diff --git a/README.md b/README.md
index ee62558..d122fc8 100644
--- a/README.md
+++ b/README.md
@@ -35,8 +35,9 @@ Installing
 * pkg-config (for `scons test`)
 * glib-2.0 (>= 2.29) (for `scons test`)
 * glib-2.0-dev (for `scons test`)
-* [swig](http://swig.org/) (for Python/Perl/PHP bindings; Perl requires >= 2.0.8)
-* python2.7-dev (for Python bindings)
+* [swig](http://swig.org/) (for Python/Perl/PHP bindings; Perl requires >= 2.0.8; Python 3.x requires >= 3.0.0)
+* python2.7-dev (for Python 2 bindings)
+* python3-dev (>= 3.5) (for Python 3 bindings)
 * a JDK (for Java bindings)
 * a working [phpenv](https://github.com/CHH/phpenv) configuration (for PHP bindings)
 * [Ruby](https://www.ruby-lang.org/) >= 1.9.3 and bundler, for the Ruby bindings
@@ -73,7 +74,7 @@ The `examples/` directory contains some simple examples, currently including:
 
 Known Issues
 ============
-The Python bindings only work with Python 2.7. SCons doesn't work with Python 3, and PyCapsule isn't available in 2.6 and below, so 2.7 is all you get. Sorry about that.
+The Python bindings work with Python 2.7, and Python 3.5+.
 
 The requirement for SWIG >= 2.0.8 for Perl bindings is due to a [known bug](http://sourceforge.net/p/swig/patches/324/) in SWIG. [ppa:dns/irc](https://launchpad.net/~dns/+archive/irc) has backports of SWIG 2.0.8 for Ubuntu versions 10.04-12.10; you can also [build SWIG from source](http://www.swig.org/download.html).
 
diff --git a/SConstruct b/SConstruct
index a8203a6..3412c2c 100644
--- a/SConstruct
+++ b/SConstruct
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os
 import os.path
 import platform
@@ -12,6 +15,7 @@ vars = Variables(None, ARGUMENTS)
 vars.Add(PathVariable('DESTDIR', 'Root directory to install in (useful for packaging scripts)', None, PathVariable.PathIsDirCreate))
 vars.Add(PathVariable('prefix', 'Where to install in the FHS', default_install_dir, PathVariable.PathAccept))
 vars.Add(ListVariable('bindings', 'Language bindings to build', 'none', ['cpp', 'dotnet', 'perl', 'php', 'python', 'ruby']))
+vars.Add('python', 'Python interpreter', 'python')
 
 tools = ['default', 'scanreplace']
 if 'dotnet' in ARGUMENTS.get('bindings', []):
@@ -43,9 +47,9 @@ env['prefix'] = os.path.abspath(env['prefix'])
 if 'DESTDIR' in env:
     env['DESTDIR'] = os.path.abspath(env['DESTDIR'])
     if rel_prefix:
-        print >>sys.stderr, '--!!-- You used a relative prefix with a DESTDIR. This is probably not what you'
-        print >>sys.stderr, '--!!-- you want; files will be installed in'
-        print >>sys.stderr, '--!!--    %s' % (calcInstallPath('$prefix'),)
+        print('--!!-- You used a relative prefix with a DESTDIR. This is probably not what you', file=sys.stderr)
+        print('--!!-- you want; files will be installed in', file=sys.stderr)
+        print('--!!--    %s' % (calcInstallPath('$prefix'),), file=sys.stderr)
 
 
 env['libpath'] = calcInstallPath('$prefix', 'lib')
diff --git a/examples/SConscript b/examples/SConscript
index 0694721..b34b85a 100644
--- a/examples/SConscript
+++ b/examples/SConscript
@@ -1,3 +1,5 @@
+from __future__ import absolute_import, division, print_function
+
 Import('env')
 
 example = env.Clone()
diff --git a/examples/base64.py b/examples/base64.py
index 3ffe304..f7b68ab 100644
--- a/examples/base64.py
+++ b/examples/base64.py
@@ -10,7 +10,7 @@
 # base64_sem1.py and base64_sem2.py for examples how to attach appropriate
 # semantic actions to the grammar.
 
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 
 import sys
 
@@ -23,13 +23,13 @@ def init_parser():
     alpha = h.choice(h.ch_range(0x41, 0x5a), h.ch_range(0x61, 0x7a))
 
     # AUX.
-    plus = h.ch('+')
-    slash = h.ch('/')
-    equals = h.ch('=')
+    plus = h.ch(b'+')
+    slash = h.ch(b'/')
+    equals = h.ch(b'=')
 
     bsfdig = h.choice(alpha, digit, plus, slash)
-    bsfdig_4bit = h.in_('AEIMQUYcgkosw048')
-    bsfdig_2bit = h.in_('AQgw')
+    bsfdig_4bit = h.in_(b'AEIMQUYcgkosw048')
+    bsfdig_2bit = h.in_(b'AQgw')
     base64_3 = h.repeat_n(bsfdig, 4)
     base64_2 = h.sequence(bsfdig, bsfdig, bsfdig_4bit, equals)
     base64_1 = h.sequence(bsfdig, bsfdig_2bit, equals, equals)
diff --git a/examples/base64_sem1.py b/examples/base64_sem1.py
index f0676eb..84cb2d7 100644
--- a/examples/base64_sem1.py
+++ b/examples/base64_sem1.py
@@ -13,7 +13,7 @@
 # transform the parse tree in small steps in a bottom-up fashion. Compare
 # base64_sem2.py for an alternative approach using a single top-level action.
 
