ARIA-139 Support attributes

* Fully implement attribute support in parser
* New intrinsic function evaluation mechanism
* Implemented more intrinsic functions, including get_attribute
* Fix to one-on-one relationship back population
* Fixes to TOSCA use case examples
* Indirectly related: re-enabled node_filter mechanism and reworked
filter constraints in order to make them serializable
* utils/type is much more robust now and consolidates all conversions
and names
* Moved dsl_specification to new utils/specification (because utils/type
uses it)
diff --git a/aria/core.py b/aria/core.py
index af1984a..cc943ef 100644
--- a/aria/core.py
+++ b/aria/core.py
@@ -77,10 +77,14 @@
             consumption.ConsumerChain(
                 context,
                 (
+                    consumption.CoerceServiceInstanceValues,
+                    consumption.ValidateServiceInstance,
                     consumption.SatisfyRequirements,
+                    consumption.CoerceServiceInstanceValues,
                     consumption.ValidateCapabilities,
                     consumption.FindHosts,
-                    consumption.ConfigureOperations
+                    consumption.ConfigureOperations,
+                    consumption.CoerceServiceInstanceValues
                 )).consume()
             if context.validation.dump_issues():
                 raise exceptions.InstantiationError('Failed to instantiate service template')
diff --git a/aria/modeling/contraints.py b/aria/modeling/contraints.py
new file mode 100644
index 0000000..107b010
--- /dev/null
+++ b/aria/modeling/contraints.py
@@ -0,0 +1,28 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class NodeTemplateConstraint(object):
+    """
+    Used to constrain requirements for node templates.
+
+    Must be serializable.
+    """
+
+    def matches(self, source_node_template, target_node_template):
+        """
+        Returns true is the target matches the constraint for the source.
+        """
+        raise NotImplementedError
diff --git a/aria/modeling/functions.py b/aria/modeling/functions.py
index 02f4454..06fd19f 100644
--- a/aria/modeling/functions.py
+++ b/aria/modeling/functions.py
@@ -13,20 +13,118 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from ..parser.consumption import ConsumptionContext
+from ..parser.exceptions import InvalidValueError
+from ..utils.collections import OrderedDict
+from . import exceptions
+
+
 class Function(object):
     """
-    An intrinsic function.
+    Base class for intrinsic functions. Serves as a placeholder for a value that should eventually
+    be derived by "evaluating" (calling) the function.
 
-    Serves as a placeholder for a value that should eventually be derived by calling the function.
+    Note that this base class is provided as a convenience and you do not have to inherit it: any
+    object with an ``__evaluate__`` method would be treated similarly.
     """
 
     @property
     def as_raw(self):
         raise NotImplementedError
 
-    def _evaluate(self, context, container):
+    def __evaluate__(self, container_holder):
+        """
+        Evaluates the function if possible. If impossible, raises
+        :class:`CannotEvaluateFunctionException` (do not just return None).
+
+        :rtype: Evaluation (or any object with ``value`` and ``final`` properties)
+        """
+
         raise NotImplementedError
 
     def __deepcopy__(self, memo):
         # Circumvent cloning in order to maintain our state
         return self
+
+
+class Evaluation(object):
+    """
+    An evaluated :class:`Function` return value.
+    """
+
+    def __init__(self, value, final=False):
+        self.value = value
+        self.final = final
+
+
+def evaluate(value, container_holder, report_issues=False): # pylint: disable=too-many-branches
+    """
+    Recursively attempts to call ``__evaluate__``. If an evaluation occurred will return an
+    :class:`Evaluation`, otherwise it will be None. If any evaluation is non-final, then the entire
+    evaluation will also be non-final.
+
+    The ``container_holder`` argument should have three properties: ``container`` should return
+    the model that contains the value, ``service`` should return the containing
+    :class:`aria.modeling.models.Service` model or None, and ``service_template`` should return the
+    containing :class:`aria.modeling.models.ServiceTemplate` model or None.
+    """
+
+    evaluated = False
+    final = True
+
+    if hasattr(value, '__evaluate__'):
+        try:
+            evaluation = value.__evaluate__(container_holder)
+
+            # Verify evaluation structure
+            if (evaluation is None) \
+                or (not hasattr(evaluation, 'value')) \
+                or (not hasattr(evaluation, 'final')):
+                raise InvalidValueError('bad __evaluate__ implementation')
+
+            evaluated = True
+            value = evaluation.value
+            final = evaluation.final
+
+            # The evaluated value might itself be evaluable
+            evaluation = evaluate(value, container_holder, report_issues)
+            if evaluation is not None:
+                value = evaluation.value
+                if not evaluation.final:
+                    final = False
+        except exceptions.CannotEvaluateFunctionException:
+            pass
+        except InvalidValueError as e:
+            if report_issues:
+                context = ConsumptionContext.get_thread_local()
+                context.validation.report(e.issue)
+
+    elif isinstance(value, list):
+        evaluated_list = []
+        for v in value:
+            evaluation = evaluate(v, container_holder, report_issues)
+            if evaluation is not None:
+                evaluated_list.append(evaluation.value)
+                evaluated = True
+                if not evaluation.final:
+                    final = False
+            else:
+                evaluated_list.append(v)
+        if evaluated:
+            value = evaluated_list
+
+    elif isinstance(value, dict):
+        evaluated_dict = OrderedDict()
+        for k, v in value.iteritems():
+            evaluation = evaluate(v, container_holder, report_issues)
+            if evaluation is not None:
+                evaluated_dict[k] = evaluation.value
+                evaluated = True
+                if not evaluation.final:
+                    final = False
+            else:
+                evaluated_dict[k] = v
+        if evaluated:
+            value = evaluated_dict
+
+    return Evaluation(value, final) if evaluated else None
diff --git a/aria/modeling/mixins.py b/aria/modeling/mixins.py
index e6db5a3..38c812d 100644
--- a/aria/modeling/mixins.py
+++ b/aria/modeling/mixins.py
@@ -124,7 +124,7 @@
     def validate(self):
         pass
 
-    def coerce_values(self, container, report_issues):
+    def coerce_values(self, report_issues):
         pass
 
     def dump(self):
diff --git a/aria/modeling/relationship.py b/aria/modeling/relationship.py
index 291d08c..40be5b2 100644
--- a/aria/modeling/relationship.py
+++ b/aria/modeling/relationship.py
@@ -146,13 +146,18 @@
                        false to disable
     :type back_populates: basestring|bool
     """
-    if back_populates is None:
-        back_populates = model_class.__tablename__
+    backref_kwargs = None
+    if back_populates is not NO_BACK_POP:
+        if back_populates is None:
+            back_populates = model_class.__tablename__
+        backref_kwargs = {'name': back_populates, 'uselist': False}
+        back_populates = None
 
     return _relationship(model_class,
                          other_table,
                          fk=fk,
                          back_populates=back_populates,
+                         backref_kwargs=backref_kwargs,
                          other_fk=other_fk)
 
 
@@ -190,6 +195,7 @@
     rel_kwargs.setdefault('cascade', 'all')
     if back_populates is None:
         back_populates = model_class.__tablename__
+
     return _relationship(
         model_class,
         child_table,
@@ -330,10 +336,11 @@
 
     if backref_kwargs:
         assert back_populates is None
-        return relationship(lambda: _get_class_for_table(model_class, other_table_name),
-                            backref=backref(**backref_kwargs),
-                            **relationship_kwargs
-                           )
+        return relationship(
+            lambda: _get_class_for_table(model_class, other_table_name),
+            backref=backref(**backref_kwargs),
+            **relationship_kwargs
+        )
     else:
         if back_populates is not NO_BACK_POP:
             relationship_kwargs['back_populates'] = back_populates
diff --git a/aria/modeling/service_common.py b/aria/modeling/service_common.py
index 1188f34..e9c96a4 100644
--- a/aria/modeling/service_common.py
+++ b/aria/modeling/service_common.py
@@ -23,19 +23,20 @@
 from sqlalchemy.ext.declarative import declared_attr
 
 from ..parser.consumption import ConsumptionContext
-from ..utils import collections, formatting, console
-from .mixins import InstanceModelMixin, TemplateModelMixin
+from ..utils import (collections, formatting, console, caching)
+from ..utils.type import (canonical_type_name, full_type_name)
+from .mixins import (InstanceModelMixin, TemplateModelMixin)
 from . import (
     relationship,
-    utils
+    functions
 )
 
 
-class ParameterBase(TemplateModelMixin):
+class ParameterBase(TemplateModelMixin, caching.HasCachedMethods):
     """
-    Represents a typed value.
+    Represents a typed value. The value can contain nested intrinsic functions.
 
