Merge branch 'issue-99-dot-notation' into development:

Addresses issue #99: "Mustache spec v1.1.2 compliance"

HISTORY.rst

@@ -4,10 +4,10 @@ History
 0.6.0 (TBD)
 -----------
 
+* Added support for dot notation and version 1.1.2 of the spec (issue #99). [rbp]
 * Bugfix: falsey values now coerced to strings using str().
-* Bugfix: issue #113: lambda return values for sections no longer pushed
-  onto context stack.
-* Bugfix: issue #114: lists of lambdas for sections were not rendered.
+* Bugfix: lambda return values for sections no longer pushed onto context stack (issue #113).
+* Bugfix: lists of lambdas for sections were not rendered (issue #114).
 
 0.5.1 (2012-04-24)
 ------------------

README.rst

@@ -15,7 +15,7 @@ syntax.  For a more complete (and more current) description of Mustache's
 behavior, see the official `Mustache spec`_.
 
 Pystache is `semantically versioned`_ and can be found on PyPI_.  This
-version of Pystache passes all tests in `version 1.0.3`_ of the spec.
+version of Pystache passes all tests in `version 1.1.2`_ of the spec.
 
 Logo: `David Phillips`_
 
@@ -230,5 +230,5 @@ Authors
 .. _TemplateSpec: https://github.com/defunkt/pystache/blob/master/pystache/template_spec.py
 .. _test: http://packages.python.org/distribute/setuptools.html#test
 .. _tox: http://pypi.python.org/pypi/tox
-.. _version 1.0.3: https://github.com/mustache/spec/tree/48c933b0bb780875acbfd15816297e263c53d6f7
+.. _version 1.1.2: https://github.com/mustache/spec/tree/v1.1.2
 .. _version 2.0.9: http://pypi.python.org/pypi/simplejson/2.0.9

spec @ bf6288ed

-Subproject commit 48c933b0bb780875acbfd15816297e263c53d6f7
+Subproject commit bf6288ed6bd0ce8ccea6f1dac070b3d779132c3b

pystache/context.py

 # coding: utf-8
 
 """
-Exposes a ContextStack class and functions to retrieve names from context.
+Exposes a ContextStack class.
 
 """
 
@@ -27,6 +27,8 @@ def _is_callable(obj):
     return hasattr(obj, '__call__')
 
 
+# TODO: rename item to context (now that we have a separate notion of context stack).
+# TODO: document what a "context" is as opposed to a context stack.
 def _get_value(item, key):
     """
     Retrieve a key's value from an item.
@@ -60,25 +62,6 @@ def _get_value(item, key):
     return _NOT_FOUND
 
 
-# TODO: add some unit tests for this.
-def resolve(context, name):
-    """
-    Resolve the given name against the given context stack.
-
-    This function follows the rules outlined in the section of the spec
-    regarding tag interpolation.
-
-    This function does not coerce the return value to a string.
-
-    """
-    if name == '.':
-        return context.top()
-
-    # The spec says that if the name fails resolution, the result should be
-    # considered falsey, and should interpolate as the empty string.
-    return context.get(name, '')
-
-
 class ContextStack(object):
 
     """
@@ -186,9 +169,65 @@ class ContextStack(object):
 
         return context
 
-    def get(self, key, default=None):
+    # TODO: add some unit tests for this.
+    def get(self, name, default=u''):
         """
-        Query the stack for the given key, and return the resulting value.
+        Resolve a dotted name against the current context stack.
+
+        This function follows the rules outlined in the section of the spec
+        regarding tag interpolation.
+
+        Arguments:
+
+          name: a dotted or non-dotted name.
+
+          default: the value to return if name resolution fails at any point.
+            Defaults to the empty string since the Mustache spec says that if
+            name resolution fails at any point, the result should be considered
+            falsey, and should interpolate as the empty string.
+
+        This function does not coerce the return value to a string.
+
+        """
+        if name == '.':
+            # TODO: should we add a test case for an empty context stack?
+            return self.top()
+
+        parts = name.split('.')
+
+        value = self._get_simple(parts[0])
+
+        for part in parts[1:]:
+            # TODO: consider using EAFP here instead.
+            #   http://docs.python.org/glossary.html#term-eafp
+            if value is _NOT_FOUND:
+                break
+            # The full context stack is not used to resolve the remaining parts.
+            # From the spec--
+            #
+            #   5) If any name parts were retained in step 1, each should be
+            #   resolved against a context stack containing only the result
+            #   from the former resolution.  If any part fails resolution, the
+            #   result should be considered falsey, and should interpolate as
+            #   the empty string.
+            #
+            # TODO: make sure we have a test case for the above point.
+            value = _get_value(value, part)
+
+        if value is _NOT_FOUND:
+            return default
+
+        return value
+
+    # TODO: combine the docstring for this method with the docstring for
+    #   the get() method.
+    def _get_simple(self, key):
+        """
+        Query the stack for a non-dotted key, and return the resulting value.
+
+        Arguments:
+
+          key: a non-dotted name.
 