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 
 import functools
 import sys
@@ -26,7 +26,7 @@ import hammer as h
 
 def act_bsfdig(p, user_data=None):
     # FIXME See the note in init_parser()
-    c = p if isinstance(p, (int, long)) else ord(p)
+    c = p if isinstance(p, h.INTEGER_TYPES) else ord(p)
 
     if 0x41 <= c <= 0x5A: # A-Z
         return c - 0x41
@@ -34,9 +34,9 @@ def act_bsfdig(p, user_data=None):
         return c - 0x61 + 26
     elif 0x30 <= c <= 0x39: # 0-9
         return c - 0x30 + 52
-    elif c == '+':
+    elif c == b'+':
         return 62
-    elif c == '/':
+    elif c == b'/':
         return 63
     else:
         raise ValueError
@@ -65,14 +65,14 @@ def act_base64_n(n, p, user_data=None):
 
     x = 0
     bits = 0
-    for i in xrange(0, n+1):
+    for i in range(0, n+1):
         x <<= 6
         x |= p[i] or 0
         bits += 6
 
     x >>= bits % 8 # align, i.e. cut off extra bits
 
-    for i in xrange(n):
+    for i in range(n):
         item = x & 0xFF
 
         res[n-1-i] = item   # output the last byte and
@@ -118,16 +118,16 @@ def init_parser():
     #      literals, or integers
     digit   = h.ch_range(0x30, 0x39)
     alpha   = h.choice(h.ch_range(0x41, 0x5a), h.ch_range(0x61, 0x7a))
-    space   = h.in_(" \t\n\r\f\v")
+    space   = h.in_(b" \t\n\r\f\v")
 
     # AUX.
-    plus    = h.ch('+')
-    slash   = h.ch('/')
-    equals  = h.action(h.ch('='), act_equals)
+    plus    = h.ch(b'+')
+    slash   = h.ch(b'/')
+    equals  = h.action(h.ch(b'='), act_equals)
 
     bsfdig      = h.action(h.choice(alpha, digit, plus, slash), act_bsfdig)
-    bsfdig_4bit = h.action(h.in_("AEIMQUYcgkosw048"), act_bsfdig_4bit)
-    bsfdig_2bit = h.action(h.in_("AQgw"), act_bsfdig_2bit)
+    bsfdig_4bit = h.action(h.in_(b"AEIMQUYcgkosw048"), act_bsfdig_4bit)
+    bsfdig_2bit = h.action(h.in_(b"AQgw"), act_bsfdig_2bit)
     base64_3    = h.action(h.repeat_n(bsfdig, 4), act_base64_3)
     base64_2    = h.action(h.sequence(bsfdig, bsfdig, bsfdig_4bit, equals),
                            act_base64_2)
diff --git a/examples/base64_sem2.py b/examples/base64_sem2.py
index 6b5f8db..2e33774 100644
--- a/examples/base64_sem2.py
+++ b/examples/base64_sem2.py
@@ -14,7 +14,7 @@
 # for an alternative approach using a fine-grained piece-by-piece
 # transformation.
 
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 
 import functools
 import sys
@@ -28,7 +28,7 @@ import hammer as h
 def bsfdig_value(p):
     """Return the numeric value of a parsed base64 digit.
     """
-    c = p if isinstance(p, (int, long)) else ord(p)
+    c = p if isinstance(p, h.INTEGER_TYPES) else ord(p)
     if c:
         if 0x41 <= c <= 0x5A: # A-Z
             return  c - 0x41
@@ -36,9 +36,9 @@ def bsfdig_value(p):
             return  c - 0x61 + 26
         elif 0x30 <= c <= 0x39: # 0-9
             return  c - 0x30 + 52
-        elif c == '+':
+        elif c == b'+':
             return  62
-        elif c == '/':
+        elif c == b'/':
             return  63
     return 0
 
@@ -109,16 +109,16 @@ def init_parser():
     # CORE
     digit   = h.ch_range(0x30, 0x39)
     alpha   = h.choice(h.ch_range(0x41, 0x5a), h.ch_range(0x61, 0x7a))
-    space   = h.in_(" \t\n\r\f\v")
+    space   = h.in_(b" \t\n\r\f\v")
 
     # AUX.
-    plus    = h.ch('+')
-    slash   = h.ch('/')
-    equals  = h.ch('=')
+    plus    = h.ch(b'+')
+    slash   = h.ch(b'/')
+    equals  = h.ch(b'=')
 
     bsfdig      = h.choice(alpha, digit, plus, slash)
-    bsfdig_4bit = h.in_("AEIMQUYcgkosw048")
-    bsfdig_2bit = h.in_("AQgw")
+    bsfdig_4bit = h.in_(b"AEIMQUYcgkosw048")
+    bsfdig_2bit = h.in_(b"AQgw")
     base64_3    = h.repeat_n(bsfdig, 4)
     base64_2    = h.sequence(bsfdig, bsfdig, bsfdig_4bit, equals)
     base64_1    = h.sequence(bsfdig, bsfdig_2bit, equals, equals)
diff --git a/src/SConscript b/src/SConscript
index 2e446c6..0c4f81e 100644
--- a/src/SConscript
+++ b/src/SConscript
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os.path
 
 Import('env testruns')
diff --git a/src/bindings/cpp/SConscript b/src/bindings/cpp/SConscript
index 9555b98..385759e 100644
--- a/src/bindings/cpp/SConscript
+++ b/src/bindings/cpp/SConscript
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os.path
 Import("env libhammer_shared testruns targets")
 
diff --git a/src/bindings/dotnet/SConscript b/src/bindings/dotnet/SConscript
index 94f874e..62e4b22 100644
--- a/src/bindings/dotnet/SConscript
+++ b/src/bindings/dotnet/SConscript
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os.path
 Import("env libhammer_shared testruns targets")
 
diff --git a/src/bindings/perl/SConscript b/src/bindings/perl/SConscript
index 49b693a..e3e37c6 100644
--- a/src/bindings/perl/SConscript
+++ b/src/bindings/perl/SConscript
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os.path
 Import("env libhammer_shared testruns targets")
 
diff --git a/src/bindings/php/SConscript b/src/bindings/php/SConscript
index 34728af..2846800 100644
--- a/src/bindings/php/SConscript
+++ b/src/bindings/php/SConscript
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os, os.path
 Import('env libhammer_shared testruns')
 
diff --git a/src/bindings/python/SConscript b/src/bindings/python/SConscript
index dac2d95..2ca8ea0 100644
--- a/src/bindings/python/SConscript
+++ b/src/bindings/python/SConscript
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os, os.path
 Import('env libhammer_shared testruns targets')
 