-    This model is used by both service template and service instance elements.
+    This model can be used as the ``container_holder`` argument for :func:`functions.evaluate`.
 
     :ivar name: Name
     :vartype name: basestring
@@ -50,8 +51,120 @@
 
     name = Column(Text)
     type_name = Column(Text)
-    value = Column(PickleType)
     description = Column(Text)
+    _value = Column(PickleType)
+
+    @property
+    def value(self):
+        value = self._value
+        if value is not None:
+            evaluation = functions.evaluate(value, self)
+            if evaluation is not None:
+                value = evaluation.value
+        return value
+
+    @value.setter
+    def value(self, value):
+        self._value = value
+
+    @property
+    @caching.cachedmethod
+    def owner(self):
+        """
+        The sole owner of this parameter, which is another model that relates to it.
+
+        *All* parameters should have an owner model. In case this property method fails to find
+        it, it will raise a ValueError, which should signify an abnormal, orphaned parameter.
+        """
+
+        # Find first non-null relationship
+        for the_relationship in self.__mapper__.relationships:
+            v = getattr(self, the_relationship.key)
+            if v:
+                return v[0] # because we are many-to-many, the back reference will be a list
+
+        raise ValueError('orphaned parameter: does not have an owner: {0}'.format(self.name))
+
+
+    @property
+    @caching.cachedmethod
+    def container(self): # pylint: disable=too-many-return-statements,too-many-branches
+        """
+        The logical container for this parameter, which would be another model: service, node,
+        group, or policy (or their templates).
+
+        The logical container is equivalent to the ``SELF`` keyword used by intrinsic functions in
+        TOSCA.
+
+        *All* parameters should have a container model. In case this property method fails to find
+        it, it will raise a ValueError, which should signify an abnormal, orphaned parameter.
+        """
+
+        from . import models
+
+        container = self.owner
+
+        # Extract interface from operation
+        if isinstance(container, models.Operation):
+            container = container.interface
+        elif isinstance(container, models.OperationTemplate):
+            container = container.interface_template
+
+        # Extract from other models
+        if isinstance(container, models.Interface):
+            container = container.node or container.group or container.relationship
+        elif isinstance(container, models.InterfaceTemplate):
+            container = container.node_template or container.group_template \
+                or container.relationship_template
+        elif isinstance(container, models.Capability) or isinstance(container, models.Artifact):
+            container = container.node
+        elif isinstance(container, models.CapabilityTemplate) \
+            or isinstance(container, models.ArtifactTemplate):
+            container = container.node_template
+        elif isinstance(container, models.Task):
+            container = container.actor
+
+        # Extract node from relationship
+        if isinstance(container, models.Relationship):
+            container = container.source_node
+        elif isinstance(container, models.RelationshipTemplate):
+            container = container.requirement_template.node_template
+
+        if container is not None:
+            return container
+
+        raise ValueError('orphaned parameter: does not have a container: {0}'.format(self.name))
+
+    @property
+    @caching.cachedmethod
+    def service(self):
+        """
+        The :class:`Service` containing this parameter, or None if not contained in a service.
+        """
+
+        from . import models
+        container = self.container
+        if isinstance(container, models.Service):
+            return container
+        elif hasattr(container, 'service'):
+            return container.service
+        return None
+
+    @property
+    @caching.cachedmethod
+    def service_template(self):
+        """
+        The :class:`ServiceTemplate` containing this parameter, or None if not contained in a
+        service template.
+        """
+
+        from . import models
+        container = self.container
+        if isinstance(container, models.ServiceTemplate):
+            return container
+        elif hasattr(container, 'service_template'):
+            return container.service_template
+        return None
 
     @property
     def as_raw(self):
@@ -63,27 +176,30 @@
 
     def instantiate(self, container):
         from . import models
-        return models.Parameter(name=self.name,
+        return models.Parameter(name=self.name, # pylint: disable=unexpected-keyword-arg
                                 type_name=self.type_name,
-                                value=self.value,
+                                _value=self._value,
                                 description=self.description)
 
-    def coerce_values(self, container, report_issues):
-        if self.value is not None:
-            self.value = utils.coerce_value(container, self.value,
-                                            report_issues)
+    def coerce_values(self, report_issues):
+        value = self._value
+        if value is not None:
+            evaluation = functions.evaluate(value, self, report_issues)
+            if (evaluation is not None) and evaluation.final:
+                # A final evaluation can safely replace the existing value
+                self._value = evaluation.value
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
         if self.type_name is not None:
             console.puts('{0}: {1} ({2})'.format(
                 context.style.property(self.name),
-                context.style.literal(self.value),
+                context.style.literal(formatting.as_raw(self.value)),
                 context.style.type(self.type_name)))
         else:
             console.puts('{0}: {1}'.format(
                 context.style.property(self.name),
-                context.style.literal(self.value)))
+                context.style.literal(formatting.as_raw(self.value))))
         if self.description:
             console.puts(context.style.meta(self.description))
 
@@ -101,11 +217,15 @@
         :param description: Description (optional)
         :type description: basestring
         """
-        return cls(name=name,
-                   type_name=formatting.full_type_name(value)
-                   if value is not None else None,
-                   value=value,
-                   description=description)
+
+        from . import models
+        type_name = canonical_type_name(value)
+        if type_name is None:
+            type_name = full_type_name(value)
+        return models.Parameter(name=name, # pylint: disable=unexpected-keyword-arg
+                                type_name=type_name,
+                                value=value,
+                                description=description)
 
 
 class TypeBase(InstanceModelMixin):
@@ -188,7 +308,7 @@
         self._append_raw_children(types)
         return types
 
-    def coerce_values(self, container, report_issues):
+    def coerce_values(self, report_issues):
         pass
 
     def dump(self):
@@ -237,7 +357,7 @@
             ('name', self.name),
             ('value', self.value)))
 
-    def coerce_values(self, container, report_issues):
+    def coerce_values(self, report_issues):
         pass
 
     def instantiate(self, container):
diff --git a/aria/modeling/service_instance.py b/aria/modeling/service_instance.py
index ad8e7ed..1efe1e1 100644
--- a/aria/modeling/service_instance.py
+++ b/aria/modeling/service_instance.py
@@ -251,16 +251,16 @@
         utils.validate_dict_values(self.outputs)
         utils.validate_dict_values(self.workflows)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.meta_data, report_issues)
-        utils.coerce_dict_values(container, self.nodes, report_issues)
-        utils.coerce_dict_values(container, self.groups, report_issues)
-        utils.coerce_dict_values(container, self.policies, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.meta_data, report_issues)
+        utils.coerce_dict_values(self.nodes, report_issues)
+        utils.coerce_dict_values(self.groups, report_issues)
+        utils.coerce_dict_values(self.policies, report_issues)
         if self.substitution is not None:
-            self.substitution.coerce_values(container, report_issues)
-        utils.coerce_dict_values(container, self.inputs, report_issues)
-        utils.coerce_dict_values(container, self.outputs, report_issues)
-        utils.coerce_dict_values(container, self.workflows, report_issues)
+            self.substitution.coerce_values(report_issues)
+        utils.coerce_dict_values(self.inputs, report_issues)
+        utils.coerce_dict_values(self.outputs, report_issues)
+        utils.coerce_dict_values(self.workflows, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -513,6 +513,10 @@
     def properties(cls):
         return relationship.many_to_many(cls, 'parameter', prefix='properties', dict_key='name')
 
