lists]
-    shards_current = [i.next() for i in shards_iters]
+    shards_current = [next(i) for i in shards_iters]
 
     new_shards = []
     while True:
@@ -1078,7 +1080,7 @@ def shards_join(shard_lists):
             for i in range(len(shards_current)):
                 if shards_current[i][0] > 0:
                     continue
-                shards_current[i] = shards_iters[i].next()
+                shards_current[i] = next(shards_iters[i])
         except StopIteration:
             break
     return new_shards
diff --git a/urwid/command_map.py b/urwid/command_map.py
index 15633f8..e6965f7 100644
--- a/urwid/command_map.py
+++ b/urwid/command_map.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 REDRAW_SCREEN = 'redraw screen'
 CURSOR_UP = 'cursor up'
 CURSOR_DOWN = 'cursor down'
diff --git a/urwid/compat.py b/urwid/compat.py
index 686d703..de0bf7a 100644
--- a/urwid/compat.py
+++ b/urwid/compat.py
@@ -20,6 +20,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 import sys
 
 try: # python 2.4 and 2.5 compat
@@ -39,10 +41,34 @@ if PYTHON3:
     chr2 = lambda x: bytes([x])
     B = lambda x: x.encode('iso8859-1')
     bytes3 = bytes
+    text_type = str
+    xrange = range
+    text_types = (str,)
 else:
     ord2 = ord
     chr2 = chr
     B = lambda x: x
     bytes3 = lambda x: bytes().join([chr(c) for c in x])
+    text_type = unicode
+    xrange = xrange
+    text_types = (str, unicode)
+
+
+def with_metaclass(meta, *bases):
+    """
+    Create a base class with a metaclass.
+    Taken from "six" library (https://pythonhosted.org/six/).
+    """
+    # This requires a bit of explanation: the basic idea is to make a dummy
+    # metaclass for one level of class instantiation that replaces itself with
+    # the actual metaclass.
+    class metaclass(type):
+
+        def __new__(cls, name, this_bases, d):
+            return meta(name, bases, d)
 
+        @classmethod
+        def __prepare__(cls, name, this_bases):
+            return meta.__prepare__(name, bases)
+    return type.__new__(metaclass, 'temporary_class', (), {})
 
diff --git a/urwid/container.py b/urwid/container.py
index 0483482..c2cc71f 100755
--- a/urwid/container.py
+++ b/urwid/container.py
@@ -19,7 +19,10 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from itertools import chain, repeat
+from urwid.compat import xrange
 
 from urwid.util import is_mouse_press
 from urwid.widget import (Widget, Divider, FLOW, FIXED, PACK, BOX, WidgetWrap,
@@ -1589,9 +1592,9 @@ class Pile(Widget, WidgetContainerMixin, WidgetContainerListContentsMixin):
                 return key
 
         if self._command_map[key] == 'cursor up':
-            candidates = range(i-1, -1, -1) # count backwards to 0
+            candidates = list(range(i-1, -1, -1)) # count backwards to 0
         else: # self._command_map[key] == 'cursor down'
-            candidates = range(i+1, len(self.contents))
+            candidates = list(range(i+1, len(self.contents)))
 
         if not item_rows:
             item_rows = self.get_item_rows(size, focus=True)
@@ -1607,9 +1610,9 @@ class Pile(Widget, WidgetContainerMixin, WidgetContainerListContentsMixin):
 
             rows = item_rows[j]
             if self._command_map[key] == 'cursor up':
-                rowlist = range(rows-1, -1, -1)
+                rowlist = list(range(rows-1, -1, -1))
             else: # self._command_map[key] == 'cursor down'
-                rowlist = range(rows)
+                rowlist = list(range(rows))
             for row in rowlist:
                 tsize = self.get_item_size(size, j, True, item_rows)
                 if self.focus_item.move_cursor_to_coords(
@@ -2272,9 +2275,9 @@ class Columns(Widget, WidgetContainerMixin, WidgetContainerListContentsMixin):
             return key
 
         if self._command_map[key] == 'cursor left':
-            candidates = range(i-1, -1, -1) # count backwards to 0
+            candidates = list(range(i-1, -1, -1)) # count backwards to 0
         else: # key == 'right'
-            candidates = range(i+1, len(self.contents))
+            candidates = list(range(i+1, len(self.contents)))
 
         for j in candidates:
             if not self.contents[j][0].selectable():
diff --git a/urwid/curses_display.py b/urwid/curses_display.py
index 441042e..0aaa2f1 100755
--- a/urwid/curses_display.py
+++ b/urwid/curses_display.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 """
 Curses-based UI implementation
 """
@@ -30,7 +32,7 @@ from urwid import escape
 
 from urwid.display_common import BaseScreen, RealTerminal, AttrSpec, \
     UNPRINTABLE_TRANS_TABLE
-from urwid.compat import bytes, PYTHON3
+from urwid.compat import bytes, PYTHON3, text_type, xrange
 
 KEY_RESIZE = 410 # curses.KEY_RESIZE (sometimes not defined)
 KEY_MOUSE = 409 # curses.KEY_MOUSE
@@ -481,10 +483,12 @@ class Screen(BaseScreen, RealTerminal):
 
         self.s.attrset(attr)
 
-    def draw_screen(self, (cols, rows), r ):
+    def draw_screen(self, size, r ):
         """Paint screen with rendered canvas."""
         assert self._started
 
+        cols, rows = size
+
         assert r.rows() == rows, "canvas size and passed size don't match"
 
         y = -1
@@ -558,7 +562,7 @@ class Screen(BaseScreen, RealTerminal):
 class _test:
     def __init__(self):
         self.ui = Screen()
-        self.l = _curses_colours.keys()
+        self.l = list(_curses_colours.keys())
         self.l.sort()
         for c in self.l:
             self.ui.register_palette( [
@@ -602,7 +606,7 @@ class _test:
             t = ""
             a = []
             for k in keys:
-                if type(k) == unicode: k = k.encode("utf-8")
+                if type(k) == text_type: k = k.encode("utf-8")
                 t += "'"+k + "' "
                 a += [(None,1), ('yellow on dark blue',len(k)),
                     (None,2)]
diff --git a/urwid/decoration.py b/urwid/decoration.py
index 731eb91..978722f 100755
--- a/urwid/decoration.py
+++ b/urwid/decoration.py
@@ -19,6 +19,7 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
 