@@ -7,17 +10,18 @@ pythonenv = env.Clone(IMPLICIT_COMMAND_DEPENDENCIES = 0)
 swig = pythonenv.Command("hammer.i", "../swig/hammer.i", Copy("$TARGET", "$SOURCE"))
 setup = ['setup.py']
 pydir = os.path.join(env['BUILD_BASE'], 'src/bindings/python')
-libhammer_python = pythonenv.Command(['hammer.py', 'hammer_wrap.c'], [swig, setup], 'python ' + os.path.join(pydir, 'setup.py') + ' build_ext --inplace')
+pysetup = os.path.join(pydir, 'setup.py')
+libhammer_python = pythonenv.Command(['hammer.py', 'hammer_wrap.c'], [swig, setup],  '%s %s build_ext --inplace' % (env['python'], pysetup))
 Default(libhammer_python)
 
 pytestenv = pythonenv.Clone()
 pytestenv['ENV']['LD_LIBRARY_PATH'] = os.path.dirname(str(libhammer_shared[0]))
 pytests = ['hammer_tests.py']
-pytestexec = pytestenv.Command(['hammer.pyc', 'hammer_tests.pyc'], pytests + libhammer_python, "LD_LIBRARY_PATH=" + os.path.dirname(str(libhammer_shared[0])) + " nosetests -vv $SOURCE")
+pytestexec = pytestenv.Command(['hammer.pyc', 'hammer_tests.pyc'], pytests + libhammer_python, "LD_LIBRARY_PATH=%s %s -mnose -vv $SOURCE" % (os.path.dirname(str(libhammer_shared[0])), env['python']))
 pytest = Alias("testpython", [pytestexec], pytestexec)
 AlwaysBuild(pytestexec)
 testruns.append(pytest)
 
-pyinstallexec = pythonenv.Command(None, libhammer_python, 'python ' + os.path.join(pydir, 'setup.py ') + ' install')
+pyinstallexec = pythonenv.Command(None, libhammer_python, '%s %s install' % (env['python'], pysetup))
 pyinstall = Alias("installpython", [pyinstallexec], pyinstallexec)
 targets.append(pyinstall)
diff --git a/src/bindings/python/hammer_tests.py b/src/bindings/python/hammer_tests.py
index 45a63f4..0aead60 100644
--- a/src/bindings/python/hammer_tests.py
+++ b/src/bindings/python/hammer_tests.py
@@ -1,218 +1,220 @@
+from __future__ import absolute_import, division, print_function
+
 import unittest
 import hammer as h
 
 class TestTokenParser(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.token("95\xa2")
+        cls.parser = h.token(b"95\xa2")
     def test_success(self):
-        self.assertEqual(self.parser.parse("95\xa2"), "95\xa2")
+        self.assertEqual(self.parser.parse(b"95\xa2"), b"95\xa2")
     def test_partial_fails(self):
-        self.assertEqual(self.parser.parse("95"), None)
+        self.assertEqual(self.parser.parse(b"95"), None)
 
 class TestChParser(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser_int = h.ch(0xa2)
-        cls.parser_chr = h.ch("\xa2")
+        cls.parser_chr = h.ch(b"\xa2")
     def test_success(self):
-        self.assertEqual(self.parser_int.parse("\xa2"), 0xa2)
-        self.assertEqual(self.parser_chr.parse("\xa2"), "\xa2")
+        self.assertEqual(self.parser_int.parse(b"\xa2"), 0xa2)
+        self.assertEqual(self.parser_chr.parse(b"\xa2"), b"\xa2")
     def test_failure(self):
-        self.assertEqual(self.parser_int.parse("\xa3"), None)
-        self.assertEqual(self.parser_chr.parse("\xa3"), None)
+        self.assertEqual(self.parser_int.parse(b"\xa3"), None)
+        self.assertEqual(self.parser_chr.parse(b"\xa3"), None)
 
 class TestChRange(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.ch_range("a", "c")
+        cls.parser = h.ch_range(b"a", b"c")
     def test_success(self):
-        self.assertEqual(self.parser.parse("b"), "b")
+        self.assertEqual(self.parser.parse(b"b"), b"b")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("d"), None)
+        self.assertEqual(self.parser.parse(b"d"), None)
 
 class TestInt64(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.int64()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\xff\xff\xff\xfe\x00\x00\x00\x00"), -0x200000000)
+        self.assertEqual(self.parser.parse(b"\xff\xff\xff\xfe\x00\x00\x00\x00"), -0x200000000)
     def test_failure(self):
-        self.assertEqual(self.parser.parse("\xff\xff\xff\xfe\x00\x00\x00"), None)
+        self.assertEqual(self.parser.parse(b"\xff\xff\xff\xfe\x00\x00\x00"), None)
 
 class TestInt32(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.int32()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\xff\xfe\x00\x00"), -0x20000)
-        self.assertEqual(self.parser.parse("\x00\x02\x00\x00"), 0x20000)
+        self.assertEqual(self.parser.parse(b"\xff\xfe\x00\x00"), -0x20000)
+        self.assertEqual(self.parser.parse(b"\x00\x02\x00\x00"), 0x20000)
     def test_failure(self):
-        self.assertEqual(self.parser.parse("\xff\xfe\x00"), None)
-        self.assertEqual(self.parser.parse("\x00\x02\x00"), None)
+        self.assertEqual(self.parser.parse(b"\xff\xfe\x00"), None)
+        self.assertEqual(self.parser.parse(b"\x00\x02\x00"), None)
 
 class TestInt16(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.int16()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\xfe\x00"), -0x200)
-        self.assertEqual(self.parser.parse("\x02\x00"), 0x200)
+        self.assertEqual(self.parser.parse(b"\xfe\x00"), -0x200)
+        self.assertEqual(self.parser.parse(b"\x02\x00"), 0x200)
     def test_failure(self):
-        self.assertEqual(self.parser.parse("\xfe"), None)
-        self.assertEqual(self.parser.parse("\x02"), None)
+        self.assertEqual(self.parser.parse(b"\xfe"), None)
+        self.assertEqual(self.parser.parse(b"\x02"), None)
 
 class TestInt8(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.int8()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\x88"), -0x78)
+        self.assertEqual(self.parser.parse(b"\x88"), -0x78)
     def test_failure(self):
-        self.assertEqual(self.parser.parse(""), None)
+        self.assertEqual(self.parser.parse(b""), None)
 
 class TestUint64(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.uint64()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\x00\x00\x00\x02\x00\x00\x00\x00"), 0x200000000)
+        self.assertEqual(self.parser.parse(b"\x00\x00\x00\x02\x00\x00\x00\x00"), 0x200000000)
     def test_failure(self):
-        self.assertEqual(self.parser.parse("\x00\x00\x00\x02\x00\x00\x00"), None)
+        self.assertEqual(self.parser.parse(b"\x00\x00\x00\x02\x00\x00\x00"), None)
 
 class TestUint32(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.uint32()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\x00\x02\x00\x00"), 0x20000)
+        self.assertEqual(self.parser.parse(b"\x00\x02\x00\x00"), 0x20000)
     def test_failure(self):
-        self.assertEqual(self.parser.parse("\x00\x02\x00"), None)
+        self.assertEqual(self.parser.parse(b"\x00\x02\x00"), None)
 