+    @declared_attr
+    def attributes(cls):
+        return relationship.many_to_many(cls, 'parameter', prefix='attributes', dict_key='name')
+
     # endregion
 
     description = Column(Text)
@@ -646,6 +650,7 @@
             ('name', self.name),
             ('type_name', self.type.name),
             ('properties', formatting.as_raw_dict(self.properties)),
+            ('attributes', formatting.as_raw_dict(self.properties)),
             ('interfaces', formatting.as_raw_list(self.interfaces)),
             ('artifacts', formatting.as_raw_list(self.artifacts)),
             ('capabilities', formatting.as_raw_list(self.capabilities)),
@@ -664,17 +669,19 @@
         # TODO: validate that node template is of type?
 
         utils.validate_dict_values(self.properties)
+        utils.validate_dict_values(self.attributes)
         utils.validate_dict_values(self.interfaces)
         utils.validate_dict_values(self.artifacts)
         utils.validate_dict_values(self.capabilities)
         utils.validate_list_values(self.outbound_relationships)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(self, self.properties, report_issues)
-        utils.coerce_dict_values(self, self.interfaces, report_issues)
-        utils.coerce_dict_values(self, self.artifacts, report_issues)
-        utils.coerce_dict_values(self, self.capabilities, report_issues)
-        utils.coerce_list_values(self, self.outbound_relationships, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
+        utils.coerce_dict_values(self.attributes, report_issues)
+        utils.coerce_dict_values(self.interfaces, report_issues)
+        utils.coerce_dict_values(self.artifacts, report_issues)
+        utils.coerce_dict_values(self.capabilities, report_issues)
+        utils.coerce_list_values(self.outbound_relationships, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -683,6 +690,7 @@
             console.puts('Type: {0}'.format(context.style.type(self.type.name)))
             console.puts('Template: {0}'.format(context.style.node(self.node_template.name)))
             utils.dump_dict_values(self.properties, 'Properties')
+            utils.dump_dict_values(self.attributes, 'Attributes')
             utils.dump_interfaces(self.interfaces)
             utils.dump_dict_values(self.artifacts, 'Artifacts')
             utils.dump_dict_values(self.capabilities, 'Capabilities')
@@ -797,9 +805,9 @@
         utils.validate_dict_values(self.properties)
         utils.validate_dict_values(self.interfaces)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.properties, report_issues)
-        utils.coerce_dict_values(container, self.interfaces, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
+        utils.coerce_dict_values(self.interfaces, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -916,8 +924,8 @@
     def validate(self):
         utils.validate_dict_values(self.properties)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.properties, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1017,8 +1025,8 @@
     def validate(self):
         utils.validate_dict_values(self.mappings)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.mappings, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.mappings, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1121,7 +1129,7 @@
         return collections.OrderedDict((
             ('name', self.name)))
 
-    def coerce_values(self, container, report_issues):
+    def coerce_values(self, report_issues):
         pass
 
     def validate(self):
@@ -1311,9 +1319,9 @@
         utils.validate_dict_values(self.properties)
         utils.validate_dict_values(self.interfaces)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.properties, report_issues)
-        utils.coerce_dict_values(container, self.interfaces, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
+        utils.coerce_dict_values(self.interfaces, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1451,8 +1459,8 @@
     def validate(self):
         utils.validate_dict_values(self.properties)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.properties, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1598,9 +1606,9 @@
         utils.validate_dict_values(self.inputs)
         utils.validate_dict_values(self.operations)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.inputs, report_issues)
-        utils.coerce_dict_values(container, self.operations, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.inputs, report_issues)
+        utils.coerce_dict_values(self.operations, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1765,8 +1773,8 @@
         # TODO must be associated with interface or service
         utils.validate_dict_values(self.inputs)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.inputs, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.inputs, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1905,8 +1913,8 @@
     def validate(self):
         utils.validate_dict_values(self.properties)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.properties, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
diff --git a/aria/modeling/service_template.py b/aria/modeling/service_template.py
index e3320fa..7a192a7 100644
--- a/aria/modeling/service_template.py
+++ b/aria/modeling/service_template.py
@@ -17,7 +17,6 @@
 
 from __future__ import absolute_import  # so we can import standard 'types'
 
-from types import FunctionType
 from datetime import datetime
 
 from sqlalchemy import (
@@ -25,7 +24,8 @@
     Text,
     Integer,
     Boolean,
-    DateTime
+    DateTime,
+    PickleType
 )
 from sqlalchemy.ext.declarative import declared_attr
 from sqlalchemy.ext.associationproxy import association_proxy
@@ -347,16 +347,16 @@
         if self.artifact_types is not None:
             self.artifact_types.validate()
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.meta_data, report_issues)
-        utils.coerce_dict_values(container, self.node_templates, report_issues)
-        utils.coerce_dict_values(container, self.group_templates, report_issues)
-        utils.coerce_dict_values(container, self.policy_templates, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.meta_data, report_issues)
+        utils.coerce_dict_values(self.node_templates, report_issues)
+        utils.coerce_dict_values(self.group_templates, report_issues)
+        utils.coerce_dict_values(self.policy_templates, report_issues)
         if self.substitution_template is not None:
-            self.substitution_template.coerce_values(container, report_issues)
-        utils.coerce_dict_values(container, self.inputs, report_issues)
-        utils.coerce_dict_values(container, self.outputs, report_issues)
-        utils.coerce_dict_values(container, self.workflow_templates, report_issues)
+            self.substitution_template.coerce_values(report_issues)
+        utils.coerce_dict_values(self.inputs, report_issues)
+        utils.coerce_dict_values(self.outputs, report_issues)
+        utils.coerce_dict_values(self.workflow_templates, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -427,7 +427,7 @@
     :ivar requirement_templates: Potential relationships with other nodes
     :vartype requirement_templates: [:class:`RequirementTemplate`]
     :ivar target_node_template_constraints: Constraints for filtering relationship targets
-    :vartype target_node_template_constraints: [:class:`FunctionType`]
+    :vartype target_node_template_constraints: [:class:`NodeTemplateConstraint`]
     :ivar service_template: Containing service template
     :vartype service_template: :class:`ServiceTemplate`
     :ivar group_templates: We are a member of these groups
@@ -504,6 +504,10 @@
         return relationship.many_to_many(cls, 'parameter', prefix='properties', dict_key='name')
 
     @declared_attr
+    def attributes(cls):
+        return relationship.many_to_many(cls, 'parameter', prefix='attributes', dict_key='name')
+
+    @declared_attr
     def interface_templates(cls):
         return relationship.one_to_many(cls, 'interface_template', dict_key='name')
 
@@ -525,12 +529,12 @@
     default_instances = Column(Integer, default=1)
     min_instances = Column(Integer, default=0)
     max_instances = Column(Integer, default=None)
-    target_node_template_constraints = Column(modeling_types.StrictList(FunctionType))
+    target_node_template_constraints = Column(PickleType)
 
-    def is_target_node_valid(self, target_node_template):
+    def is_target_node_template_valid(self, target_node_template):
         if self.target_node_template_constraints:
-            for node_type_constraint in self.target_node_template_constraints:
-                if not node_type_constraint(target_node_template, self):
+            for node_template_constraint in self.target_node_template_constraints:
+                if not node_template_constraint.matches(self, target_node_template):
                     return False
         return True
 
