Minor changes addressing PR review issues

8 files changed, 96 insertions, 50 deletions

diff --git a/docs/creating.rst b/docs/creating.rst
index 0a65fd9..bf49f77 100644
--- a/docs/creating.rst
+++ b/docs/creating.rst
@@ -29,16 +29,16 @@ Creating or Extending Validator Classes
         will have :func:`validates` automatically called for the given
         version.
 
-    :argument dict default_types: Deprecated. Please use the type_checker
-        argument instead.
+    :argument dict default_types:
+        .. deprecated:: 2.7.0 Please use the type_checker argument instead.
 
         If set, it provides mappings of JSON types to Python types that will
-        be converted to functions and redefined in this object's TypeChecker
+        be converted to functions and redefined in this object's
+        :class:`jsonschema.TypeChecker`.
 
-    :argument jsonschema.TypeChecker type_checker: an instance
-        of :class:`TypeChecker`, whose :meth:`is_type` will be called to
-        validate the :validator:`type` property If unprovided, a default
-        :class:`TypeChecker` will be created, with no support types.
+    :argument jsonschema.TypeChecker type_checker: a type checker. If
+        unprovided, a :class:`jsonschema.TypeChecker` will created with no
+        supported types.
 
     :returns: a new :class:`jsonschema.IValidator` class
 
@@ -65,9 +65,8 @@ Creating or Extending Validator Classes
 
     :argument str version: a version for the new validator class
 
-    :argument jsonschema.TypeChecker type_checker: an instance
-        of :class:`TypeChecker`. If unprovided, the existing
-        :class:`TypeChecker` will be used.
+    :argument jsonschema.TypeChecker type_checker: a type checker. If
+        unprovided, the existing :class:`jsonschema.TypeChecker` will be used.
 
     :returns: a new :class:`jsonschema.IValidator` class
 
diff --git a/docs/index.rst b/docs/index.rst
index e97278f..93dc058 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -47,7 +47,6 @@ Contents:
     references
     creating
     faq
-    types
 
 
 Indices and tables
diff --git a/docs/types.rst b/docs/types.rst
deleted file mode 100644
index 006060e..0000000
--- a/docs/types.rst
+++ /dev/null
@@ -1,23 +0,0 @@
-.. currentmodule:: jsonschema
-
-=============
-Type Checking
-=============
-
-Each :class:`IValidator` has an associated :class:`TypeChecker`. The
-TypeChecker provides an immutable mapping between names of types and
-functions that can test if an instance is of that type. The defaults are
-suitable for most users - each of the predefined Validators (Draft3, Draft4)
-has a :class:`TypeChecker` that can correctly handle that draft.
-
-See :ref:`validating-types` for an example of providing a custom type check.
-
-.. autoclass:: TypeChecker
-    :members:
-
-.. autoexception:: jsonschema.exceptions.UndefinedTypeCheck
-
-    Raised when trying to remove a type check that is not known to this
-    TypeChecker. Internally this is also raised when calling
-    :meth:`TypeChecker.is_type`, but is caught and re-raised as a
-    :class:`jsonschema.exceptions.UnknownType` exception.
diff --git a/docs/validate.rst b/docs/validate.rst
index 83ee8dc..cded8fb 100644
--- a/docs/validate.rst
+++ b/docs/validate.rst
@@ -32,8 +32,10 @@ classes should adhere to.
         will validate with. It is assumed to be valid, and providing
         an invalid schema can lead to undefined behavior. See
         :meth:`IValidator.check_schema` to validate a schema first.
-    :argument types: Deprecated. Instead, create a custom TypeChecker
-        and extend the validator. See :ref:`validating-types` for details.
+    :argument types:
+        .. deprecated:: 2.7.0
+           Instead, create a custom type checker and extend the validator. See
+           :ref:`validating-types` for details.
 
         If used, this overrides or extends the list of known type when
         validating the :validator:`type` property. Should map strings (type
@@ -50,10 +52,13 @@ classes should adhere to.
 
     .. attribute:: DEFAULT_TYPES
 
-        Deprecated. Under normal usage, this will be an empty dictionary.
+        .. deprecated:: 2.7.0
+           Use of this attribute is deprecated in favour of the the new type
+           checkers.
 
-        If set, it provides mappings of JSON types to Python types that will
-        be converted to functions and redefined in this object's TypeChecker
+        It provides mappings of JSON types to Python types that will
+        be converted to functions and redefined in this object's type checker
+        if one is not provided.
 
     .. attribute:: META_SCHEMA
 
@@ -135,6 +140,27 @@ implementors of validator classes that extend or complement the
 ones included should adhere to it as well. For more information see
 :ref:`creating-validators`.
 
+Type Checking
+-------------
+
+To handle JSON Schema's :validator:`type` property, a :class:`IValidator` uses
+an associated :class:`TypeChecker`. The type checker provides an immutable
+mapping between names of types and functions that can test if an instance is
+of that type. The defaults are suitable for most users - each of the
+predefined Validators (Draft3, Draft4) has a :class:`TypeChecker` that can
+correctly handle that draft.
+
+See :ref:`validating-types` for an example of providing a custom type check.
+
+.. autoclass:: TypeChecker
+    :members:
+
+.. autoexception:: jsonschema.exceptions.UndefinedTypeCheck
+
+    Raised when trying to remove a type check that is not known to this
+    TypeChecker. Internally this is also raised when calling
+    :meth:`TypeChecker.is_type`, but is caught and re-raised as a
+    :class:`jsonschema.exceptions.UnknownType` exception.
 