 class TestUint16(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.uint16()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\x02\x00"), 0x200)
+        self.assertEqual(self.parser.parse(b"\x02\x00"), 0x200)
     def test_failure(self):
-        self.assertEqual(self.parser.parse("\x02"), None)
+        self.assertEqual(self.parser.parse(b"\x02"), None)
 
 class TestUint8(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.uint8()
     def test_success(self):
-        self.assertEqual(self.parser.parse("\x78"), 0x78)
+        self.assertEqual(self.parser.parse(b"\x78"), 0x78)
     def test_failure(self):
-        self.assertEqual(self.parser.parse(""), None)
+        self.assertEqual(self.parser.parse(b""), None)
         
 class TestIntRange(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.int_range(h.uint8(), 3, 10)
     def test_success(self):
-        self.assertEqual(self.parser.parse("\x05"), 5)
+        self.assertEqual(self.parser.parse(b"\x05"), 5)
     def test_failure(self):
-        self.assertEqual(self.parser.parse("\x0b"), None)
+        self.assertEqual(self.parser.parse(b"\x0b"), None)
 
 class TestWhitespace(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.whitespace(h.ch("a"))
+        cls.parser = h.whitespace(h.ch(b"a"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), "a")
-        self.assertEqual(self.parser.parse(" a"), "a")
-        self.assertEqual(self.parser.parse("  a"), "a")
-        self.assertEqual(self.parser.parse("\ta"), "a")
+        self.assertEqual(self.parser.parse(b"a"), b"a")
+        self.assertEqual(self.parser.parse(b" a"), b"a")
+        self.assertEqual(self.parser.parse(b"  a"), b"a")
+        self.assertEqual(self.parser.parse(b"\ta"), b"a")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("_a"), None)
+        self.assertEqual(self.parser.parse(b"_a"), None)
 
 class TestWhitespaceEnd(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.parser = h.whitespace(h.end_p())
     def test_success(self):
-        self.assertEqual(self.parser.parse(""), None) # empty string
-        self.assertEqual(self.parser.parse("  "), None) # empty string
+        self.assertEqual(self.parser.parse(b""), None) # empty string
+        self.assertEqual(self.parser.parse(b"  "), None) # empty string
     def test_failure(self):
-        self.assertEqual(self.parser.parse("  x"), None)
+        self.assertEqual(self.parser.parse(b"  x"), None)
 
 class TestLeft(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.left(h.ch("a"), h.ch(" "))
+        cls.parser = h.left(h.ch(b"a"), h.ch(b" "))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a "), "a")
+        self.assertEqual(self.parser.parse(b"a "), b"a")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a"), None)
-        self.assertEqual(self.parser.parse(" "), None)
-        self.assertEqual(self.parser.parse("ab"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
+        self.assertEqual(self.parser.parse(b" "), None)
+        self.assertEqual(self.parser.parse(b"ab"), None)
 
 class TestRight(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.right(h.ch(" "), h.ch("a"))
+        cls.parser = h.right(h.ch(b" "), h.ch(b"a"))
     def test_success(self):
-        self.assertEqual(self.parser.parse(" a"), "a")
+        self.assertEqual(self.parser.parse(b" a"), b"a")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a"), None)
-        self.assertEqual(self.parser.parse(" "), None)
-        self.assertEqual(self.parser.parse("ba"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
+        self.assertEqual(self.parser.parse(b" "), None)
+        self.assertEqual(self.parser.parse(b"ba"), None)
 
 class TestMiddle(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.middle(h.ch(" "), h.ch("a"), h.ch(" "))
+        cls.parser = h.middle(h.ch(b" "), h.ch(b"a"), h.ch(b" "))
     def test_success(self):
-        self.assertEqual(self.parser.parse(" a "), "a")
+        self.assertEqual(self.parser.parse(b" a "), b"a")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a"), None)
-        self.assertEqual(self.parser.parse(" "), None)
-        self.assertEqual(self.parser.parse(" a"), None)
-        self.assertEqual(self.parser.parse("a "), None)
-        self.assertEqual(self.parser.parse(" b "), None)
-        self.assertEqual(self.parser.parse("ba "), None)
-        self.assertEqual(self.parser.parse(" ab"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
+        self.assertEqual(self.parser.parse(b" "), None)
+        self.assertEqual(self.parser.parse(b" a"), None)
+        self.assertEqual(self.parser.parse(b"a "), None)
+        self.assertEqual(self.parser.parse(b" b "), None)
+        self.assertEqual(self.parser.parse(b"ba "), None)
+        self.assertEqual(self.parser.parse(b" ab"), None)
 
 class TestAction(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.action(h.sequence(h.choice(h.ch("a"), h.ch("A")),
-                                         h.choice(h.ch("b"), h.ch("B"))),
+        cls.parser = h.action(h.sequence(h.choice(h.ch(b"a"), h.ch(b"A")),
+                                         h.choice(h.ch(b"b"), h.ch(b"B"))),
                                 lambda x: [y.upper() for y in x])
     def test_success(self):
-        self.assertEqual(self.parser.parse("ab"), ["A", "B"])
-        self.assertEqual(self.parser.parse("AB"), ["A", "B"])
+        self.assertEqual(self.parser.parse(b"ab"), [b"A", b"B"])
+        self.assertEqual(self.parser.parse(b"AB"), [b"A", b"B"])
     def test_failure(self):
-        self.assertEqual(self.parser.parse("XX"), None)
+        self.assertEqual(self.parser.parse(b"XX"), None)
 
 class TestIn(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.in_("abc")
+        cls.parser = h.in_(b"abc")
     def test_success(self):
-        self.assertEqual(self.parser.parse("b"), "b") 
+        self.assertEqual(self.parser.parse(b"b"), b"b") 
     def test_failure(self):
-        self.assertEqual(self.parser.parse("d"), None)
+        self.assertEqual(self.parser.parse(b"d"), None)
 
 class TestNotIn(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.not_in("abc")
+        cls.parser = h.not_in(b"abc")
     def test_success(self):
-        self.assertEqual(self.parser.parse("d"), "d")
+        self.assertEqual(self.parser.parse(b"d"), b"d")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
 
 class TestEndP(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.end_p())
+        cls.parser = h.sequence(h.ch(b"a"), h.end_p())
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), ("a",))
+        self.assertEqual(self.parser.parse(b"a"), (b"a",))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("aa"), None)
+        self.assertEqual(self.parser.parse(b"aa"), None)
 
