diff --git a/examples/base64.py b/examples/base64.py
index 0233ff746609bffde6ec1785bbfc54da3068b93b..f7b68aba2a6d6825ecfa580702f6d6426fe58a56 100644
--- a/examples/base64.py
+++ b/examples/base64.py
@@ -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 1665ccbebfb14470d8ab6dd8ddc6ebd41fb1eff0..84cb2d7379b58cedd468043f82852554dd98b5bb 100644
--- a/examples/base64_sem1.py
+++ b/examples/base64_sem1.py
@@ -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
@@ -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 99158895f87e1447360d850231577f55b0fcb8b5..2e33774f4d4d2836b005bcf1f7ec0950287aaa3b 100644
--- a/examples/base64_sem2.py
+++ b/examples/base64_sem2.py
@@ -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/bindings/python/hammer_tests.py b/src/bindings/python/hammer_tests.py
index ee79caa3970cf32dbf602811957c7155e1db231a..0aead6073023e14c9d11d1b90af3df124745cac7 100644
--- a/src/bindings/python/hammer_tests.py
+++ b/src/bindings/python/hammer_tests.py
@@ -6,215 +6,215 @@ 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
@@ -223,244 +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
 
@@ -469,12 +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
 
@@ -482,15 +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
 
@@ -499,13 +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)