 from urwid.util import int_scale
 from urwid.widget import (Widget, WidgetError,
@@ -129,14 +130,14 @@ class AttrMap(delegate_to_widget_mixin('_original_widget'), WidgetDecoration):
         <AttrMap selectable flow widget <Edit selectable flow widget '' edit_pos=0> attr_map={None: 'notfocus'} focus_map={None: 'focus'}>
         >>> size = (5,)
         >>> am = AttrMap(Text(u"hi"), 'greeting', 'fgreet')
-        >>> am.render(size, focus=False).content().next() # ... = b in Python 3
+        >>> next(am.render(size, focus=False).content()) # ... = b in Python 3
         [('greeting', None, ...'hi   ')]
-        >>> am.render(size, focus=True).content().next()
+        >>> next(am.render(size, focus=True).content())
         [('fgreet', None, ...'hi   ')]
         >>> am2 = AttrMap(Text(('word', u"hi")), {'word':'greeting', None:'bg'})
         >>> am2
         <AttrMap flow widget <Text flow widget 'hi'> attr_map={'word': 'greeting', None: 'bg'}>
-        >>> am2.render(size).content().next()
+        >>> next(am2.render(size).content())
         [('greeting', None, ...'hi'), ('bg', None, ...'   ')]
         """
         self.__super.__init__(w)
@@ -247,9 +248,9 @@ class AttrWrap(AttrMap):
         <AttrWrap selectable flow widget <Edit selectable flow widget '' edit_pos=0> attr='notfocus' focus_attr='focus'>
         >>> size = (5,)
         >>> aw = AttrWrap(Text(u"hi"), 'greeting', 'fgreet')
-        >>> aw.render(size, focus=False).content().next()
+        >>> next(aw.render(size, focus=False).content())
         [('greeting', None, ...'hi   ')]
-        >>> aw.render(size, focus=True).content().next()
+        >>> next(aw.render(size, focus=True).content())
         [('fgreet', None, ...'hi   ')]
         """
         self.__super.__init__(w, attr, focus_attr)
@@ -460,7 +461,7 @@ class Padding(WidgetDecoration):
         >>> size = (7,)
         >>> def pr(w):
         ...     for t in w.render(size).text:
-        ...         print "|%s|" % (t.decode('ascii'),)
+        ...         print("|%s|" % (t.decode('ascii'),))
         >>> pr(Padding(Text(u"Head"), ('relative', 20), 'pack'))
         | Head  |
         >>> pr(Padding(Divider(u"-"), left=2, right=1))
diff --git a/urwid/display_common.py b/urwid/display_common.py
index 26f3a5a..e447682 100755
--- a/urwid/display_common.py
+++ b/urwid/display_common.py
@@ -18,6 +18,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 import os
 import sys
 
@@ -28,10 +30,10 @@ except ImportError:
 
 from urwid.util import StoppingContext, int_scale
 from urwid import signals
-from urwid.compat import B, bytes3
+from urwid.compat import B, bytes3, xrange, with_metaclass
 
 # for replacing unprintable bytes with '?'
-UNPRINTABLE_TRANS_TABLE = B("?") * 32 + bytes3(range(32,256))
+UNPRINTABLE_TRANS_TABLE = B("?") * 32 + bytes3(list(xrange(32,256)))
 
 
 # signals sent by BaseScreen
@@ -719,11 +721,10 @@ class RealTerminal(object):
 class ScreenError(Exception):
     pass
 
-class BaseScreen(object):
+class BaseScreen(with_metaclass(signals.MetaSignals, object)):
     """
     Base class for Screen classes (raw_display.Screen, .. etc)
     """
-    __metaclass__ = signals.MetaSignals
     signals = [UPDATE_PALETTE_ENTRY, INPUT_DESCRIPTORS_CHANGED]
 
     def __init__(self):
diff --git a/urwid/escape.py b/urwid/escape.py
index 683466c..b047fb0 100644
--- a/urwid/escape.py
+++ b/urwid/escape.py
@@ -20,6 +20,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 """
 Terminal Escape Sequences for input and display
 """
diff --git a/urwid/font.py b/urwid/font.py
index bf0c2b1..e7bfe6e 100755
--- a/urwid/font.py
+++ b/urwid/font.py
@@ -20,9 +20,12 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from urwid.escape import SAFE_ASCII_DEC_SPECIAL_RE
 from urwid.util import apply_target_encoding, str_util
 from urwid.canvas import TextCanvas
+from urwid.compat import text_type
 
 
 def separate_glyphs(gdata, height):
@@ -96,9 +99,16 @@ class Font(object):
         self.char = {}
         self.canvas = {}
         self.utf8_required = False
-        for gdata in self.data:
+        data = [self._to_text(block) for block in self.data]
+        for gdata in data:
             self.add_glyphs(gdata)
 
+    @staticmethod
+    def _to_text(obj, encoding='utf-8', errors='strict'):
+        if isinstance(obj, text_type):
+            return obj
+        elif isinstance(obj, bytes):
+            return obj.decode(encoding, errors)
 
     def add_glyphs(self, gdata):
         d, utf8_required = separate_glyphs(gdata, self.height)
@@ -106,7 +116,7 @@ class Font(object):
         self.utf8_required |= utf8_required
 
     def characters(self):
-        l = self.char.keys()
+        l = list(self.char.keys())
         l.sort()
         return "".join(l)
 
@@ -147,7 +157,7 @@ class Thin3x3Font(Font):
 ┌─┐ ┐ ┌─┐┌─┐  ┐┌─ ┌─ ┌─┐┌─┐┌─┐  │
 │ │ │ ┌─┘ ─┤└─┼└─┐├─┐  ┼├─┤└─┤  │
 └─┘ ┴ └─ └─┘  ┴ ─┘└─┘  ┴└─┘ ─┘  .
-""", ur"""
+""", r"""
 "###$$$%%%'*++,--.///:;==???[[\\\]]^__`
 " ┼┼┌┼┐O /'         /.. _┌─┐┌ \   ┐^  `
   ┼┼└┼┐ /  * ┼  ─  / ., _ ┌┘│  \  │
@@ -179,7 +189,7 @@ class HalfBlock5x4Font(Font):
    ▀█▀█▀ ▀▄█▄    █  ▀▄▀  ▐▌ ▐▌ ▄▄█▄▄ ▄▄█▄▄    ▄▄▄▄    █  ▀  ▀
    ▀█▀█▀ ▄ █ █  ▐▌▄ █ ▀▄▌▐▌ ▐▌  ▄▀▄    █             ▐▌  ▀ ▄▀
     ▀ ▀   ▀▀▀   ▀ ▀  ▀▀   ▀ ▀              ▄▀      ▀ ▀
-''', ur"""
+''', r"""
 <<<<<=====>>>>>?????@@@@@@[[[[\\\\]]]]^^^^____```{{{{||}}}}~~~~''´´´
   ▄▀      ▀▄   ▄▀▀▄ ▄▀▀▀▄ █▀▀ ▐▌  ▀▀█ ▄▀▄     ▀▄  ▄▀ █ ▀▄   ▄  █ ▄▀
 ▄▀   ▀▀▀▀   ▀▄   ▄▀ █ █▀█ █    █    █            ▄▀  █  ▀▄ ▐▐▌▌
@@ -258,7 +268,7 @@ class Thin6x6Font(Font):
 │   │   │   │         │    │      │ │   │     │ │   │     │
 └───┘   ┴   └───  └───┘    ┴   ───┘ └───┘     ┴ └───┘  ───┘
 