 class TestNothingP(unittest.TestCase):
     @classmethod
@@ -221,244 +223,244 @@ class TestNothingP(unittest.TestCase):
     def test_success(self):
         pass
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
 
 class TestSequence(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.ch("b"))
+        cls.parser = h.sequence(h.ch(b"a"), h.ch(b"b"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("ab"), ('a','b'))
+        self.assertEqual(self.parser.parse(b"ab"), (b"a", b"b"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a"), None)
-        self.assertEqual(self.parser.parse("b"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
+        self.assertEqual(self.parser.parse(b"b"), None)
 
 class TestSequenceWhitespace(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.whitespace(h.ch("b")))
+        cls.parser = h.sequence(h.ch(b"a"), h.whitespace(h.ch(b"b")))
     def test_success(self):
-        self.assertEqual(self.parser.parse("ab"), ('a','b'))
-        self.assertEqual(self.parser.parse("a b"), ('a','b'))
-        self.assertEqual(self.parser.parse("a  b"), ('a','b'))
+        self.assertEqual(self.parser.parse(b"ab"), (b"a", b"b"))
+        self.assertEqual(self.parser.parse(b"a b"), (b"a", b"b"))
+        self.assertEqual(self.parser.parse(b"a  b"), (b"a", b"b"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a  c"), None)
+        self.assertEqual(self.parser.parse(b"a  c"), None)
 
 class TestChoice(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.choice(h.ch("a"), h.ch("b"))
+        cls.parser = h.choice(h.ch(b"a"), h.ch(b"b"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), "a")
-        self.assertEqual(self.parser.parse("b"), "b")
+        self.assertEqual(self.parser.parse(b"a"), b"a")
+        self.assertEqual(self.parser.parse(b"b"), b"b")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("c"), None)
+        self.assertEqual(self.parser.parse(b"c"), None)
 
 class TestButNot(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.butnot(h.ch("a"), h.token("ab"))
+        cls.parser = h.butnot(h.ch(b"a"), h.token(b"ab"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), "a")
-        self.assertEqual(self.parser.parse("aa"), "a")
+        self.assertEqual(self.parser.parse(b"a"), b"a")
+        self.assertEqual(self.parser.parse(b"aa"), b"a")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("ab"), None)
+        self.assertEqual(self.parser.parse(b"ab"), None)
 
 class TestButNotRange(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.butnot(h.ch_range("0", "9"), h.ch("6"))
+        cls.parser = h.butnot(h.ch_range(b"0", b"9"), h.ch(b"6"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("4"), "4")
+        self.assertEqual(self.parser.parse(b"4"), b"4")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("6"), None)
+        self.assertEqual(self.parser.parse(b"6"), None)
 
 class TestDifference(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.difference(h.token("ab"), h.ch("a"))
+        cls.parser = h.difference(h.token(b"ab"), h.ch(b"a"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("ab"), "ab")
+        self.assertEqual(self.parser.parse(b"ab"), b"ab")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
 
 class TestXor(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.xor(h.ch_range("0", "6"), h.ch_range("5", "9"))
+        cls.parser = h.xor(h.ch_range(b"0", b"6"), h.ch_range(b"5", b"9"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("0"), "0")
-        self.assertEqual(self.parser.parse("9"), "9")
+        self.assertEqual(self.parser.parse(b"0"), b"0")
+        self.assertEqual(self.parser.parse(b"9"), b"9")
     def test_failure(self):
-        self.assertEqual(self.parser.parse("5"), None)
-        self.assertEqual(self.parser.parse("a"), None)
+        self.assertEqual(self.parser.parse(b"5"), None)
+        self.assertEqual(self.parser.parse(b"a"), None)
 
 class TestMany(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.many(h.choice(h.ch("a"), h.ch("b")))
+        cls.parser = h.many(h.choice(h.ch(b"a"), h.ch(b"b")))
     def test_success(self):
-        self.assertEqual(self.parser.parse(""), ())
-        self.assertEqual(self.parser.parse("a"), ('a',))
-        self.assertEqual(self.parser.parse("b"), ('b',))
-        self.assertEqual(self.parser.parse("aabbaba"), ('a','a','b','b','a','b','a'))
+        self.assertEqual(self.parser.parse(b""), ())
+        self.assertEqual(self.parser.parse(b"a"), (b"a",))
+        self.assertEqual(self.parser.parse(b"b"), (b"b",))
+        self.assertEqual(self.parser.parse(b"aabbaba"), (b"a", b"a", b"b", b"b", b"a", b"b", b"a"))
     def test_failure(self):
         pass
 
 class TestMany1(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.many1(h.choice(h.ch("a"), h.ch("b")))
+        cls.parser = h.many1(h.choice(h.ch(b"a"), h.ch(b"b")))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), ("a",))
-        self.assertEqual(self.parser.parse("b"), ("b",))
-        self.assertEqual(self.parser.parse("aabbaba"), ("a", "a", "b", "b", "a", "b", "a"))
+        self.assertEqual(self.parser.parse(b"a"), (b"a",))
+        self.assertEqual(self.parser.parse(b"b"), (b"b",))
+        self.assertEqual(self.parser.parse(b"aabbaba"), (b"a", b"a", b"b", b"b", b"a", b"b", b"a"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse(""), None)
-        self.assertEqual(self.parser.parse("daabbabadef"), None)
+        self.assertEqual(self.parser.parse(b""), None)
+        self.assertEqual(self.parser.parse(b"daabbabadef"), None)
 
 class TestRepeatN(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.repeat_n(h.choice(h.ch("a"), h.ch("b")), 2)
+        cls.parser = h.repeat_n(h.choice(h.ch(b"a"), h.ch(b"b")), 2)
     def test_success(self):
-        self.assertEqual(self.parser.parse("abdef"), ('a', 'b'))
+        self.assertEqual(self.parser.parse(b"abdef"), (b"a", b"b"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("adef"), None)
-        self.assertEqual(self.parser.parse("dabdef"), None)
+        self.assertEqual(self.parser.parse(b"adef"), None)
+        self.assertEqual(self.parser.parse(b"dabdef"), None)
 