@@ -544,6 +548,7 @@
             ('min_instances', self.min_instances),
             ('max_instances', self.max_instances),
             ('properties', formatting.as_raw_dict(self.properties)),
+            ('attributes', formatting.as_raw_dict(self.properties)),
             ('interface_templates', formatting.as_raw_list(self.interface_templates)),
             ('artifact_templates', formatting.as_raw_list(self.artifact_templates)),
             ('capability_templates', formatting.as_raw_list(self.capability_templates)),
@@ -564,24 +569,34 @@
                            runtime_properties={},
                            node_template=self)
         utils.instantiate_dict(node, node.properties, self.properties)
+        utils.instantiate_dict(node, node.attributes, self.attributes)
         utils.instantiate_dict(node, node.interfaces, self.interface_templates)
         utils.instantiate_dict(node, node.artifacts, self.artifact_templates)
         utils.instantiate_dict(node, node.capabilities, self.capability_templates)
+
+        # Default attributes
+        if 'tosca_name' in node.attributes:
+            node.attributes['tosca_name'].value = self.name
+        if 'tosca_id' in node.attributes:
+            node.attributes['tosca_id'].value = name
+
         return node
 
     def validate(self):
         utils.validate_dict_values(self.properties)
+        utils.validate_dict_values(self.attributes)
         utils.validate_dict_values(self.interface_templates)
         utils.validate_dict_values(self.artifact_templates)
         utils.validate_dict_values(self.capability_templates)
         utils.validate_list_values(self.requirement_templates)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(self, self.properties, report_issues)
-        utils.coerce_dict_values(self, self.interface_templates, report_issues)
-        utils.coerce_dict_values(self, self.artifact_templates, report_issues)
-        utils.coerce_dict_values(self, self.capability_templates, report_issues)
-        utils.coerce_list_values(self, self.requirement_templates, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
+        utils.coerce_dict_values(self.attributes, report_issues)
+        utils.coerce_dict_values(self.interface_templates, report_issues)
+        utils.coerce_dict_values(self.artifact_templates, report_issues)
+        utils.coerce_dict_values(self.capability_templates, report_issues)
+        utils.coerce_list_values(self.requirement_templates, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -597,6 +612,7 @@
                 if self.max_instances is not None
                 else ' or more'))
             utils.dump_dict_values(self.properties, 'Properties')
+            utils.dump_dict_values(self.attributes, 'Attributes')
             utils.dump_interfaces(self.interface_templates)
             utils.dump_dict_values(self.artifact_templates, 'Artifact templates')
             utils.dump_dict_values(self.capability_templates, 'Capability templates')
@@ -720,9 +736,9 @@
         utils.validate_dict_values(self.properties)
         utils.validate_dict_values(self.interface_templates)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(self, self.properties, report_issues)
-        utils.coerce_dict_values(self, self.interface_templates, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
+        utils.coerce_dict_values(self.interface_templates, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -851,8 +867,8 @@
     def validate(self):
         utils.validate_dict_values(self.properties)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(self, self.properties, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -945,8 +961,8 @@
     def validate(self):
         utils.validate_dict_values(self.mappings)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(self, self.mappings, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.mappings, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1049,7 +1065,7 @@
         return collections.OrderedDict((
             ('name', self.name)))
 
-    def coerce_values(self, container, report_issues):
+    def coerce_values(self, report_issues):
         pass
 
     def instantiate(self, container):
@@ -1113,7 +1129,7 @@
     :ivar target_capability_name: Name of capability in target node (optional)
     :vartype target_capability_name: basestring
     :ivar target_node_template_constraints: Constraints for filtering relationship targets
-    :vartype target_node_template_constraints: [:class:`FunctionType`]
+    :vartype target_node_template_constraints: [:class:`NodeTemplateConstraint`]
     :ivar relationship_template: Template for relationships (optional)
     :vartype relationship_template: :class:`RelationshipTemplate`
     :ivar node_template: Containing node template
@@ -1183,9 +1199,7 @@
 
     @declared_attr
     def relationship_template(cls):
-        return relationship.one_to_one(cls,
-                                       'relationship_template',
-                                       back_populates=relationship.NO_BACK_POP)
+        return relationship.one_to_one(cls, 'relationship_template')
 
     # endregion
 
@@ -1215,18 +1229,18 @@
     # endregion
 
     target_capability_name = Column(Text)
-    target_node_template_constraints = Column(modeling_types.StrictList(FunctionType))
+    target_node_template_constraints = Column(PickleType)
 
     def find_target(self, source_node_template):
         context = ConsumptionContext.get_thread_local()
 
         # We might already have a specific node template, so we'll just verify it
         if self.target_node_template is not None:
-            if not source_node_template.is_target_node_valid(self.target_node_template):
+            if not source_node_template.is_target_node_template_valid(self.target_node_template):
                 context.validation.report('requirement "{0}" of node template "{1}" is for node '
                                           'template "{2}" but it does not match constraints'.format(
                                               self.name,
-                                              self.target_node_template_name,
+                                              self.target_node_template.name,
                                               source_node_template.name),
                                           level=validation.Issue.BETWEEN_TYPES)
             if (self.target_capability_type is not None) \
@@ -1247,7 +1261,7 @@
                 if self.target_node_type.get_descendant(target_node_template.type.name) is None:
                     continue
 
-                if not source_node_template.is_target_node_valid(target_node_template):
+                if not source_node_template.is_target_node_template_valid(target_node_template):
                     continue
 
                 target_node_capability = self.find_target_capability(source_node_template,
@@ -1284,9 +1298,9 @@
         if self.relationship_template:
             self.relationship_template.validate()
 
-    def coerce_values(self, container, report_issues):
+    def coerce_values(self, report_issues):
         if self.relationship_template is not None:
-            self.relationship_template.coerce_values(container, report_issues)
+            self.relationship_template.coerce_values(report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1417,9 +1431,9 @@
         utils.validate_dict_values(self.properties)
         utils.validate_dict_values(self.interface_templates)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(self, self.properties, report_issues)
-        utils.coerce_dict_values(self, self.interface_templates, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
+        utils.coerce_dict_values(self.interface_templates, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1543,8 +1557,8 @@
 
         # Apply requirement constraints
         if requirement.target_node_template_constraints:
-            for node_type_constraint in requirement.target_node_template_constraints:
-                if not node_type_constraint(target_node_template, source_node_template):
+            for node_template_constraint in requirement.target_node_template_constraints:
+                if not node_template_constraint.matches(source_node_template, target_node_template):
                     return False
 
         return True
@@ -1574,8 +1588,8 @@
     def validate(self):
         utils.validate_dict_values(self.properties)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(self, self.properties, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1728,9 +1742,9 @@
         utils.validate_dict_values(self.inputs)
         utils.validate_dict_values(self.operation_templates)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.inputs, report_issues)
-        utils.coerce_dict_values(container, self.operation_templates, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.inputs, report_issues)
+        utils.coerce_dict_values(self.operation_templates, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -1882,7 +1896,7 @@
                 plugin = None
                 implementation = None
         else:
-            # using the execution plugin
+            # Using the execution plugin
             plugin = None
             implementation = self.implementation
 
@@ -1903,8 +1917,8 @@
     def validate(self):
         utils.validate_dict_values(self.inputs)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.inputs, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.inputs, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -2051,8 +2065,8 @@
     def validate(self):
         utils.validate_dict_values(self.properties)
 
-    def coerce_values(self, container, report_issues):
-        utils.coerce_dict_values(container, self.properties, report_issues)
+    def coerce_values(self, report_issues):
+        utils.coerce_dict_values(self.properties, report_issues)
 
     def dump(self):
         context = ConsumptionContext.get_thread_local()
@@ -2128,7 +2142,7 @@
             ('version', self.version),
             ('enabled', self.enabled)))
 
-    def coerce_values(self, container, report_issues):
+    def coerce_values(self, report_issues):
         pass
 
     def resolve(self, model_storage):
diff --git a/aria/modeling/utils.py b/aria/modeling/utils.py
index 91d7b9c..0404fe4 100644
--- a/aria/modeling/utils.py
+++ b/aria/modeling/utils.py
@@ -19,9 +19,6 @@
 
 from . import exceptions
 from ..parser.consumption import ConsumptionContext
-from ..parser.exceptions import InvalidValueError
-from ..parser.presentation import Value
-from ..utils.collections import OrderedDict
 from ..utils.console import puts
 from ..utils.type import validate_value_type
 
@@ -39,6 +36,21 @@
             return JSONEncoder.default(self, o)
 
 
+class NodeTemplateContainerHolder(object):
+    """
+    Wrapper that allows using a :class:`aria.modeling.models.NodeTemplate` model directly as the
+    ``container_holder`` argument for :func:`aria.modeling.functions.evaluate`.
+    """
+
+    def __init__(self, node_template):
+        self.container = node_template
+        self.service = None
+
+    @property
+    def service_template(self):
+        return self.container.service_template
+
+
 def create_inputs(inputs, template_inputs):
     """
     :param inputs: key-value dict
@@ -50,7 +62,7 @@
     from . import models
     input_models = []
     for input_name, input_val in merged_inputs.iteritems():
-        parameter = models.Parameter(
+        parameter = models.Parameter( # pylint: disable=unexpected-keyword-arg
             name=input_name,
             type_name=template_inputs[input_name].type_name,
             description=template_inputs[input_name].description,
@@ -109,39 +121,17 @@
     return merged_inputs
 