         This method queries items in the stack in order from last-added
         objects to first (last in, first out).  The value returned is
@@ -253,15 +292,16 @@ class ContextStack(object):
           TODO: explain the rationale for this difference in treatment.
 
         """
-        for obj in reversed(self._stack):
-            val = _get_value(obj, key)
+        val = _NOT_FOUND
+
+        for item in reversed(self._stack):
+            val = _get_value(item, key)
             if val is _NOT_FOUND:
                 continue
             # Otherwise, the key was found.
-            return val
-        # Otherwise, no item in the stack contained the key.
+            break
 
-        return default
+        return val
 
     def push(self, item):
         """

pystache/renderengine.py

@@ -7,7 +7,6 @@ Defines a class responsible for rendering logic.
 
 import re
 
-from pystache.context import resolve
 from pystache.parser import Parser
 
 
@@ -69,7 +68,7 @@ class RenderEngine(object):
         Get a value from the given context as a basestring instance.
 
         """
-        val = resolve(context, tag_name)
+        val = context.get(tag_name)
 
         if callable(val):
             # According to the spec:

pystache/tests/common.py

@@ -191,3 +191,28 @@ class SetupDefaults(object):
         defaults.FILE_ENCODING = self.original_file_encoding
         defaults.STRING_ENCODING = self.original_string_encoding
 
+
+class Attachable(object):
+    """
+    A class that attaches all constructor named parameters as attributes.
+
+    For example--
+
+    >>> obj = Attachable(foo=42, size="of the universe")
+    >>> repr(obj)
+    "Attachable(foo=42, size='of the universe')"
+    >>> obj.foo
+    42
+    >>> obj.size
+    'of the universe'
+
+    """
+    def __init__(self, **kwargs):
+        self.__args__ = kwargs
+        for arg, value in kwargs.iteritems():
+            setattr(self, arg, value)
+
+    def __repr__(self):
+        return "%s(%s)" % (self.__class__.__name__,
+                           ", ".join("%s=%s" % (k, repr(v))
+                                     for k, v in self.__args__.iteritems()))

pystache/tests/test_context.py

@@ -11,7 +11,7 @@ import unittest
 from pystache.context import _NOT_FOUND
 from pystache.context import _get_value
 from pystache.context import ContextStack
-from pystache.tests.common import AssertIsMixin
+from pystache.tests.common import AssertIsMixin, AssertStringMixin, Attachable
 
 class SimpleObject(object):
 
@@ -204,7 +204,7 @@ class GetValueTests(unittest.TestCase, AssertIsMixin):
         self.assertNotFound(item2, 'pop')
 
 
-class ContextStackTests(unittest.TestCase, AssertIsMixin):
+class ContextStackTests(unittest.TestCase, AssertIsMixin, AssertStringMixin):
 
     """
     Test the ContextStack class.
@@ -320,7 +320,7 @@ class ContextStackTests(unittest.TestCase, AssertIsMixin):
 
         """
         context = ContextStack()
-        self.assertTrue(context.get("foo") is None)
+        self.assertString(context.get("foo"), u'')
 
     def test_get__default(self):
         """
@@ -395,3 +395,76 @@ class ContextStackTests(unittest.TestCase, AssertIsMixin):
         # Confirm the original is unchanged.
         self.assertEqual(original.get(key), "buzz")
 
+    def test_dot_notation__dict(self):
+        name = "foo.bar"
+        stack = ContextStack({"foo": {"bar": "baz"}})
+        self.assertEqual(stack.get(name), "baz")
+
+        # Works all the way down
+        name = "a.b.c.d.e.f.g"
+        stack = ContextStack({"a": {"b": {"c": {"d": {"e": {"f": {"g": "w00t!"}}}}}}})
+        self.assertEqual(stack.get(name), "w00t!")
+
+    def test_dot_notation__user_object(self):
+        name = "foo.bar"
+        stack = ContextStack({"foo": Attachable(bar="baz")})
+        self.assertEquals(stack.get(name), "baz")
+
+        # Works on multiple levels, too
+        name = "a.b.c.d.e.f.g"
+        A = Attachable
+        stack = ContextStack({"a": A(b=A(c=A(d=A(e=A(f=A(g="w00t!"))))))})
+        self.assertEquals(stack.get(name), "w00t!")
+
+    def test_dot_notation__mixed_dict_and_obj(self):
+        name = "foo.bar.baz.bak"
+        stack = ContextStack({"foo": Attachable(bar={"baz": Attachable(bak=42)})})
+        self.assertEquals(stack.get(name), 42)
+
+    def test_dot_notation__missing_attr_or_key(self):
+        name = "foo.bar.baz.bak"
+        stack = ContextStack({"foo": {"bar": {}}})
+        self.assertString(stack.get(name), u'')
+
+        stack = ContextStack({"foo": Attachable(bar=Attachable())})
+        self.assertString(stack.get(name), u'')
+
+    def test_dot_notation__missing_part_terminates_search(self):
+        """
+        Test that dotted name resolution terminates on a later part not found.
+
+        Check that if a later dotted name part is not found in the result from
+        the former resolution, then name resolution terminates rather than
+        starting the search over with the next element of the context stack.
+        From the spec (interpolation section)--
+
+          5) If any name parts were retained in step 1, each should be resolved
+          against a context stack containing only the result from the former
+          resolution.  If any part fails resolution, the result should be considered
+          falsey, and should interpolate as the empty string.
+
+        This test case is equivalent to the test case in the following pull
+        request:
+
+          https://github.com/mustache/spec/pull/48
+
+        """
+        stack = ContextStack({'a': {'b': 'A.B'}}, {'a': 'A'})
+        self.assertEqual(stack.get('a'), 'A')
+        self.assertString(stack.get('a.b'), u'')
+        stack.pop()
+        self.assertEqual(stack.get('a.b'), 'A.B')
+
+    def test_dot_notation__autocall(self):
+        name = "foo.bar.baz"
+
+        # When any element in the path is callable, it should be automatically invoked
+        stack = ContextStack({"foo": Attachable(bar=Attachable(baz=lambda: "Called!"))})
+        self.assertEquals(stack.get(name), "Called!")
+
+        class Foo(object):
+            def bar(self):
+                return Attachable(baz='Baz')
+
+        stack = ContextStack({"foo": Foo()})
+        self.assertEquals(stack.get(name), "Baz")