 class TestOptional(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.optional(h.choice(h.ch("b"), h.ch("c"))), h.ch("d"))
+        cls.parser = h.sequence(h.ch(b"a"), h.optional(h.choice(h.ch(b"b"), h.ch(b"c"))), h.ch(b"d"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("abd"), ('a','b','d'))
-        self.assertEqual(self.parser.parse("acd"), ('a','c','d'))
-        self.assertEqual(self.parser.parse("ad"), ('a',h.Placeholder(), 'd'))
+        self.assertEqual(self.parser.parse(b"abd"), (b"a", b"b", b"d"))
+        self.assertEqual(self.parser.parse(b"acd"), (b"a", b"c", b"d"))
+        self.assertEqual(self.parser.parse(b"ad"), (b"a", h.Placeholder(), b"d"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("aed"), None)
-        self.assertEqual(self.parser.parse("ab"), None)
-        self.assertEqual(self.parser.parse("ac"), None)
+        self.assertEqual(self.parser.parse(b"aed"), None)
+        self.assertEqual(self.parser.parse(b"ab"), None)
+        self.assertEqual(self.parser.parse(b"ac"), None)
 
 class TestIgnore(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.ignore(h.ch("b")), h.ch("c"))
+        cls.parser = h.sequence(h.ch(b"a"), h.ignore(h.ch(b"b")), h.ch(b"c"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("abc"), ("a","c"))
+        self.assertEqual(self.parser.parse(b"abc"), (b"a",b"c"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("ac"), None)
+        self.assertEqual(self.parser.parse(b"ac"), None)
 
 class TestSepBy(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sepBy(h.choice(h.ch("1"), h.ch("2"), h.ch("3")), h.ch(","))
+        cls.parser = h.sepBy(h.choice(h.ch(b"1"), h.ch(b"2"), h.ch(b"3")), h.ch(b","))
     def test_success(self):
-        self.assertEqual(self.parser.parse("1,2,3"), ('1','2','3'))
-        self.assertEqual(self.parser.parse("1,3,2"), ('1','3','2'))
-        self.assertEqual(self.parser.parse("1,3"), ('1','3'))
-        self.assertEqual(self.parser.parse("3"), ('3',))
-        self.assertEqual(self.parser.parse(""), ())
+        self.assertEqual(self.parser.parse(b"1,2,3"), (b"1", b"2", b"3"))
+        self.assertEqual(self.parser.parse(b"1,3,2"), (b"1", b"3", b"2"))
+        self.assertEqual(self.parser.parse(b"1,3"), (b"1", b"3"))
+        self.assertEqual(self.parser.parse(b"3"), (b"3",))
+        self.assertEqual(self.parser.parse(b""), ())
     def test_failure(self):
         pass
 
 class TestSepBy1(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sepBy1(h.choice(h.ch("1"), h.ch("2"), h.ch("3")), h.ch(","))
+        cls.parser = h.sepBy1(h.choice(h.ch(b"1"), h.ch(b"2"), h.ch(b"3")), h.ch(b","))
     def test_success(self):
-        self.assertEqual(self.parser.parse("1,2,3"), ('1','2','3'))
-        self.assertEqual(self.parser.parse("1,3,2"), ('1','3','2'))
-        self.assertEqual(self.parser.parse("1,3"), ('1','3'))
-        self.assertEqual(self.parser.parse("3"), ('3',))
+        self.assertEqual(self.parser.parse(b"1,2,3"), (b"1", b"2", b"3"))
+        self.assertEqual(self.parser.parse(b"1,3,2"), (b"1", b"3", b"2"))
+        self.assertEqual(self.parser.parse(b"1,3"), (b"1", b"3"))
+        self.assertEqual(self.parser.parse(b"3"), (b"3",))
     def test_failure(self):
-        self.assertEqual(self.parser.parse(""), None)
+        self.assertEqual(self.parser.parse(b""), None)
 
 class TestEpsilonP1(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.epsilon_p(), h.ch("b"))
+        cls.parser = h.sequence(h.ch(b"a"), h.epsilon_p(), h.ch(b"b"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("ab"), ("a", "b"))
+        self.assertEqual(self.parser.parse(b"ab"), (b"a", b"b"))
     def test_failure(self):
         pass
 
 class TestEpsilonP2(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.epsilon_p(), h.ch("a"))
+        cls.parser = h.sequence(h.epsilon_p(), h.ch(b"a"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), ("a",))
+        self.assertEqual(self.parser.parse(b"a"), (b"a",))
     def test_failure(self):
         pass
 
 class TestEpsilonP3(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.epsilon_p())
+        cls.parser = h.sequence(h.ch(b"a"), h.epsilon_p())
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), ("a",))
+        self.assertEqual(self.parser.parse(b"a"), (b"a",))
     def test_failure(self):
         pass
 
 class TestAttrBool(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.attr_bool(h.many1(h.choice(h.ch("a"), h.ch("b"))),
+        cls.parser = h.attr_bool(h.many1(h.choice(h.ch(b"a"), h.ch(b"b"))),
                                  lambda x: x[0] == x[1])
     def test_success(self):
-        self.assertEqual(self.parser.parse("aa"), ("a", "a"))
-        self.assertEqual(self.parser.parse("bb"), ("b", "b"))
+        self.assertEqual(self.parser.parse(b"aa"), (b"a", b"a"))
+        self.assertEqual(self.parser.parse(b"bb"), (b"b", b"b"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("ab"), None)
+        self.assertEqual(self.parser.parse(b"ab"), None)
 
 class TestAnd1(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.and_(h.ch("0")), h.ch("0"))
+        cls.parser = h.sequence(h.and_(h.ch(b"0")), h.ch(b"0"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("0"), ("0",))
+        self.assertEqual(self.parser.parse(b"0"), (b"0",))
     def test_failure(self):
         pass
 
 class TestAnd2(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.and_(h.ch("0")), h.ch("1"))
+        cls.parser = h.sequence(h.and_(h.ch(b"0")), h.ch(b"1"))
     def test_success(self):
         pass
     def test_failure(self):
-        self.assertEqual(self.parser.parse("0"), None)
+        self.assertEqual(self.parser.parse(b"0"), None)
 
 class TestAnd3(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("1"), h.and_(h.ch("2")))
+        cls.parser = h.sequence(h.ch(b"1"), h.and_(h.ch(b"2")))
     def test_success(self):
-        self.assertEqual(self.parser.parse("12"), ('1',))
+        self.assertEqual(self.parser.parse(b"12"), (b"1",))
     def test_failure(self):
         pass
 
 class TestNot1(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"),
-                                h.choice(h.ch("+"), h.token("++")),
-                                h.ch("b"))
+        cls.parser = h.sequence(h.ch(b"a"),
+                                h.choice(h.ch(b"+"), h.token(b"++")),
+                                h.ch(b"b"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a+b"), ("a", "+", "b"))
+        self.assertEqual(self.parser.parse(b"a+b"), (b"a", b"+", b"b"))
     def test_failure(self):
-        self.assertEqual(self.parser.parse("a++b"), None)
+        self.assertEqual(self.parser.parse(b"a++b"), None)
 