-""", ur'''
+""", r'''
 !!   """######$$$$$$%%%%%%&&&&&&((()))******++++++
 │    ││  ┌ ┌  ┌─┼─┐ ┌┐  /  ┌─┐   / \
 │       ─┼─┼─ │ │   └┘ /   │ │  │   │  \ /    │
@@ -266,7 +276,7 @@ class Thin6x6Font(Font):
 │       ─┼─┼─   │ │  / ┌┐ │  \, │   │  / \    │
 .        ┘ ┘  └─┼─┘ /  └┘ └───\  \ /
 
-''', ur"""
+''', r"""
 ,,-----..//////::;;<<<<=====>>>>??????@@@@@@
              /                  ┌───┐ ┌───┐
             /  . .   / ──── \       │ │┌──┤
@@ -274,7 +284,7 @@ class Thin6x6Font(Font):
           /    . ,  \  ────  /    │   │└──┘
 ,      . /           \      /     .   └───┘
 
-""", ur"""
+""", r"""
 [[\\\\\\]]^^^____``{{||}}~~~~~~
 ┌ \     ┐ /\     \ ┌ │ ┐
 │  \    │          │ │ │ ┌─┐
@@ -363,7 +373,7 @@ class HalfBlock7x7Font(Font):
              █▌     ▀      ▀█▌      ▐█▀           ▐█ ▀▀▀
 ▐█       ▐█ ▐█                                █▌   ▀███▀
 ▀
-""", ur"""
+""", r"""
 [[[[\\\\\]]]]^^^^^^^_____```{{{{{|||}}}}}~~~~~~~´´´
 ▐██▌▐█   ▐██▌  ▐█▌       ▐█    █▌▐█ ▐█           █▌
 ▐█   █▌    █▌ ▐█ █▌       █▌  █▌ ▐█  ▐█   ▄▄    ▐█
@@ -433,18 +443,18 @@ add_font("Half Block 7x7",HalfBlock7x7Font)
 if __name__ == "__main__":
     l = get_all_fonts()
     all_ascii = "".join([chr(x) for x in range(32, 127)])
-    print "Available Fonts:     (U) = UTF-8 required"
-    print "----------------"
+    print("Available Fonts:     (U) = UTF-8 required")
+    print("----------------")
     for n,cls in l:
         f = cls()
         u = ""
         if f.utf8_required:
             u = "(U)"
-        print ("%-20s %3s " % (n,u)),
+        print(("%-20s %3s " % (n,u)), end=' ')
         c = f.characters()
         if c == all_ascii:
-            print "Full ASCII"
+            print("Full ASCII")
         elif c.startswith(all_ascii):
-            print "Full ASCII + " + c[len(all_ascii):]
+            print("Full ASCII + " + c[len(all_ascii):])
         else:
-            print "Characters: " + c
+            print("Characters: " + c)
diff --git a/urwid/graphics.py b/urwid/graphics.py
index cb852b0..a40f1ba 100755
--- a/urwid/graphics.py
+++ b/urwid/graphics.py
@@ -20,6 +20,9 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
+from urwid.compat import with_metaclass
 from urwid.util import decompose_tagmarkup, get_encoding_mode
 from urwid.canvas import CompositeCanvas, CanvasJoin, TextCanvas, \
     CanvasCombine, SolidCanvas
@@ -192,9 +195,7 @@ def nocache_bargraph_get_data(self, get_data_fn):
 class BarGraphError(Exception):
     pass
 
-class BarGraph(Widget):
-    __metaclass__ = BarGraphMeta
-
+class BarGraph(with_metaclass(BarGraphMeta, Widget)):
     _sizing = frozenset([BOX])
 
     ignore_focus = True
@@ -481,7 +482,8 @@ class BarGraph(Widget):
         o = []
         r = 0  # row remainder
 
-        def seg_combine((bt1, w1), (bt2, w2)):
+        def seg_combine(a, b):
+            (bt1, w1), (bt2, w2) = a, b
             if (bt1, w1) == (bt2, w2):
                 return (bt1, w1), None, None
             wmin = min(w1, w2)
@@ -811,6 +813,28 @@ class ProgressBar(Widget):
                      foreground of satt corresponds to the normal part and the
                      background corresponds to the complete part.  If satt
                      is ``None`` then no smoothing will be done.
+
+        >>> pb = ProgressBar('a', 'b')
+        >>> pb
+        <ProgressBar flow widget>
+        >>> print(pb.get_text())
+        0 %
+        >>> pb.set_completion(34.42)
+        >>> print(pb.get_text())
+        34 %
+        >>> class CustomProgressBar(ProgressBar):
+        ...     def get_text(self):
+        ...         return u'Foobar'
+        >>> cpb = CustomProgressBar('a', 'b')
+        >>> print(cpb.get_text())
+        Foobar
+        >>> for x in range(101):
+        ...     cpb.set_completion(x)
+        ...     s = cpb.render((10, ))
+        >>> cpb2 = CustomProgressBar('a', 'b', satt='c')
+        >>> for x in range(101):
+        ...     cpb2.set_completion(x)
+        ...     s = cpb2.render((10, ))
         """
         self.normal = normal
         self.complete = complete
@@ -915,3 +939,10 @@ class PythonLogo(Widget):
         """
         fixed_size(size)
         return self._canvas
+
+def _test():
+    import doctest
+    doctest.testmod()
+
+if __name__=='__main__':
+    _test()
diff --git a/urwid/highlight.css b/urwid/highlight.css
new file mode 100644
index 0000000..097663d
--- /dev/null
+++ b/urwid/highlight.css
@@ -0,0 +1,19 @@
+/* Style definition file generated by highlight 3.41, http://www.andre-simon.de/ */
+/* highlight theme: Kwrite Editor */
+body.hl	{ background-color:#e0eaee; }
+pre.hl	{ color:#000000; background-color:#e0eaee; font-size:10pt; font-family:'Courier New',monospace;}
+.hl.num { color:#b07e00; }
+.hl.esc { color:#ff00ff; }
+.hl.str { color:#bf0303; }
+.hl.pps { color:#818100; }
+.hl.slc { color:#838183; font-style:italic; }
+.hl.com { color:#838183; font-style:italic; }
+.hl.ppc { color:#008200; }
+.hl.opt { color:#000000; }
+.hl.ipl { color:#0057ae; }
+.hl.lin { color:#555555; }
+.hl.kwa { color:#000000; font-weight:bold; }
+.hl.kwb { color:#0057ae; }
+.hl.kwc { color:#000000; font-weight:bold; }
+.hl.kwd { color:#010181; }
+
diff --git a/urwid/html_fragment.py b/urwid/html_fragment.py
index 3db1fd9..5df9273 100755
--- a/urwid/html_fragment.py
+++ b/urwid/html_fragment.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 """
 HTML PRE-based UI implementation
 """
@@ -76,13 +78,15 @@ class HtmlGenerator(BaseScreen):
     def reset_default_terminal_palette(self, *args):
         pass
 
-    def draw_screen(self, (cols, rows), r ):
+    def draw_screen(self, size, r ):
         """Create an html fragment from the render object.
         Append it to HtmlGenerator.fragments list.
         """
         # collect output in l
         l = []
 
