From d863068322ef1404cd5b95a8f21b3d2836f942bf Mon Sep 17 00:00:00 2001
From: David Kerkeslager <kerkeslager@gmail.com>
Date: Tue, 11 Apr 2017 16:10:03 -0400
Subject: [PATCH] Start implementing string deserialization

---
 don/binary.py |  2 +-
 don/string.py | 39 ++++++++++++++++++++++++++++++++++++++-
 test_don.py   | 36 ++++++++++++++++++------------------
 3 files changed, 57 insertions(+), 20 deletions(-)

diff --git a/don/binary.py b/don/binary.py
index 295a218..d270f93 100644
--- a/don/binary.py
+++ b/don/binary.py
@@ -185,7 +185,7 @@ _TAGS_TO_PARSERS = {
 def _object_parser(source):
     return _TAGS_TO_PARSERS[source[0]](source[1:])
 
-def _parse(parser, source, consume_all = True):
+def _parse(parser, source):
     result = parser(source)
 
     if result.success and result.remaining == b'':
diff --git a/don/string.py b/don/string.py
index c791387..15ffc10 100644
--- a/don/string.py
+++ b/don/string.py
@@ -58,5 +58,42 @@ def serialize(o):
     
     return _STRING_SERIALIZERS[o.tag](o.value)
 
+def _make_constant_parser(constant, value):
+    def parser(s):
+        if s.startswith(constant):
+            result = _shared.ParseResult(
+                success = True,
+                value = value,
+                remaining = s[len(constant):],
+            )
+            return result
+
+        return _shared._FAILED_PARSE_RESULT
+
+    return parser
+
+_PARSERS = [
+    _make_constant_parser('null', None),
+    _make_constant_parser('true', True),
+    _make_constant_parser('false', False),
+]
+
+def _object_parser(source):
+    for parser in _PARSERS:
+        result = parser(source)
+
+        if result.success:
+            return result
+
+    return _shared._FAILED_PARSE_RESULT
+
+def _parse(parser, source):
+    result = parser(source)
+
+    if result.success and result.remaining.strip() == '':
+        return result.value
+
+    raise Exception('Unparsed trailing characters: "{}"'.format(result.remaining))
+
 def deserialize(s):
-    pass
+    return _parse(_object_parser, s)
diff --git a/test_don.py b/test_don.py
index 3e830c0..df91309 100644
--- a/test_don.py
+++ b/test_don.py
@@ -173,23 +173,23 @@ class TestStringSerialize(unittest.TestCase):
             '{ "foo"utf8: 1i32, "bar"utf8: "baz"utf8 }'
         )
 
-#   class TestStringDeserialize(unittest.TestCase):
-#       def test_deserializes_null(self):
-#           self.assertEqual(
-#               None,
-#               string.deserialize('null'),
-#           )
-#       
-#       def test_deserializes_null(self):
-#           self.assertEqual(
-#               True,
-#               string.deserialize('true'),
-#           )
-#       
-#       def test_deserializes_null(self):
-#           self.assertEqual(
-#               False,
-#               string.deserialize('false'),
-#           )
+class TestStringDeserialize(unittest.TestCase):
+    def test_deserializes_null(self):
+        self.assertEqual(
+            None,
+            string.deserialize('null'),
+        )
+
+    def test_deserializes_null(self):
+        self.assertEqual(
+            True,
+            string.deserialize('true'),
+        )
+
+    def test_deserializes_null(self):
+        self.assertEqual(
+            False,
+            string.deserialize('false'),
+        )
 
 unittest.main()
-- 
2.20.1