 class TestNot2(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        cls.parser = h.sequence(h.ch("a"), h.choice(h.sequence(h.ch("+"), h.not_(h.ch("+"))),
-                                                    h.token("++")),
-                                h.ch("b"))
+        cls.parser = h.sequence(h.ch(b"a"), h.choice(h.sequence(h.ch(b"+"), h.not_(h.ch(b"+"))),
+                                                    h.token(b"++")),
+                                h.ch(b"b"))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a+b"), ('a', ('+',), 'b'))
-        self.assertEqual(self.parser.parse("a++b"), ('a', "++", 'b'))
+        self.assertEqual(self.parser.parse(b"a+b"), (b"a", (b"+",), b"b"))
+        self.assertEqual(self.parser.parse(b"a++b"), (b"a", b"++", b"b"))
     def test_failure(self):
         pass
 
@@ -467,12 +469,12 @@ class TestNot2(unittest.TestCase):
 # #    @classmethod
 # #    def setUpClass(cls):
 # #        cls.parser = h.indirect()
-# #        a = h.ch("a")
+# #        a = h.ch(b"a")
 # #        h.bind_indirect(cls.parser, h.choice(h.sequence(cls.parser, a), a))
 # #    def test_success(self):
-# #        self.assertEqual(self.parser.parse("a"), "a")
-# #        self.assertEqual(self.parser.parse("aa"), ["a", "a"])
-# #        self.assertEqual(self.parser.parse("aaa"), ["a", "a", "a"])
+# #        self.assertEqual(self.parser.parse(b"a"), b"a")
+# #        self.assertEqual(self.parser.parse(b"aa"), [b"a", b"a"])
+# #        self.assertEqual(self.parser.parse(b"aaa"), [b"a", b"a", b"a"])
 # #    def test_failure(self):
 # #        pass
 
@@ -480,15 +482,15 @@ class TestNot2(unittest.TestCase):
 class TestRightrec(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        #raise unittest.SkipTest("Bind doesn't work right now")
+        #raise unittest.SkipTest(b"Bind doesn't work right now")
         cls.parser = h.indirect()
-        a = h.ch("a")
+        a = h.ch(b"a")
         cls.parser.bind(h.choice(h.sequence(a, cls.parser),
                                  h.epsilon_p()))
     def test_success(self):
-        self.assertEqual(self.parser.parse("a"), ('a',))
-        self.assertEqual(self.parser.parse("aa"), ('a', ('a',)))
-        self.assertEqual(self.parser.parse("aaa"), ('a', ('a', ('a',))))
+        self.assertEqual(self.parser.parse(b"a"), (b"a",))
+        self.assertEqual(self.parser.parse(b"aa"), (b"a", (b"a",)))
+        self.assertEqual(self.parser.parse(b"aaa"), (b"a", (b"a", (b"a",))))
     def test_failure(self):
         pass
 
@@ -497,13 +499,13 @@ class TestRightrec(unittest.TestCase):
 # #    @classmethod
 # #    def setUpClass(cls):
 # #        cls.parser = h.indirect()
-# #        d = h.ch("d")
-# #        p = h.ch("+")
+# #        d = h.ch(b"d")
+# #        p = h.ch(b"+")
 # #        h.bind_indirect(cls.parser, h.choice(h.sequence(cls.parser, p, cls.parser), d))
 # #        # this is supposed to be flattened
 # #    def test_success(self):
-# #        self.assertEqual(self.parser.parse("d"), ["d"])
-# #        self.assertEqual(self.parser.parse("d+d"), ["d", "+", "d"])
-# #        self.assertEqual(self.parser.parse("d+d+d"), ["d", "+", "d", "+", "d"])
+# #        self.assertEqual(self.parser.parse(b"d"), [b"d"])
+# #        self.assertEqual(self.parser.parse(b"d+d"), [b"d", b"+", b"d"])
+# #        self.assertEqual(self.parser.parse(b"d+d+d"), [b"d", b"+", b"d", b"+", b"d"])
 # #    def test_failure(self):
-# #        self.assertEqual(self.parser.parse("d+"), None)
+# #        self.assertEqual(self.parser.parse(b"d+"), None)
diff --git a/src/bindings/ruby/SConscript b/src/bindings/ruby/SConscript
index 6d85a93..d50b644 100644
--- a/src/bindings/ruby/SConscript
+++ b/src/bindings/ruby/SConscript
@@ -1,4 +1,7 @@
 # -*- python -*-
+
+from __future__ import absolute_import, division, print_function
+
 import os.path
 Import("env libhammer_shared testruns targets")
 
diff --git a/src/bindings/swig/hammer.i b/src/bindings/swig/hammer.i
index 122ffe4..0097bdc 100644
--- a/src/bindings/swig/hammer.i
+++ b/src/bindings/swig/hammer.i
@@ -1,4 +1,7 @@
 %module hammer
+%begin %{
+#define SWIG_PYTHON_STRICT_BYTE_CHAR
+%}
 
 %nodefaultctor;
 
@@ -25,6 +28,20 @@
  }
 
 %pythoncode %{
+  try:
+      INTEGER_TYPES = (int, long)
+  except NameError:
+      INTEGER_TYPES = (int,)
+
+  try:
+      TEXT_TYPE = unicode
+      def bchr(i):
+          return chr(i)
+  except NameError:
+      TEXT_TYPE = str
+      def bchr(i):
+          return bytes([i])
+
   class Placeholder(object):
       """The python equivalent of TT_NONE"""
       def __str__(self):
@@ -69,11 +86,11 @@
     PyErr_SetString(PyExc_ValueError, "Expecting a string");
     return NULL;
   } else {
-    $1 = *(uint8_t*)PyString_AsString($input);
+    $1 = *(uint8_t*)PyBytes_AsString($input);
   }
  }
 %typemap(out) HBytes* {
-  $result = PyString_FromStringAndSize((char*)$1->token, $1->len);
+  $result = PyBytes_FromStringAndSize((char*)$1->token, $1->len);
  }
 %typemap(out) struct HCountedArray_* {
   int i;
@@ -173,7 +190,7 @@
       return PyObject_CallFunctionObjArgs(_helper_Placeholder, NULL);
       break;
     case TT_BYTES:
-      return PyString_FromStringAndSize((char*)token->token_data.bytes.token, token->token_data.bytes.len);
+      return PyBytes_FromStringAndSize((char*)token->token_data.bytes.token, token->token_data.bytes.len);
     case TT_SINT:
       // TODO: return PyINT if appropriate
       return PyLong_FromLong(token->token_data.sint);
@@ -250,36 +267,35 @@
 }
 