+        cols, rows = size
+
         assert r.rows() == rows
 
         if r.cursor is not None:
@@ -134,7 +138,7 @@ class HtmlGenerator(BaseScreen):
     def get_cols_rows(self):
         """Return the next screen size in HtmlGenerator.sizes."""
         if not self.sizes:
-            raise HtmlGeneratorSimulationError, "Ran out of screen sizes to return!"
+            raise HtmlGeneratorSimulationError("Ran out of screen sizes to return!")
         return self.sizes.pop(0)
 
     def get_input(self, raw_keys=False):
@@ -219,7 +223,7 @@ def screenshot_init( sizes, keys ):
             assert type(row) == int
             assert row>0 and col>0
     except (AssertionError, ValueError):
-        raise Exception, "sizes must be in the form [ (col1,row1), (col2,row2), ...]"
+        raise Exception("sizes must be in the form [ (col1,row1), (col2,row2), ...]")
 
     try:
         for l in keys:
@@ -227,11 +231,11 @@ def screenshot_init( sizes, keys ):
             for k in l:
                 assert type(k) == str
     except (AssertionError, ValueError):
-        raise Exception, "keys must be in the form [ [keyA1, keyA2, ..], [keyB1, ..], ...]"
+        raise Exception("keys must be in the form [ [keyA1, keyA2, ..], [keyB1, ..], ...]")
 
-    import curses_display
+    from . import curses_display
     curses_display.Screen = HtmlGenerator
-    import raw_display
+    from . import raw_display
     raw_display.Screen = HtmlGenerator
 
     HtmlGenerator.sizes = sizes
diff --git a/urwid/lcd_display.py b/urwid/lcd_display.py
index 4f62173..e189d9a 100644
--- a/urwid/lcd_display.py
+++ b/urwid/lcd_display.py
@@ -20,8 +20,9 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
 
-from display_common import BaseScreen
+from .display_common import BaseScreen
 
 import time
 
@@ -39,7 +40,7 @@ class LCDScreen(BaseScreen):
     def reset_default_terminal_palette(self, *args):
         pass
 
-    def draw_screen(self, (cols, rows), r ):
+    def draw_screen(self, size, r ):
         pass
 
     def clear(self):
diff --git a/urwid/listbox.py b/urwid/listbox.py
index 0a65afa..802b1d6 100644
--- a/urwid/listbox.py
+++ b/urwid/listbox.py
@@ -19,6 +19,9 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
+from urwid.compat import xrange, with_metaclass
 from urwid.util import is_mouse_press
 from urwid.canvas import SolidCanvas, CanvasCombine
 from urwid.widget import Widget, nocache_widget_render_instance, BOX, GIVEN
@@ -33,9 +36,7 @@ from urwid.command_map import (CURSOR_UP, CURSOR_DOWN,
 class ListWalkerError(Exception):
     pass
 
-class ListWalker(object):
-    __metaclass__ = signals.MetaSignals
-
+class ListWalker(with_metaclass(signals.MetaSignals, object)):
     signals = ["modified"]
 
     def _modified(self):
@@ -141,7 +142,7 @@ class SimpleListWalker(MonitoredList, ListWalker):
         this list walker to be updated.
         """
         if not getattr(contents, '__getitem__', None):
-            raise ListWalkerError, "SimpleListWalker expecting list like object, got: %r"%(contents,)
+            raise ListWalkerError("SimpleListWalker expecting list like object, got: %r"%(contents,))
         MonitoredList.__init__(self, contents)
         self.focus = 0
 
@@ -175,7 +176,7 @@ class SimpleListWalker(MonitoredList, ListWalker):
             if position < 0 or position >= len(self):
                 raise ValueError
         except (TypeError, ValueError):
-            raise IndexError, "No widget at position %s" % (position,)
+            raise IndexError("No widget at position %s" % (position,))
         self.focus = position
         self._modified()
 
@@ -481,17 +482,17 @@ class ListBox(Widget, WidgetContainerMixin):
         for widget,w_pos,w_rows in fill_above:
             canvas = widget.render((maxcol,))
             if w_rows != canvas.rows():
-                raise ListBoxError, "Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (widget,w_pos,w_rows, canvas.rows())
+                raise ListBoxError("Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (widget,w_pos,w_rows, canvas.rows()))
             rows += w_rows
             combinelist.append((canvas, w_pos, False))
 
         focus_canvas = focus_widget.render((maxcol,), focus=focus)
 
         if focus_canvas.rows() != focus_rows:
-            raise ListBoxError, "Focus Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (focus_widget,focus_pos,focus_rows, focus_canvas.rows())
+            raise ListBoxError("Focus Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (focus_widget,focus_pos,focus_rows, focus_canvas.rows()))
         c_cursor = focus_canvas.cursor
         if cursor != c_cursor:
-            raise ListBoxError, "Focus Widget %r at position %r within listbox calculated cursor coords %r but rendered cursor coords %r!" %(focus_widget,focus_pos,cursor,c_cursor)
+            raise ListBoxError("Focus Widget %r at position %r within listbox calculated cursor coords %r but rendered cursor coords %r!" %(focus_widget,focus_pos,cursor,c_cursor))
 
         rows += focus_rows
         combinelist.append((focus_canvas, focus_pos, True))
@@ -499,7 +500,7 @@ class ListBox(Widget, WidgetContainerMixin):
         for widget,w_pos,w_rows in fill_below:
             canvas = widget.render((maxcol,))
             if w_rows != canvas.rows():
-                raise ListBoxError, "Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (widget,w_pos,w_rows, canvas.rows())
+                raise ListBoxError("Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (widget,w_pos,w_rows, canvas.rows()))
             rows += w_rows
             combinelist.append((canvas, w_pos, False))
 
@@ -513,13 +514,13 @@ class ListBox(Widget, WidgetContainerMixin):
             rows -= trim_bottom
 
         if rows > maxrow:
-            raise ListBoxError, "Listbox contents too long!  Probably urwid's fault (please report): %r" % ((top,middle,bottom),)
+            raise ListBoxError("Listbox contents too long!  Probably urwid's fault (please report): %r" % ((top,middle,bottom),))
 
         if rows < maxrow:
             bottom_pos = focus_pos
             if fill_below: bottom_pos = fill_below[-1][1]
             if trim_bottom != 0 or self._body.get_next(bottom_pos) != (None,None):
-                raise ListBoxError, "Listbox contents too short!  Probably urwid's fault (please report): %r" % ((top,middle,bottom),)
+                raise ListBoxError("Listbox contents too short!  Probably urwid's fault (please report): %r" % ((top,middle,bottom),))
             final_canvas.pad_trim_top_bottom(0, maxrow - rows)
 
         return final_canvas
@@ -603,7 +604,7 @@ class ListBox(Widget, WidgetContainerMixin):
         """
         w, pos = self._body.get_focus()
         if w is None:
-            raise IndexError, "No focus_position, ListBox is empty"
+            raise IndexError("No focus_position, ListBox is empty")
         return pos
     focus_position = property(_get_focus_position, set_focus, doc="""
         the position of child widget in focus. The valid values for this
@@ -785,14 +786,14 @@ class ListBox(Widget, WidgetContainerMixin):
 