 
-def coerce_value(container, value, report_issues=False):
-    if isinstance(value, Value):
-        value = value.value
-
-    if isinstance(value, list):
-        return [coerce_value(container, v, report_issues) for v in value]
-    elif isinstance(value, dict):
-        return OrderedDict((k, coerce_value(container, v, report_issues))
-                           for k, v in value.iteritems())
-    elif hasattr(value, '_evaluate'):
-        context = ConsumptionContext.get_thread_local()
-        try:
-            value = value._evaluate(context, container)
-            value = coerce_value(container, value, report_issues)
-        except exceptions.CannotEvaluateFunctionException:
-            pass
-        except InvalidValueError as e:
-            if report_issues:
-                context.validation.report(e.issue)
-    return value
-
-
-def coerce_dict_values(container, the_dict, report_issues=False):
+def coerce_dict_values(the_dict, report_issues=False):
     if not the_dict:
         return
-    coerce_list_values(container, the_dict.itervalues(), report_issues)
+    coerce_list_values(the_dict.itervalues(), report_issues)
 
 
-def coerce_list_values(container, the_list, report_issues=False):
+def coerce_list_values(the_list, report_issues=False):
     if not the_list:
         return
     for value in the_list:
-        value.coerce_values(container, report_issues)
+        value.coerce_values(report_issues)
 
 
 def validate_dict_values(the_dict):
diff --git a/aria/orchestrator/execution_plugin/instantiation.py b/aria/orchestrator/execution_plugin/instantiation.py
index ce114f0..c09434e 100644
--- a/aria/orchestrator/execution_plugin/instantiation.py
+++ b/aria/orchestrator/execution_plugin/instantiation.py
@@ -15,7 +15,7 @@
 
 # TODO: this module will eventually be moved to a new "aria.instantiation" package
 
-from ...utils.formatting import full_type_name
+from ...utils.type import full_type_name
 from ...utils.collections import OrderedDict
 from ...parser import validation
 from ...parser.consumption import ConsumptionContext
diff --git a/aria/parser/__init__.py b/aria/parser/__init__.py
index 9ab8785..64df88a 100644
--- a/aria/parser/__init__.py
+++ b/aria/parser/__init__.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .specification import dsl_specification, iter_specifications
+from .specification import implements_specification, iter_specifications
 
 
 MODULES = (
@@ -26,5 +26,5 @@
 
 __all__ = (
     'MODULES',
-    'dsl_specification',
+    'implements_specification',
     'iter_specifications')
diff --git a/aria/parser/consumption/__init__.py b/aria/parser/consumption/__init__.py
index 8f6d2b6..76e73be 100644
--- a/aria/parser/consumption/__init__.py
+++ b/aria/parser/consumption/__init__.py
@@ -28,9 +28,11 @@
     Types,
     ServiceInstance,
     FindHosts,
+    ValidateServiceInstance,
     ConfigureOperations,
     SatisfyRequirements,
-    ValidateCapabilities
+    ValidateCapabilities,
+    CoerceServiceInstanceValues
 )
 from .inputs import Inputs
 
@@ -45,7 +47,10 @@
     'ServiceTemplate',
     'Types',
     'ServiceInstance',
-    'Inputs',
+    'FindHosts',
+    'ValidateServiceInstance',
+    'ConfigureOperations',
     'SatisfyRequirements',
-    'ValidateCapabilities'
+    'ValidateCapabilities',
+    'CoerceServiceInstanceValues'
 )
diff --git a/aria/parser/consumption/modeling.py b/aria/parser/consumption/modeling.py
index 771fd7f..44027b9 100644
--- a/aria/parser/consumption/modeling.py
+++ b/aria/parser/consumption/modeling.py
@@ -42,7 +42,7 @@
     """
 
     def consume(self):
-        self.context.modeling.template.coerce_values(None, True)
+        self.context.modeling.template.coerce_values(True)
 
 
 class ValidateServiceTemplate(Consumer):
@@ -116,7 +116,7 @@
     """
 
     def consume(self):
-        self.context.modeling.instance.coerce_values(None, True)
+        self.context.modeling.instance.coerce_values(True)
 
 
 class ValidateServiceInstance(Consumer):
diff --git a/aria/parser/presentation/fields.py b/aria/parser/presentation/fields.py
index da3cb05..7f85723 100644
--- a/aria/parser/presentation/fields.py
+++ b/aria/parser/presentation/fields.py
@@ -21,7 +21,8 @@
 from ...utils.collections import FrozenDict, FrozenList, deepcopy_with_locators, merge, OrderedDict
 from ...utils.caching import cachedmethod
 from ...utils.console import puts
-from ...utils.formatting import as_raw, safe_repr, full_type_name
+from ...utils.formatting import as_raw, safe_repr
+from ...utils.type import full_type_name
 from ...utils.exceptions import print_exception
 from ..exceptions import InvalidValueError
 
diff --git a/aria/parser/presentation/presentation.py b/aria/parser/presentation/presentation.py
index 0f098b5..644d880 100644
--- a/aria/parser/presentation/presentation.py
+++ b/aria/parser/presentation/presentation.py
@@ -15,7 +15,8 @@
 
 from ...utils.caching import HasCachedMethods
 from ...utils.collections import deepcopy_with_locators
-from ...utils.formatting import full_type_name, safe_repr
+from ...utils.formatting import safe_repr
+from ...utils.type import full_type_name
 from ...utils.console import puts
 from ..validation import Issue
 from .null import none_to_null
diff --git a/aria/parser/presentation/utils.py b/aria/parser/presentation/utils.py
index 74adbd1..fbe971b 100644
--- a/aria/parser/presentation/utils.py
+++ b/aria/parser/presentation/utils.py
@@ -15,7 +15,8 @@
 
 from types import FunctionType
 
-from ...utils.formatting import full_type_name, safe_repr
+from ...utils.formatting import safe_repr
+from ...utils.type import full_type_name
 from ..validation import Issue
 from .null import NULL
 
diff --git a/aria/parser/specification.py b/aria/parser/specification.py
index 1df11ce..714bed1 100644
--- a/aria/parser/specification.py
+++ b/aria/parser/specification.py
@@ -17,40 +17,7 @@
 
 from ..extension import parser
 from ..utils.collections import OrderedDict
-from ..utils.formatting import full_type_name
-
-_DSL_SPECIFICATIONS = {}
-
-
-def dsl_specification(section, spec):
-    """
-    Decorator for TOSCA specification.
-
-    Used for documentation and standards compliance.
-    """
-    def decorator(obj):
-        specification = _DSL_SPECIFICATIONS.get(spec)
-
-        if specification is None:
-            specification = {}
-            _DSL_SPECIFICATIONS[spec] = specification
-
-        if section in specification:
-            raise Exception('you cannot specify the same @dsl_specification twice, consider'
-                            ' adding \'-1\', \'-2\', etc.: %s, %s' % (spec, section))
-
-        specification[section] = OrderedDict((
-            ('code', full_type_name(obj)),
-            ('doc', obj.__doc__)))
-
-        try:
-            setattr(obj, '_dsl_specifications', {section: section, spec: spec})
-        except BaseException:
-            pass
-
-        return obj
-
-    return decorator
+from ..utils.specification import (DSL_SPECIFICATIONS, implements_specification) # pylint: disable=unused-import
 
 
 def iter_specifications():
@@ -63,12 +30,10 @@
             details['code'] = sections[k]['code']
             yield k, _fix_details(sections[k], spec)
 
-    for spec, sections in _DSL_SPECIFICATIONS.iteritems():
+    for spec, sections in DSL_SPECIFICATIONS.iteritems():
         yield spec, iter_sections(spec, sections)
 