 %pythoncode %{
-
 def action(p, act):
     return _h_action(p, act)
 def attr_bool(p, pred):
     return _h_attr_bool(p, pred)
 
 def ch(ch):
-    if isinstance(ch, str) or isinstance(ch, unicode):
+    if isinstance(ch, (bytes, TEXT_TYPE)):
         return token(ch)
     else:
         return  _h_ch(ch)
 
 def ch_range(c1, c2):
-    dostr = isinstance(c1, str)
-    dostr2 = isinstance(c2, str)
-    if isinstance(c1, unicode) or isinstance(c2, unicode):
+    dostr = isinstance(c1, bytes)
+    dostr2 = isinstance(c2, bytes)
+    if isinstance(c1, TEXT_TYPE) or isinstance(c2, TEXT_TYPE):
         raise TypeError("ch_range only works on bytes")
     if dostr != dostr2:
         raise TypeError("Both arguments to ch_range must be the same type")
     if dostr:
-        return action(_h_ch_range(c1, c2), chr)
+        return action(_h_ch_range(c1, c2), bchr)
     else:
         return _h_ch_range(c1, c2)
 def epsilon_p(): return _h_epsilon_p()
 def end_p():
     return _h_end_p()
 def in_(charset):
-    return action(_h_in(charset), chr)
+    return action(_h_in(charset), bchr)
 def not_in(charset):
-    return action(_h_not_in(charset), chr)
+    return action(_h_not_in(charset), bchr)
 def not_(p): return _h_not(p)
 def int_range(p, i1, i2):
     return _h_int_range(p, i1, i2)
diff --git a/tools/csharp/__init__.py b/tools/csharp/__init__.py
index af4f519..fbc9d30 100644
--- a/tools/csharp/__init__.py
+++ b/tools/csharp/__init__.py
@@ -21,4 +21,6 @@
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-from csharp import exists, generate
+from __future__ import absolute_import, division, print_function
+
+from .csharp import exists, generate
diff --git a/tools/csharp/csharp.py b/tools/csharp/csharp.py
index 6b38b45..101d3f6 100644
--- a/tools/csharp/csharp.py
+++ b/tools/csharp/csharp.py
@@ -30,6 +30,8 @@
 #  This is an attempt to meld to two based initially on the Microsoft C# tool with amendmnets from the Mono
 #  tool.
 
+from __future__ import absolute_import, division, print_function
+
 import os.path
 import SCons.Builder
 import SCons.Node.FS
@@ -203,7 +205,7 @@ def AddToModPaths(env, files, **kw):
 
 def cscFlags(target, source, env, for_signature):
     listCmd = []
-    if (env.has_key('WINEXE')):
+    if ('WINEXE' in env):
         if (env['WINEXE'] == 1):
             listCmd.append('-t:winexe')
     return listCmd
@@ -243,7 +245,7 @@ def cscSourcesNoResources(target, source, env, for_signature):
 def cscRefs(target, source, env, for_signature):
     listCmd = []
 
-    if (env.has_key('ASSEMBLYREFS')):
+    if ('ASSEMBLYREFS' in env):
         refs = SCons.Util.flatten(env['ASSEMBLYREFS'])
         for ref in refs:
             if SCons.Util.is_String(ref):
@@ -256,7 +258,7 @@ def cscRefs(target, source, env, for_signature):
 def cscMods(target, source, env, for_signature):
     listCmd = []
 
-    if (env.has_key('NETMODULES')):
+    if ('NETMODULES' in env):
         mods = SCons.Util.flatten(env['NETMODULES'])
         for mod in mods:
             listCmd.append('-addmodule:%s' % mod)
@@ -274,7 +276,7 @@ def alLinkSources(target, source, env, for_signature):
             # just treat this as a generic unidentified source file
             listCmd.append('-link:%s' % s.get_string(for_signature))
 
-    if env.has_key('VERSION'):
+    if 'VERSION' in env:
         version = parseVersion(env)
         listCmd.append('-version:%d.%d.%d.%d' % version)
 
@@ -296,7 +298,7 @@ def cliLinkSources(target, source, env, for_signature):
     return listCmd
 
 def add_version(target, source, env):
-    if env.has_key('VERSION'):
+    if 'VERSION' in env:
         if SCons.Util.is_String(target[0]):
             versionfile = target[0] + '_VersionInfo.cs'
         else:
@@ -319,14 +321,14 @@ def lib_emitter(target, source, env):
 def add_depends(target, source, env):
     """Add dependency information before the build order is established"""
 
-    if (env.has_key('NETMODULES')):
+    if ('NETMODULES' in env):
         mods = SCons.Util.flatten(env['NETMODULES'])
         for mod in mods:
             # add as dependency
             for t in target:
                 env.Depends(t, mod)
 
-    if (env.has_key('ASSEMBLYREFS')):
+    if ('ASSEMBLYREFS' in env):
         refs = SCons.Util.flatten(env['ASSEMBLYREFS'])
         for ref in refs:
             # add as dependency
@@ -417,7 +419,7 @@ res_action = SCons.Action.Action('$CLIRCCOM', '$CLIRCCOMSTR')
 
 def res_emitter(target, source, env):
     # prepend NAMESPACE if provided
-    if (env.has_key('NAMESPACE')):
+    if ('NAMESPACE' in env):
         newtargets = []
         for t in target:
             tname = t.name
diff --git a/tools/csharp/mono.py b/tools/csharp/mono.py
index a2cc380..99c509c 100644
--- a/tools/csharp/mono.py
+++ b/tools/csharp/mono.py
@@ -25,6 +25,8 @@
 
 #  This C# Tool for Mono taken from http://www.scons.org/wiki/CsharpBuilder.
 
+from __future__ import absolute_import, division, print_function
+
 import os.path
 import SCons.Builder
 import SCons.Node.FS
diff --git a/tools/scanreplace.py b/tools/scanreplace.py
index 5321e48..81a167e 100644
--- a/tools/scanreplace.py
+++ b/tools/scanreplace.py
@@ -1,3 +1,5 @@
+from __future__ import absolute_import, division, print_function
+
 from string import Template
 
 def replace_action(target, source, env):