         if offset_inset >= 0:
             if offset_inset >= maxrow:
-                raise ListBoxError, "Invalid offset_inset: %r, only %r rows in list box"% (offset_inset, maxrow)
+                raise ListBoxError("Invalid offset_inset: %r, only %r rows in list box"% (offset_inset, maxrow))
             self.offset_rows = offset_inset
             self.inset_fraction = (0,1)
         else:
             target, _ignore = self._body.get_focus()
             tgt_rows = target.rows( (maxcol,), True )
             if offset_inset + tgt_rows <= 0:
-                raise ListBoxError, "Invalid offset_inset: %r, only %r rows in target!" %(offset_inset, tgt_rows)
+                raise ListBoxError("Invalid offset_inset: %r, only %r rows in target!" %(offset_inset, tgt_rows))
             self.offset_rows = 0
             self.inset_fraction = (-offset_inset,tgt_rows)
         self._invalidate()
@@ -889,7 +890,7 @@ class ListBox(Widget, WidgetContainerMixin):
             self.inset_fraction = (0,1)
         else:
             if offset_inset + tgt_rows <= 0:
-                raise ListBoxError, "Invalid offset_inset: %s, only %s rows in target!" %(offset_inset, tgt_rows)
+                raise ListBoxError("Invalid offset_inset: %s, only %s rows in target!" %(offset_inset, tgt_rows))
             self.offset_rows = 0
             self.inset_fraction = (-offset_inset,tgt_rows)
 
@@ -917,7 +918,7 @@ class ListBox(Widget, WidgetContainerMixin):
             # start from preferred row and move back to closest edge
             (pref_col, pref_row) = cursor_coords
             if pref_row < 0 or pref_row >= tgt_rows:
-                raise ListBoxError, "cursor_coords row outside valid range for target. pref_row:%r target_rows:%r"%(pref_row,tgt_rows)
+                raise ListBoxError("cursor_coords row outside valid range for target. pref_row:%r target_rows:%r"%(pref_row,tgt_rows))
 
             if coming_from=='above':
                 attempt_rows = range( pref_row, -1, -1 )
@@ -940,10 +941,10 @@ class ListBox(Widget, WidgetContainerMixin):
         if offset_rows == 0:
             inum, iden = self.inset_fraction
             if inum < 0 or iden < 0 or inum >= iden:
-                raise ListBoxError, "Invalid inset_fraction: %r"%(self.inset_fraction,)
+                raise ListBoxError("Invalid inset_fraction: %r"%(self.inset_fraction,))
             inset_rows = focus_rows * inum // iden
             if inset_rows and inset_rows >= focus_rows:
-                raise ListBoxError, "urwid inset_fraction error (please report)"
+                raise ListBoxError("urwid inset_fraction error (please report)")
         return offset_rows, inset_rows
 
 
@@ -1272,8 +1273,8 @@ class ListBox(Widget, WidgetContainerMixin):
 
         # choose the topmost selectable and (newly) visible widget
         # search within snap_rows then visible region
-        search_order = ( range( snap_region_start, len(t))
-                + range( snap_region_start-1, -1, -1 ) )
+        search_order = (list(xrange(snap_region_start, len(t)))
+            + list(xrange(snap_region_start-1, -1, -1)))
         #assert 0, repr((t, search_order))
         bad_choices = []
         cut_off_selectable_chosen = 0
@@ -1457,8 +1458,8 @@ class ListBox(Widget, WidgetContainerMixin):
 
         # choose the bottommost selectable and (newly) visible widget
         # search within snap_rows then visible region
-        search_order = ( range( snap_region_start, len(t))
-                + range( snap_region_start-1, -1, -1 ) )
+        search_order = (list(xrange(snap_region_start, len(t)))
+            + list(xrange(snap_region_start-1, -1, -1)))
         #assert 0, repr((t, search_order))
         bad_choices = []
         cut_off_selectable_chosen = 0
diff --git a/urwid/main_loop.py b/urwid/main_loop.py
index ec9c411..442c27d 100755
--- a/urwid/main_loop.py
+++ b/urwid/main_loop.py
@@ -21,6 +21,7 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
 
 import time
 import heapq
@@ -694,7 +695,7 @@ class SelectEventLoop(object):
         """
         A single iteration of the event loop
         """
-        fds = self._watch_files.keys()
+        fds = list(self._watch_files.keys())
         if self._alarms or self._did_something:
             if self._alarms:
                 tm = self._alarms[0][0]
@@ -851,7 +852,7 @@ class GLibEventLoop(object):
             # An exception caused us to exit, raise it now
             exc_info = self._exc_info
             self._exc_info = None
-            raise exc_info[0], exc_info[1], exc_info[2]
+            raise exc_info[0](exc_info[1]).with_traceback(exc_info[2])
 
     def handle_exit(self,f):
         """
@@ -1186,7 +1187,7 @@ class TwistedEventLoop(object):
             # An exception caused us to exit, raise it now
             exc_info = self._exc_info
             self._exc_info = None
-            raise exc_info[0], exc_info[1], exc_info[2]
+            raise exc_info[0](exc_info[1]).with_traceback(exc_info[2])
 
     def handle_exit(self, f, enable_idle=True):
         """
@@ -1206,7 +1207,7 @@ class TwistedEventLoop(object):
                     self.reactor.stop()
             except:
                 import sys
-                print sys.exc_info()
+                print(sys.exc_info())
                 self._exc_info = sys.exc_info()
                 if self.manage_reactor:
                     self.reactor.crash()
@@ -1328,7 +1329,7 @@ class AsyncioEventLoop(object):
         self._loop.set_exception_handler(self._exception_handler)
         self._loop.run_forever()
         if self._exc_info:
-            raise self._exc_info[0], self._exc_info[1], self._exc_info[2]
+            raise self._exc_info[0](self._exc_info[1]).with_traceback(self._exc_info[2])
             self._exc_info = None
 
 
@@ -1357,7 +1358,7 @@ def _refl(name, rval=None, exit=False):
             if args and argd:
                 args = args + ", "
             args = args + ", ".join([k+"="+repr(v) for k,v in argd.items()])
-            print self._name+"("+args+")"
+            print(self._name+"("+args+")")
             if exit:
                 raise ExitMainLoop()
             return self._rval
diff --git a/urwid/monitored_list.py b/urwid/monitored_list.py
index dc67c84..c159064 100755
--- a/urwid/monitored_list.py
+++ b/urwid/monitored_list.py
@@ -19,7 +19,9 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
-from urwid.compat import PYTHON3
+from __future__ import division, print_function
+
+from urwid.compat import PYTHON3, xrange
 
 
 def _call_modified(fn):
@@ -238,7 +240,7 @@ class MonitoredFocusList(MonitoredList):
         """
         num_new_items = len(new_items)
         start, stop, step = indices = slc.indices(len(self))
-        num_removed = len(range(*indices))
+        num_removed = len(list(xrange(*indices)))
 
         focus = self._validate_contents_modified(indices, new_items)
         if focus is not None:
@@ -255,11 +257,11 @@ class MonitoredFocusList(MonitoredList):
         else:
             if not num_new_items:
                 # extended slice being removed
-                if focus in range(start, stop, step):
+                if focus in xrange(start, stop, step):
                     focus += 1
 