 
-# Utils
-
 def _section_key(value):
     try:
         parts = value.split('-', 1)
diff --git a/aria/parser/validation/issue.py b/aria/parser/validation/issue.py
index f001efc..db8065d 100644
--- a/aria/parser/validation/issue.py
+++ b/aria/parser/validation/issue.py
@@ -16,7 +16,7 @@
 from __future__ import absolute_import  # so we can import standard 'collections'
 
 from ...utils.collections import OrderedDict
-from ...utils.formatting import full_type_name
+from ...utils.type import full_type_name
 
 
 class Issue(object):
diff --git a/aria/utils/caching.py b/aria/utils/caching.py
index 613ade6..c9e475a 100644
--- a/aria/utils/caching.py
+++ b/aria/utils/caching.py
@@ -65,22 +65,24 @@
             return self.func(*args, **kwargs)
 
         instance = args[0]
-        cache = instance.get_method_cache()
+        if not hasattr(instance, '_method_cache'):
+            instance._method_cache = {}
+        method_cache = instance._method_cache
 
         key = (self.func, args[1:], frozenset(kwargs.items()))
 
         try:
             with self.lock:
-                return_value = cache[key]
+                return_value = method_cache[key]
                 self.hits += 1
         except KeyError:
             return_value = self.func(*args, **kwargs)
             with self.lock:
-                cache[key] = return_value
+                method_cache[key] = return_value
                 self.misses += 1
             # Another thread may override our cache entry here, so we need to read
             # it again to make sure all threads use the same return value
-            return_value = cache.get(key, return_value)
+            return_value = method_cache.get(key, return_value)
 
         return return_value
 
@@ -93,9 +95,6 @@
     def __init__(self, method_cache=None):
         self._method_cache = method_cache or {}
 
-    def get_method_cache(self):
-        return self._method_cache
-
     @property
     def _method_cache_info(self):
         """
diff --git a/aria/utils/formatting.py b/aria/utils/formatting.py
index b5e141d..f96a4ce 100644
--- a/aria/utils/formatting.py
+++ b/aria/utils/formatting.py
@@ -71,18 +71,6 @@
         return super(YamlAsRawDumper, self).represent_data(data)
 
 
-def full_type_name(value):
-    """
-    The full class name of a type or object.
-    """
-
-    if not isinstance(value, type):
-        value = value.__class__
-    module = str(value.__module__)
-    name = str(value.__name__)
-    return name if module == '__builtin__' else '%s.%s' % (module, name)
-
-
 def decode_list(data):
     decoded_list = []
     for item in data:
@@ -163,8 +151,8 @@
             value = value()
     elif isinstance(value, list):
         value = list(value)
-        for i, _ in enumerate(value):
-            value[i] = as_raw(value[i])
+        for i, v in enumerate(value):
+            value[i] = as_raw(v)
     elif isinstance(value, dict):
         value = dict(value)
         for k, v in value.iteritems():
diff --git a/aria/utils/specification.py b/aria/utils/specification.py
new file mode 100644
index 0000000..e74c103
--- /dev/null
+++ b/aria/utils/specification.py
@@ -0,0 +1,53 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .collections import OrderedDict
+
+
+DSL_SPECIFICATIONS = {}
+
+
+def implements_specification(section, spec):
+    """
+    Decorator for specification implementations.
+
+    Used for documentation and standards compliance.
+    """
+
+    from .type import full_type_name
+
+    def decorator(obj):
+        specification = DSL_SPECIFICATIONS.get(spec)
+
+        if specification is None:
+            specification = {}
+            DSL_SPECIFICATIONS[spec] = specification
+
+        if section in specification:
+            raise Exception('you cannot specify the same @implements_specification twice, consider'
+                            ' adding \'-1\', \'-2\', etc.: {0}, {1}'.format(spec, section))
+
+        specification[section] = OrderedDict((
+            ('code', full_type_name(obj)),
+            ('doc', obj.__doc__)))
+
+        try:
+            setattr(obj, '_dsl_specifications', {section: section, spec: spec})
+        except BaseException:
+            pass
+
+        return obj
+
+    return decorator
diff --git a/aria/utils/type.py b/aria/utils/type.py
index dad5427..f08159a 100644
--- a/aria/utils/type.py
+++ b/aria/utils/type.py
@@ -13,49 +13,142 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import datetime
+
+from .specification import implements_specification
+
+
+BASE_TYPES_TO_CANONICAL_NAMES = {
+    # TOSCA aliases:
+    None.__class__: 'null',
+    basestring: 'string',
+    int: 'integer',
+    float: 'float',
+    bool: 'boolean',
+    list: 'list',
+    tuple: 'list',
+    dict: 'map',
+    datetime.datetime: 'timestamp'
+}
+
+NAMES_TO_CANONICAL_TYPES = {
+    # Python:
+    'none': None.__class__,
+    'basestring': unicode,
+    'str': unicode,
+    'unicode': unicode,
+    'int': int,
+    'float': float, # also a TOSCA alias
+    'bool': bool,
+    'list': list, # also a TOSCA alias
+    'tuple': list,
+    'dict': dict,
+    'datetime': datetime.datetime,
+
+    # YAML 1.2:
+    'tag:yaml.org,2002:null': None.__class__,
+    'tag:yaml.org,2002:str': unicode,
+    'tag:yaml.org,2002:integer': int,
+    'tag:yaml.org,2002:float': float,
+    'tag:yaml.org,2002:bool': bool,
+
+    # TOSCA aliases:
+    'null': None.__class__,
+    'string': unicode,
+    'integer': int,
+    'boolean': bool,
+
+    # TOSCA custom types:
+    'map': dict,
+    'timestamp': datetime.datetime
+}
+
+
+def full_type_name(value):
+    """
+    The full class name of a type or instance.
+    """
+
+    if not isinstance(value, type):
+        value = value.__class__
+    module = str(value.__module__)
+    name = str(value.__name__)
+    return name if module == '__builtin__' else '{0}.{1}'.format(module, name)
+
+
+@implements_specification('3.2.1-1', 'tosca-simple-1.0')
+def canonical_type_name(value):
+    """
+    Returns the canonical TOSCA type name of a primitive value, or None if unknown.
+
+    For a list of TOSCA type names, see the `TOSCA Simple Profile v1.0
+    cos01 specification <http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.0/cos01
+    /TOSCA-Simple-Profile-YAML-v1.0-cos01.html#_Toc373867862>`__
+    """
+
+    for the_type, name in BASE_TYPES_TO_CANONICAL_NAMES.iteritems():
+        if isinstance(value, the_type):
+            return name
+    return None
+
+
+@implements_specification('3.2.1-2', 'tosca-simple-1.0')
+def canonical_type(type_name):
+    """
+    Return the canonical type for any Python, YAML, or TOSCA type name or alias, or None if
+    unsupported.
+
+    :param type_name: Type name (case insensitive)
+    """
+
+    return NAMES_TO_CANONICAL_TYPES.get(type_name.lower())
+
 
 def validate_value_type(value, type_name):
     """
-    Validate a value is of a specific type.
+    Validate that a value is of a specific type. Supports Python, YAML, and TOSCA type names and
+    aliases.
+
     A ValueError will be raised on type mismatch.
-    Supports both python and yaml type names.
+
+    :param type_name: Type name (case insensitive)
     """
 
-    #TODO add timestamp type?
-    name_to_type = {
-        'list': list,
-        'dict': dict,
-        'tuple': tuple,
-        'str': str,
-        'unicode': str,
-        'string': str,
-        'int': int,
-        'integer': int,
-        'bool': bool,
-        'boolean': bool,
-        'float': float
-    }
+    the_type = canonical_type(type_name)
+    if the_type is None:
+        raise RuntimeError('Unsupported type name: {0}'.format(type_name))
 
-    type_ = name_to_type.get(type_name.lower())
-    if type_ is None:
-        raise RuntimeError('No supported type_name was provided')
+    # The following Python types do not inherit from the canonical type, but are considered valid
+    if (the_type is unicode) and isinstance(value, str):
+        return
+    if (the_type is list) and isinstance(value, tuple):
+        return
 
-    if not isinstance(value, type_):
+    if not isinstance(value, the_type):
         raise ValueError('Value {0} is not of type {1}'.format(value, type_name))
 