 .. _validating-types:
 
@@ -166,9 +192,9 @@ existing :class:`TypeChecker` or create a new one. You may then create a new
     class MyInteger(object):
         pass
 
-    def is_my_int(instance):
-        return Draft3Validator.TYPE_CHECKER.is_type(instance, "number") or \
-        isinstance(instance, MyInteger)
+    def is_my_int(checker, instance):
+        return (Draft3Validator.TYPE_CHECKER.is_type(instance, "number") or
+               isinstance(instance, MyInteger))
 
     type_checker = Draft3Validator.TYPE_CHECKER.redefine("number", is_my_int)
 
diff --git a/jsonschema/_types.py b/jsonschema/_types.py
index 2ddcf3d..ad75ff3 100644
--- a/jsonschema/_types.py
+++ b/jsonschema/_types.py
@@ -71,7 +71,7 @@ class TypeChecker(object):
 
         Arguments:
 
-            instance (any primitive type, i.e. str, number, bool):
+            instance (object):
 
                 The instance to check
 
@@ -90,9 +90,11 @@ class TypeChecker(object):
                 if type is unknown to this object.
         """
         try:
-            return self._type_checkers[type](self, instance)
+            fn = self._type_checkers[type]
         except KeyError:
-            raise UndefinedTypeCheck
+            raise UndefinedTypeCheck(type)
+
+        return fn(self, instance)
 
     def redefine(self, type, fn):
         """
@@ -106,8 +108,10 @@ class TypeChecker(object):
 
             fn (callable):
 
-                A function taking exactly one parameter, instance,
-                that checks if instance is of this type.
+                A function taking exactly two parameters - the type checker
+                calling the function and the instance to check. The function
+                should return true if instance is of this type and false
+                otherwise.
 
         Returns:
 
@@ -186,7 +190,7 @@ class TypeChecker(object):
             try:
                 del evolver[type_]
             except KeyError:
-                raise UndefinedTypeCheck
+                raise UndefinedTypeCheck(type_)
 
         return attr.evolve(self, type_checkers=evolver.persistent())
 
diff --git a/jsonschema/compat.py b/jsonschema/compat.py
index 2dd607d..ff91fe6 100644
--- a/jsonschema/compat.py
+++ b/jsonschema/compat.py
@@ -28,7 +28,7 @@ else:
     )
     from urllib import unquote  # noqa
     from urllib2 import urlopen  # noqa
-    str_types = basestring,
+    str_types = basestring
     int_types = int, long
     iteritems = operator.methodcaller("iteritems")
 
diff --git a/jsonschema/exceptions.py b/jsonschema/exceptions.py
index c6ef8c1..d10f246 100644
--- a/jsonschema/exceptions.py
+++ b/jsonschema/exceptions.py
@@ -141,7 +141,18 @@ class RefResolutionError(Exception):
 
 
 class UndefinedTypeCheck(Exception):
-    pass
+    def __init__(self, type):
+        self.type = type
+
+    def __unicode__(self):
+        return "Type %r is unknown to this type checker" % self.type
+
+    if PY3:
+        __str__ = __unicode__
+    else:
+        def __str__(self):
+            return unicode(self).encode("utf-8")
+
 
 class UnknownType(Exception):
     def __init__(self, type, instance, schema):
diff --git a/jsonschema/tests/test_types.py b/jsonschema/tests/test_types.py
index b2747b3..c1a5a48 100644
--- a/jsonschema/tests/test_types.py
+++ b/jsonschema/tests/test_types.py
@@ -59,6 +59,10 @@ class TestTypeChecker(TestCase):
         tc = _types.TypeChecker()
         self.assertEqual(len(tc._type_checkers), 0)
 
+    def test_checks_can_be_added_at_init(self):
+        tc = _types.TypeChecker({"integer": _types.is_integer})
+        self.assertEqual(len(tc._type_checkers), 1)
+
     def test_checks_can_be_added(self):
         tc = _types.TypeChecker()
         tc = tc.redefine("integer", _types.is_integer)
@@ -114,6 +118,32 @@ class TestTypeChecker(TestCase):
 
         self.assertEqual(len(tc._type_checkers), 0)
 
+    def test_unknown_type_raises_exception_on_is_type(self):
+        tc = _types.TypeChecker()
+        with self.assertRaises(UndefinedTypeCheck) as context:
+            tc.is_type(4, 'foobar')
+
+        self.assertIn('foobar', str(context.exception))
+
+    def test_unknown_type_raises_exception_on_remove(self):
+        tc = _types.TypeChecker()
+        with self.assertRaises(UndefinedTypeCheck) as context:
+            tc.remove('foobar')
+
+        self.assertIn('foobar', str(context.exception))
+
+    def test_type_check_can_raise_key_error(self):
+        def raises_keyerror(checker, instance):
+            raise KeyError("internal error")
+
+        tc = _types.TypeChecker({"object": raises_keyerror})
+
+        with self.assertRaises(KeyError) as context:
+            tc.is_type(4, "object")
+
+        self.assertNotIn("object", str(context.exception))
+        self.assertIn("internal error", str(context.exception))
+
 
 class TestCustomTypes(TestCase):