pystache/tests/test_renderengine.py

@@ -11,7 +11,7 @@ from pystache.context import ContextStack
 from pystache import defaults
 from pystache.parser import ParsingError
 from pystache.renderengine import RenderEngine
-from pystache.tests.common import AssertStringMixin
+from pystache.tests.common import AssertStringMixin, Attachable
 
 
 def mock_literal(s):
@@ -580,3 +580,78 @@ class RenderTests(unittest.TestCase, AssertStringMixin):
         expected = u' {{foo}} '
         self._assert_render(expected, '{{=$ $=}} {{foo}} ')
         self._assert_render(expected, '{{=$ $=}} {{foo}} $={{ }}=$')  # was yielding u'  '.
+
+    def test_dot_notation(self):
+        """
+        Test simple dot notation cases.
+
+        Check that we can use dot notation when the variable is a dict,
+        user-defined object, or combination of both.
+
+        """
+        template = 'Hello, {{person.name}}. I see you are {{person.details.age}}.'
+        person = Attachable(name='Biggles', details={'age': 42})
+        context = {'person': person}
+        self._assert_render(u'Hello, Biggles. I see you are 42.', template, context)
+
+    def test_dot_notation__missing_attributes_or_keys(self):
+        """
+        Test dot notation with missing keys or attributes.
+
+        Check that if a key or attribute in a dotted name does not exist, then
+        the tag renders as the empty string.
+
+        """
+        template = """I cannot see {{person.name}}'s age: {{person.age}}.
+        Nor {{other_person.name}}'s: ."""
+        expected = u"""I cannot see Biggles's age: .
+        Nor Mr. Bradshaw's: ."""
+        context = {'person': {'name': 'Biggles'},
+                   'other_person': Attachable(name='Mr. Bradshaw')}
+        self._assert_render(expected, template, context)
+
+    def test_dot_notation__multiple_levels(self):
+        """
+        Test dot notation with multiple levels.
+
+        """
+        template = """Hello, Mr. {{person.name.lastname}}.
+        I see you're back from {{person.travels.last.country.city}}.
+        I'm missing some of your details: {{person.details.private.editor}}."""
+        expected = u"""Hello, Mr. Pither.
+        I see you're back from Cornwall.
+        I'm missing some of your details: ."""
+        context = {'person': {'name': {'firstname': 'unknown', 'lastname': 'Pither'},
+                            'travels': {'last': {'country': {'city': 'Cornwall'}}},
+                            'details': {'public': 'likes cycling'}}}
+        self._assert_render(expected, template, context)
+
+        # It should also work with user-defined objects
+        context = {'person': Attachable(name={'firstname': 'unknown', 'lastname': 'Pither'},
+                                        travels=Attachable(last=Attachable(country=Attachable(city='Cornwall'))),
+                                        details=Attachable())}
+        self._assert_render(expected, template, context)
+
+    def test_dot_notation__missing_part_terminates_search(self):
+        """
+        Test that dotted name resolution terminates on a later part not found.
+
+        Check that if a later dotted name part is not found in the result from
+        the former resolution, then name resolution terminates rather than
+        starting the search over with the next element of the context stack.
+        From the spec (interpolation section)--
+
+          5) If any name parts were retained in step 1, each should be resolved
+          against a context stack containing only the result from the former
+          resolution.  If any part fails resolution, the result should be considered
+          falsey, and should interpolate as the empty string.
+
+        This test case is equivalent to the test case in the following pull
+        request:
+
+          https://github.com/mustache/spec/pull/48
+
+        """
+        template = '{{a.b}} :: ({{#c}}{{a}} :: {{a.b}}{{/c}})'
+        context = {'a': {'b': 'A.B'}, 'c': {'a': 'A'} }
+        self._assert_render(u'A.B :: (A :: )', template, context)