 
-def convert_value_to_type(str_value, type_name):
+def convert_value_to_type(str_value, python_type_name):
+    """
+    Converts a value to a specific Python primitive type.
+
+    A ValueError will be raised for unsupported types or conversion failure.
+
+    :param python_type_name: Python primitive type name (case insensitive)
+    """
+
+    python_type_name = python_type_name.lower()
     try:
-        if type_name.lower() in ['str', 'unicode']:
+        if python_type_name in ('str', 'unicode'):
             return str_value.decode('utf-8')
-        elif type_name.lower() == 'int':
+        elif python_type_name == 'int':
             return int(str_value)
-        elif type_name.lower() == 'bool':
+        elif python_type_name == 'bool':
             return bool(str_value)
-        elif type_name.lower() == 'float':
+        elif python_type_name == 'float':
             return float(str_value)
         else:
-            raise ValueError('No supported type_name was provided')
+            raise ValueError('Unsupported Python type name: {0}'.format(python_type_name))
     except ValueError:
-        raise ValueError('Trying to convert {0} to {1} failed'.format(str_value,
-                                                                      type_name))
+        raise ValueError('Failed to to convert {0} to {1}'.format(str_value,
+                                                                  python_type_name))
diff --git a/examples/tosca-simple-1.0/use-cases/block-storage-1/block-storage-1.yaml b/examples/tosca-simple-1.0/use-cases/block-storage-1/block-storage-1.yaml
index ff6dc92..b912fb2 100644
--- a/examples/tosca-simple-1.0/use-cases/block-storage-1/block-storage-1.yaml
+++ b/examples/tosca-simple-1.0/use-cases/block-storage-1/block-storage-1.yaml
@@ -65,4 +65,4 @@
       value: { get_attribute: [ my_server, private_address ] }
     volume_id:
       description: The volume id of the block storage instance.
-      value: { get_attribute: [ my_storage, volume_id ] }
+      value: { get_property: [ my_storage, volume_id ] } # ARIA NOTE: wrong in spec
diff --git a/examples/tosca-simple-1.0/use-cases/block-storage-2/block-storage-2.yaml b/examples/tosca-simple-1.0/use-cases/block-storage-2/block-storage-2.yaml
index 09c30a7..ac475cf 100644
--- a/examples/tosca-simple-1.0/use-cases/block-storage-2/block-storage-2.yaml
+++ b/examples/tosca-simple-1.0/use-cases/block-storage-2/block-storage-2.yaml
@@ -72,4 +72,4 @@
 
     volume_id:
       description: The volume id of the block storage instance.
-      value: { get_attribute: [ my_storage, volume_id ] }
+      value: { get_property: [ my_storage, volume_id ] } # ARIA NOTE: wrong in spec
diff --git a/examples/tosca-simple-1.0/use-cases/block-storage-3/block-storage-3.yaml b/examples/tosca-simple-1.0/use-cases/block-storage-3/block-storage-3.yaml
index 3018fe9..c3f183e 100644
--- a/examples/tosca-simple-1.0/use-cases/block-storage-3/block-storage-3.yaml
+++ b/examples/tosca-simple-1.0/use-cases/block-storage-3/block-storage-3.yaml
@@ -65,4 +65,4 @@
       value: { get_attribute: [ my_server, private_address ] }
     volume_id:
       description: The volume id of the block storage instance.
-      value: { get_attribute: [ my_storage, volume_id ] }
+      value: { get_property: [ my_storage, volume_id ] } # ARIA NOTE: wrong in spec
diff --git a/examples/tosca-simple-1.0/use-cases/block-storage-4/block-storage-4.yaml b/examples/tosca-simple-1.0/use-cases/block-storage-4/block-storage-4.yaml
index 0693ddd..e2bdb9f 100644
--- a/examples/tosca-simple-1.0/use-cases/block-storage-4/block-storage-4.yaml
+++ b/examples/tosca-simple-1.0/use-cases/block-storage-4/block-storage-4.yaml
@@ -93,4 +93,4 @@
       value: { get_attribute: [ my_web_app_tier_2, private_address ] }
     volume_id:
       description: The volume id of the block storage instance.
-      value: { get_attribute: [ my_storage, volume_id ] }
+      value: { get_property: [ my_storage, volume_id ] } # ARIA NOTE: wrong in spec
diff --git a/examples/tosca-simple-1.0/use-cases/block-storage-5/block-storage-5.yaml b/examples/tosca-simple-1.0/use-cases/block-storage-5/block-storage-5.yaml
index 5f5cf71..a0c2229 100644
--- a/examples/tosca-simple-1.0/use-cases/block-storage-5/block-storage-5.yaml
+++ b/examples/tosca-simple-1.0/use-cases/block-storage-5/block-storage-5.yaml
@@ -100,10 +100,10 @@
   outputs:
     private_ip_1:
       description: The private IP address of the application's first tier.
-      value: { get_attribute: [my_web_app_tier_1, private_address] }
+      value: { get_attribute: [ my_web_app_tier_1, private_address ] }
     private_ip_2:
       description: The private IP address of the application's second tier.
-      value: { get_attribute: [my_web_app_tier_2, private_address] }
+      value: { get_attribute: [ my_web_app_tier_2, private_address ] }
     volume_id:
       description: The volume id of the block storage instance.
-      value: { get_attribute: [my_storage, volume_id] }
+      value: { get_property: [ my_storage, volume_id ] } # ARIA NOTE: wrong in spec
diff --git a/examples/tosca-simple-1.0/use-cases/block-storage-6/block-storage-6.yaml b/examples/tosca-simple-1.0/use-cases/block-storage-6/block-storage-6.yaml
index 808245b..534884a 100644
--- a/examples/tosca-simple-1.0/use-cases/block-storage-6/block-storage-6.yaml
+++ b/examples/tosca-simple-1.0/use-cases/block-storage-6/block-storage-6.yaml
@@ -96,7 +96,7 @@
       value: { get_attribute: [ my_server2, private_address ] }
     volume_id_1:
       description: The volume id of the first block storage instance.
-      value: { get_attribute: [my_storage, volume_id] }
+      value: { get_property: [ my_storage, volume_id ] } # ARIA NOTE: wrong in spec
     volume_id_2:
       description: The volume id of the second block storage instance.
-      value: { get_attribute: [ my_storage2, volume_id ] }
+      value: { get_property: [ my_storage2, volume_id ] } # ARIA NOTE: wrong in spec
diff --git a/examples/tosca-simple-1.0/use-cases/multi-tier-1/multi-tier-1.yaml b/examples/tosca-simple-1.0/use-cases/multi-tier-1/multi-tier-1.yaml
index 3485e49..50401ec 100644
--- a/examples/tosca-simple-1.0/use-cases/multi-tier-1/multi-tier-1.yaml
+++ b/examples/tosca-simple-1.0/use-cases/multi-tier-1/multi-tier-1.yaml
@@ -59,7 +59,7 @@
              implementation: scripts/nodejs/configure.sh
              inputs:
                github_url: { get_property: [ SELF, github_url ] }
-               mongodb_ip: { get_attribute: [mongo_server, private_address] }
+               mongodb_ip: { get_attribute: [ mongo_server, private_address ] }
            start: scripts/nodejs/start.sh
 
     nodejs:
@@ -90,7 +90,7 @@
           configure:
             implementation: scripts/mongodb/config.sh
             inputs:
-              mongodb_ip: { get_attribute: [mongo_server, ip_address] }
+              mongodb_ip: { get_attribute: [ mongo_server, private_address ] } # ARIA NOTE: wrong in spec
           start: scripts/mongodb/start.sh
 
     elasticsearch:
@@ -115,7 +115,7 @@
                   pre_configure_source:
                     implementation: python/logstash/configure_elasticsearch.py
                     inputs:
-                      elasticsearch_ip: { get_attribute: [elasticsearch_server, ip_address] }
+                      elasticsearch_ip: { get_attribute: [ elasticsearch_server, private_address ] } # ARIA NOTE: wrong in spec
       interfaces:
         Standard: # ARIA NOTE: wrong in spec
           create: scripts/lostash/create.sh
@@ -133,8 +133,8 @@
           configure:
             implementation: scripts/kibana/config.sh
             inputs:
-              elasticsearch_ip: { get_attribute: [ elasticsearch_server, ip_address ] }
-              kibana_ip: { get_attribute: [ kibana_server, ip_address ] }
+              elasticsearch_ip: { get_attribute: [ elasticsearch_server, private_address ] } # ARIA NOTE: wrong in spec
+              kibana_ip: { get_attribute: [ kibana_server, private_address ] } # ARIA NOTE: wrong in spec
           start: scripts/kibana/start.sh
 