                 # adjust for removed items
-                focus -= len(range(start, min(focus, stop), step))
+                focus -= len(list(xrange(start, min(focus, stop), step)))
 
         return min(focus, len(self) + num_new_items - num_removed -1)
 
@@ -303,7 +305,7 @@ class MonitoredFocusList(MonitoredList):
     def __setitem__(self, i, y):
         """
         >>> def modified(indices, new_items):
-        ...     print "range%r <- %r" % (indices, new_items)
+        ...     print("range%r <- %r" % (indices, new_items))
         >>> ml = MonitoredFocusList([0,1,2,3], focus=2)
         >>> ml.set_validate_contents_modified(modified)
         >>> ml[0] = 9
@@ -347,7 +349,7 @@ class MonitoredFocusList(MonitoredList):
     def __imul__(self, n):
         """
         >>> def modified(indices, new_items):
-        ...     print "range%r <- %r" % (indices, list(new_items))
+        ...     print("range%r <- %r" % (indices, list(new_items)))
         >>> ml = MonitoredFocusList([0,1,2], focus=2)
         >>> ml.set_validate_contents_modified(modified)
         >>> ml *= 3
@@ -356,7 +358,7 @@ class MonitoredFocusList(MonitoredList):
         MonitoredFocusList([0, 1, 2, 0, 1, 2, 0, 1, 2], focus=2)
         >>> ml *= 0
         range(0, 9, 1) <- []
-        >>> print ml.focus
+        >>> print(ml.focus)
         None
         """
         if n > 0:
@@ -371,7 +373,7 @@ class MonitoredFocusList(MonitoredList):
     def append(self, item):
         """
         >>> def modified(indices, new_items):
-        ...     print "range%r <- %r" % (indices, new_items)
+        ...     print("range%r <- %r" % (indices, new_items))
         >>> ml = MonitoredFocusList([0,1,2], focus=2)
         >>> ml.set_validate_contents_modified(modified)
         >>> ml.append(6)
@@ -386,7 +388,7 @@ class MonitoredFocusList(MonitoredList):
     def extend(self, items):
         """
         >>> def modified(indices, new_items):
-        ...     print "range%r <- %r" % (indices, list(new_items))
+        ...     print("range%r <- %r" % (indices, list(new_items)))
         >>> ml = MonitoredFocusList([0,1,2], focus=2)
         >>> ml.set_validate_contents_modified(modified)
         >>> ml.extend((6,7,8))
diff --git a/urwid/old_str_util.py b/urwid/old_str_util.py
index 83190f5..2c6d1e0 100755
--- a/urwid/old_str_util.py
+++ b/urwid/old_str_util.py
@@ -19,11 +19,12 @@
 #    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #
 # Urwid web site: http://excess.org/urwid/
-from __future__ import print_function
+
+from __future__ import division, print_function
 
 import re
 
-from urwid.compat import bytes, B, ord2
+from urwid.compat import bytes, B, ord2, text_type
 
 SAFE_ASCII_RE = re.compile(u"^[ -~]*$")
 SAFE_ASCII_BYTES_RE = re.compile(B("^[ -~]*$"))
@@ -241,7 +242,7 @@ def is_wide_char(text, offs):
 
     text may be unicode or a byte string in the target _byte_encoding
     """
-    if isinstance(text, unicode):
+    if isinstance(text, text_type):
         o = ord(text[offs])
         return get_width(o) == 2
     assert isinstance(text, bytes)
@@ -257,7 +258,7 @@ def move_prev_char(text, start_offs, end_offs):
     Return the position of the character before end_offs.
     """
     assert start_offs < end_offs
-    if isinstance(text, unicode):
+    if isinstance(text, text_type):
         return end_offs-1
     assert isinstance(text, bytes)
     if _byte_encoding == "utf8":
@@ -275,7 +276,7 @@ def move_next_char(text, start_offs, end_offs):
     Return the position of the character after start_offs.
     """
     assert start_offs < end_offs
-    if isinstance(text, unicode):
+    if isinstance(text, text_type):
         return start_offs+1
     assert isinstance(text, bytes)
     if _byte_encoding == "utf8":
diff --git a/urwid/raw_display.py b/urwid/raw_display.py
index b619d82..9eadc0e 100644
--- a/urwid/raw_display.py
+++ b/urwid/raw_display.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 """
 Direct terminal UI implementation
 """
@@ -665,8 +667,11 @@ class Screen(BaseScreen, RealTerminal):
         self._setup_G1_done = True
 
 
-    def draw_screen(self, (maxcol, maxrow), r ):
+    def draw_screen(self, maxres, r ):
         """Paint screen with rendered canvas."""
+
+        (maxcol, maxrow) = maxres
+
         assert self._started
 
         assert maxrow == r.rows()
diff --git a/urwid/signals.py b/urwid/signals.py
index 9e93597..0269dfd 100644
--- a/urwid/signals.py
+++ b/urwid/signals.py
@@ -19,6 +19,7 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
 
 import itertools
 import weakref
@@ -33,7 +34,7 @@ class MetaSignals(type):
         signals = d.get("signals", [])
         for superclass in cls.__bases__:
             signals.extend(getattr(superclass, 'signals', []))
-        signals = dict([(x,None) for x in signals]).keys()
+        signals = list(dict([(x,None) for x in signals]).keys())
         d["signals"] = signals
         register_signal(cls, signals)
         super(MetaSignals, cls).__init__(name, bases, d)
diff --git a/urwid/split_repr.py b/urwid/split_repr.py
index fb108b5..3d7cbeb 100755
--- a/urwid/split_repr.py
+++ b/urwid/split_repr.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from inspect import getargspec
 from urwid.compat import PYTHON3, bytes
 
@@ -129,12 +131,12 @@ def remove_defaults(d, fn):
         del args[-1]
 
     # create a dictionary of args with default values
-    ddict = dict(zip(args[len(args) - len(defaults):], defaults))
+    ddict = dict(list(zip(args[len(args) - len(defaults):], defaults)))
 
-    for k, v in d.items():
+    for k in list(d.keys()):
         if k in ddict:
             # remove values that match their defaults
-            if ddict[k] == v:
+            if ddict[k] == d[k]:
                 del d[k]
 
     return d
diff --git a/urwid/tests/test_doctests.py b/urwid/tests/test_doctests.py
index 1720a48..611baf3 100644
--- a/urwid/tests/test_doctests.py
+++ b/urwid/tests/test_doctests.py
@@ -15,6 +15,7 @@ def load_tests(loader, tests, ignore):
         'urwid.split_repr', # override function with same name
         urwid.util,
         urwid.signals,
+        urwid.graphics,
         ]
     for m in module_doctests:
         tests.addTests(doctest.DocTestSuite(m,
diff --git a/urwid/tests/test_vterm.py b/urwid/tests/test_vterm.py
index 075c653..e47398c 100644
--- a/urwid/tests/test_vterm.py
+++ b/urwid/tests/test_vterm.py
@@ -191,7 +191,7 @@ class TermTest(unittest.TestCase):
         self.edgewall()
         self.expect('1-' + ' ' * 76 + '-2' + '\n' * 22
                          + '3-' + ' ' * 76 + '-4')
-        for y in xrange(23, 1, -1):
+        for y in range(23, 1, -1):
             self.resize(80, y, soft=True)
             self.write('\e[%df\e[J3-\e[%d;%df-4' % (y, y, 79))
             desc = "try to rescale to 80x%d." % y
diff --git a/urwid/tests/test_widget.py b/urwid/tests/test_widget.py
index cc8c63e..3f28bc1 100644
--- a/urwid/tests/test_widget.py
+++ b/urwid/tests/test_widget.py
@@ -10,25 +10,25 @@ class TextTest(unittest.TestCase):
         self.t = urwid.Text("I walk the\ncity in the night")
 
     def test1_wrap(self):
-        expected = [B(t) for t in "I walk the","city in   ","the night "]
+        expected = [B(t) for t in ("I walk the","city in   ","the night ")]
         got = self.t.render((10,))._text
         assert got == expected, "got: %r expected: %r" % (got, expected)
 
     def test2_left(self):
         self.t.set_align_mode('left')
-        expected = [B(t) for t in "I walk the        ","city in the night "]
+        expected = [B(t) for t in ("I walk the        ","city in the night ")]
         got = self.t.render((18,))._text
         assert got == expected, "got: %r expected: %r" % (got, expected)
 
     def test3_right(self):
         self.t.set_align_mode('right')
-        expected = [B(t) for t in "        I walk the"," city in the night"]
+        expected = [B(t) for t in ("        I walk the"," city in the night")]
         got = self.t.render((18,))._text
         assert got == expected, "got: %r expected: %r" % (got, expected)
 
     def test4_center(self):
         self.t.set_align_mode('center')
-        expected = [B(t) for t in "    I walk the    "," city in the night"]
+        expected = [B(t) for t in ("    I walk the    "," city in the night")]
         got = self.t.render((18,))._text
         assert got == expected, "got: %r expected: %r" % (got, expected)
 
diff --git a/urwid/text_layout.py b/urwid/text_layout.py
index f09372b..d8663b6 100644
--- a/urwid/text_layout.py
+++ b/urwid/text_layout.py
@@ -19,9 +19,11 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from urwid.util import calc_width, calc_text_pos, calc_trim_text, is_wide_char, \
     move_prev_char, move_next_char
-from urwid.compat import bytes, PYTHON3, B
+from urwid.compat import bytes, PYTHON3, B, xrange
 
 class TextLayout:
     def supports_align_mode(self, align):
@@ -456,8 +458,8 @@ def calc_pos( text, layout, pref_col, row ):
     if pos is not None:
         return pos
 
-    rows_above = range(row-1,-1,-1)
-    rows_below = range(row+1,len(layout))
+    rows_above = list(xrange(row-1,-1,-1))
+    rows_below = list(xrange(row+1,len(layout)))
     while rows_above and rows_below:
         if rows_above:
             r = rows_above.pop(0)
diff --git a/urwid/treetools.py b/urwid/treetools.py
index e948dc6..f2b1aad 100644
--- a/urwid/treetools.py
+++ b/urwid/treetools.py
@@ -20,6 +20,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 """
 Urwid tree view
 
diff --git a/urwid/util.py b/urwid/util.py
index 3569f8c..f57c898 100644
--- a/urwid/util.py
+++ b/urwid/util.py
@@ -20,8 +20,10 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from urwid import escape
-from urwid.compat import bytes
+from urwid.compat import bytes, text_type, text_types
 
 import codecs
 
@@ -108,7 +110,7 @@ def apply_target_encoding( s ):
     """
     Return (encoded byte string, character set rle).
     """
-    if _use_dec_special and type(s) == unicode:
+    if _use_dec_special and type(s) == text_type:
         # first convert drawing characters
         try:
             s = s.translate( escape.DEC_SPECIAL_CHARMAP )
@@ -118,7 +120,7 @@ def apply_target_encoding( s ):
                     escape.ALT_DEC_SPECIAL_CHARS):
                 s = s.replace( c, escape.SO+alt+escape.SI )
 
-    if type(s) == unicode:
+    if type(s) == text_type:
         s = s.replace(escape.SI+escape.SO, u"") # remove redundant shifts
         s = codecs.encode(s, _target_encoding, 'replace')
 
@@ -412,7 +414,7 @@ def _tagmarkup_recurse( tm, attr ):
         attr, element = tm
         return _tagmarkup_recurse( element, attr )
 
-    if not isinstance(tm,(basestring, bytes)):
+    if not isinstance(tm, text_types + (bytes,)):
         raise TagMarkupException("Invalid markup element: %r" % tm)
 
     # text
diff --git a/urwid/version.py b/urwid/version.py
index e34283f..7b70ec5 100644
--- a/urwid/version.py
+++ b/urwid/version.py
@@ -1,3 +1,4 @@
+from __future__ import division, print_function
 
 VERSION = (1, 3, 1)
 __version__ = ''.join(['-.'[type(x) == int]+str(x) for x in VERSION])[1:]
diff --git a/urwid/vterm.py b/urwid/vterm.py
index 0f091ea..0c91ca5 100644
--- a/urwid/vterm.py
+++ b/urwid/vterm.py
@@ -20,6 +20,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 import os
 import sys
 import time
@@ -43,7 +45,7 @@ from urwid.escape import DEC_SPECIAL_CHARS, ALT_DEC_SPECIAL_CHARS
 from urwid.canvas import Canvas
 from urwid.widget import Widget, BOX
 from urwid.display_common import AttrSpec, RealTerminal, _BASIC_COLORS
-from urwid.compat import ord2, chr2, B, bytes, PYTHON3
+from urwid.compat import ord2, chr2, B, bytes, PYTHON3, xrange
 
 ESC = chr(27)
 
diff --git a/urwid/web_display.py b/urwid/web_display.py
index 44a505c..2b2de46 100755
--- a/urwid/web_display.py
+++ b/urwid/web_display.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 """
 Urwid web application display module
 """
@@ -659,7 +661,7 @@ class Screen:
         urwid_id = "%09d%09d"%(random.randrange(10**9),
             random.randrange(10**9))
         self.pipe_name = os.path.join(_prefs.pipe_dir,"urwid"+urwid_id)
-        os.mkfifo(self.pipe_name+".in",0600)
+        os.mkfifo(self.pipe_name+".in",0o600)
         signal.signal(signal.SIGTERM,self._cleanup_pipe)
 
         self.input_fd = os.open(self.pipe_name+".in",
@@ -743,9 +745,11 @@ class Screen:
             rows = MAX_ROWS
         self.screen_size = cols, rows
 
-    def draw_screen(self, (cols, rows), r ):
+    def draw_screen(self, size, r ):
         """Send a screen update to the client."""
 
+        (cols, rows) = size
+
         if cols != self.last_screen_width:
             self.last_screen = {}
 
diff --git a/urwid/widget.py b/urwid/widget.py
index 7901f9b..97cc4b9 100644
--- a/urwid/widget.py
+++ b/urwid/widget.py
@@ -19,8 +19,11 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from operator import attrgetter
 
+from urwid.compat import text_type, with_metaclass
 from urwid.util import (MetaSuper, decompose_tagmarkup, calc_width,
     is_wide_char, move_prev_char, move_next_char)
 from urwid.text_layout import calc_pos, calc_coords, shift_line
@@ -203,15 +206,10 @@ def cache_widget_rows(cls):
     return cached_rows
 
 
-class Widget(object):
+class Widget(with_metaclass(WidgetMeta, object)):
     """
     Widget base class
 
-    .. attribute:: __metaclass__
-       :annotation: = urwid.WidgetMeta
-
-       See :class:`urwid.WidgetMeta` definition
-
     .. attribute:: _selectable
        :annotation: = False
 
@@ -443,8 +441,6 @@ class Widget(object):
        :returns: ``True`` if the position was set successfully anywhere on
                  *row*, ``False`` otherwise
     """
-    __metaclass__ = WidgetMeta
-
     _selectable = False
     _sizing = frozenset([FLOW, BOX, FIXED])
     _command_map = command_map
@@ -827,7 +823,7 @@ class Text(Widget):
         >>> t = Text(('bold', u"stuff"), 'right', 'any')
         >>> t
         <Text flow widget 'stuff' align='right' wrap='any'>
-        >>> print t.text
+        >>> print(t.text)
         stuff
         >>> t.attrib
         [('bold', 5)]
@@ -868,10 +864,10 @@ class Text(Widget):
         :type markup: text markup
 
         >>> t = Text(u"foo")
-        >>> print t.text
+        >>> print(t.text)
         foo
         >>> t.set_text(u"bar")
-        >>> print t.text
+        >>> print(t.text)
         bar
         >>> t.text = u"baz"  # not supported because text stores text but set_text() takes markup
         Traceback (most recent call last):
@@ -1287,10 +1283,10 @@ class Edit(Text):
 
         >>> e = Edit("")
         >>> e.set_caption("cap1")
-        >>> print e.caption
+        >>> print(e.caption)
         cap1
         >>> e.set_caption(('bold', "cap2"))
-        >>> print e.caption
+        >>> print(e.caption)
         cap2
         >>> e.attrib
         [('bold', 4)]
@@ -1360,12 +1356,12 @@ class Edit(Text):
 
         >>> e = Edit()
         >>> e.set_edit_text(u"yes")
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         yes
         >>> e
         <Edit selectable flow widget 'yes' edit_pos=0>
         >>> e.edit_text = u"no"  # Urwid 0.9.9 or later
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         no
         """
         text = self._normalize_to_caption(text)
@@ -1383,9 +1379,9 @@ class Edit(Text):
         Return the edit text for this widget.
 
         >>> e = Edit(u"What? ", u"oh, nothing.")
-        >>> print e.get_edit_text()
+        >>> print(e.get_edit_text())
         oh, nothing.
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         oh, nothing.
         """
         return self._edit_text
@@ -1410,7 +1406,7 @@ class Edit(Text):
         <Edit selectable flow widget '42.5' edit_pos=4>
         >>> e.set_edit_pos(2)
         >>> e.insert_text(u"a")
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         42a.5
         """
         text = self._normalize_to_caption(text)
@@ -1424,8 +1420,8 @@ class Edit(Text):
         Return text converted to the same type as self.caption
         (bytes or unicode)
         """
-        tu = isinstance(text, unicode)
-        cu = isinstance(self._caption, unicode)
+        tu = isinstance(text, text_type)
+        cu = isinstance(self._caption, text_type)
         if tu == cu:
             return text
         if tu:
@@ -1469,12 +1465,12 @@ class Edit(Text):
         >>> e.keypress(size, 'x')
         >>> e.keypress(size, 'left')
         >>> e.keypress(size, '1')
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         1x
         >>> e.keypress(size, 'backspace')
         >>> e.keypress(size, 'end')
         >>> e.keypress(size, '2')
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         x2
         >>> e.keypress(size, 'shift f1')
         'shift f1'
@@ -1483,8 +1479,8 @@ class Edit(Text):
 
         p = self.edit_pos
         if self.valid_char(key):
-            if (isinstance(key, unicode) and not
-                    isinstance(self._caption, unicode)):
+            if (isinstance(key, text_type) and not
+                    isinstance(self._caption, text_type)):
                 # screen is sending us unicode input, must be using utf-8
                 # encoding because that's all we support, so convert it
                 # to bytes to match our caption's type
@@ -1718,10 +1714,10 @@ class IntEdit(Edit):
         >>> e, size = IntEdit(u"", 5002), (10,)
         >>> e.keypress(size, 'home')
         >>> e.keypress(size, 'delete')
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         002
         >>> e.keypress(size, 'end')
-        >>> print e.edit_text
+        >>> print(e.edit_text)
         2
         """
         (maxcol,) = size
@@ -1746,7 +1742,7 @@ class IntEdit(Edit):
         True
         """
         if self.edit_text:
-            return long(self.edit_text)
+            return int(self.edit_text)
         else:
             return 0
 
diff --git a/urwid/wimp.py b/urwid/wimp.py
index ea73fb4..62a0819 100755
--- a/urwid/wimp.py
+++ b/urwid/wimp.py
@@ -19,6 +19,8 @@
 #
 # Urwid web site: http://excess.org/urwid/
 
+from __future__ import division, print_function
+
 from urwid.widget import (Text, WidgetWrap, delegate_to_widget_mixin, BOX,
     FLOW)
 from urwid.canvas import CompositeCanvas
@@ -184,12 +186,12 @@ class CheckBox(WidgetWrap):
         Return label text.
 
         >>> cb = CheckBox(u"Seriously")
-        >>> print cb.get_label()
+        >>> print(cb.get_label())
         Seriously
-        >>> print cb.label
+        >>> print(cb.label)
         Seriously
         >>> cb.set_label([('bright_attr', u"flashy"), u" normal"])
-        >>> print cb.label  #  only text is returned
+        >>> print(cb.label)  #  only text is returned
         flashy normal
         """
         return self._label.text
@@ -507,9 +509,9 @@ class Button(WidgetWrap):
         Return label text.
 
         >>> b = Button(u"Ok")
-        >>> print b.get_label()
+        >>> print(b.get_label())
         Ok
-        >>> print b.label
+        >>> print(b.label)
         Ok
         """
         return self._label.text