     app_collectd:
@@ -155,7 +155,7 @@
           configure:
             implementation: python/collectd/config.py
             inputs:
-              logstash_ip: { get_attribute: [ logstash_server, ip_address ] }
+              logstash_ip: { get_attribute: [ logstash_server, private_address ] } # ARIA NOTE: wrong in spec
           start: scripts/collectd/start.sh
 
     app_rsyslog:
@@ -176,7 +176,7 @@
           configure:
             implementation: scripts/rsyslog/config.sh
             inputs:
-              logstash_ip: { get_attribute: [ logstash_server, ip_address ] }
+              logstash_ip: { get_attribute: [ logstash_server, private_address ] } # ARIA NOTE: wrong in spec
           start: scripts/rsyslog/start.sh
 
     app_server:
diff --git a/extensions/aria_extension_tosca/simple_v1_0/__init__.py b/extensions/aria_extension_tosca/simple_v1_0/__init__.py
index 29df362..7dcc60a 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/__init__.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/__init__.py
@@ -30,8 +30,6 @@
                     NodeType, GroupType, PolicyType)
 from .data_types import (Timestamp, Version, Range, List, Map, ScalarSize, ScalarTime,
                          ScalarFrequency)
-from .functions import (Concat, Token, GetInput, GetProperty, GetAttribute, GetOperationOutput,
-                        GetNodesOfType, GetArtifact)
 
 MODULES = (
     'modeling',
@@ -89,12 +87,4 @@
     'Map',
     'ScalarSize',
     'ScalarTime',
-    'ScalarFrequency',
-    'Concat',
-    'Token',
-    'GetInput',
-    'GetProperty',
-    'GetAttribute',
-    'GetOperationOutput',
-    'GetNodesOfType',
-    'GetArtifact')
+    'ScalarFrequency')
diff --git a/extensions/aria_extension_tosca/simple_v1_0/assignments.py b/extensions/aria_extension_tosca/simple_v1_0/assignments.py
index 9a2179a..d929ce0 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/assignments.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/assignments.py
@@ -15,7 +15,7 @@
 
 from aria.utils.collections import FrozenDict
 from aria.utils.caching import cachedmethod
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (AsIsPresentation, has_fields, allow_unknown_fields,
                                       short_form_field, primitive_field, object_field,
                                       object_dict_field, object_dict_unknown_fields,
@@ -32,7 +32,7 @@
 from .presentation.types import (convert_shorthand_to_full_type_name,
                                  get_type_by_full_or_shorthand_name)
 
-@dsl_specification('3.5.9', 'tosca-simple-1.0')
+@implements_specification('3.5.9', 'tosca-simple-1.0')
 class PropertyAssignment(AsIsPresentation):
     """
     This section defines the grammar for assigning values to named properties within TOSCA Node and
@@ -45,7 +45,7 @@
 
 @short_form_field('implementation')
 @has_fields
-@dsl_specification('3.5.13-2', 'tosca-simple-1.0')
+@implements_specification('3.5.13-2', 'tosca-simple-1.0')
 class OperationAssignment(ExtensiblePresentation):
     """
     An operation definition defines a named function or procedure that can be bound to an
@@ -105,7 +105,7 @@
 
 @allow_unknown_fields
 @has_fields
-@dsl_specification('3.5.14-2', 'tosca-simple-1.0')
+@implements_specification('3.5.14-2', 'tosca-simple-1.0')
 class InterfaceAssignment(ExtensiblePresentation):
     """
     An interface definition defines a named interface that can be associated with a Node or
@@ -200,7 +200,7 @@
 
 @short_form_field('node')
 @has_fields
-@dsl_specification('3.7.2', 'tosca-simple-1.0')
+@implements_specification('3.7.2', 'tosca-simple-1.0')
 class RequirementAssignment(ExtensiblePresentation):
     """
     A Requirement assignment allows template authors to provide either concrete names of TOSCA
@@ -297,7 +297,7 @@
 
         return None, None
 
-@dsl_specification('3.5.11', 'tosca-simple-1.0')
+@implements_specification('3.5.11', 'tosca-simple-1.0')
 class AttributeAssignment(AsIsPresentation):
     """
     This section defines the grammar for assigning values to named attributes within TOSCA Node and
@@ -309,7 +309,7 @@
     """
 
 @has_fields
-@dsl_specification('3.7.1', 'tosca-simple-1.0')
+@implements_specification('3.7.1', 'tosca-simple-1.0')
 class CapabilityAssignment(ExtensiblePresentation):
     """
     A capability assignment allows node template authors to assign values to properties and
@@ -351,7 +351,7 @@
             if capability_definition is not None else None
 
 @has_fields
-@dsl_specification('3.5.6', 'tosca-simple-1.0')
+@implements_specification('3.5.6', 'tosca-simple-1.0')
 class ArtifactAssignment(ExtensiblePresentation):
     """
     An artifact definition defines a named, typed file that can be associated with Node Type or Node
diff --git a/extensions/aria_extension_tosca/simple_v1_0/data_types.py b/extensions/aria_extension_tosca/simple_v1_0/data_types.py
index a06834c..c385f78 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/data_types.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/data_types.py
@@ -20,7 +20,7 @@
 except ImportError:
     from total_ordering import total_ordering
 
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.utils.collections import StrictDict, OrderedDict
 from aria.utils.formatting import safe_repr
 
@@ -51,7 +51,7 @@
 UTC = Timezone()
 
 @total_ordering
-@dsl_specification('timestamp', 'yaml-1.1')
+@implements_specification('timestamp', 'yaml-1.1')
 class Timestamp(object):
     '''
     TOSCA timestamps follow the YAML specification, which in turn is a variant of ISO8601.
@@ -146,7 +146,7 @@
         return '{0:g}'.format(the_datetime.microsecond / 1000000.0).lstrip('0')
 
 @total_ordering
-@dsl_specification('3.2.2', 'tosca-simple-1.0')
+@implements_specification('3.2.2', 'tosca-simple-1.0')
 class Version(object):
     """
     TOSCA supports the concept of "reuse" of type definitions, as well as template definitions which
@@ -229,7 +229,7 @@
                             return True
         return False
 
-@dsl_specification('3.2.3', 'tosca-simple-1.0')
+@implements_specification('3.2.3', 'tosca-simple-1.0')
 class Range(object):
     """
     The range type can be used to define numeric ranges with a lower and upper boundary. For
@@ -276,7 +276,7 @@
     def as_raw(self):
         return list(self.value)
 
-@dsl_specification('3.2.4', 'tosca-simple-1.0')
+@implements_specification('3.2.4', 'tosca-simple-1.0')
 class List(list):
     """
     The list type allows for specifying multiple values for a parameter of property. For example, if
@@ -309,7 +309,7 @@
     def as_raw(self):
         return list(self)
 
-@dsl_specification('3.2.5', 'tosca-simple-1.0')
+@implements_specification('3.2.5', 'tosca-simple-1.0')
 class Map(StrictDict):
     """
     The map type allows for specifying multiple values for a parameter of property as a map. In
@@ -349,7 +349,7 @@
         return OrderedDict(self)
 
 @total_ordering
-@dsl_specification('3.2.6', 'tosca-simple-1.0')
+@implements_specification('3.2.6', 'tosca-simple-1.0')
 class Scalar(object):
     """
     The scalar-unit type can be used to define scalar values along with a unit from the list of
@@ -416,7 +416,7 @@
             value = self.TYPE(scalar) # pylint: disable=no-member
         return self.value < value
 
-@dsl_specification('3.2.6.4', 'tosca-simple-1.0')
+@implements_specification('3.2.6.4', 'tosca-simple-1.0')
 class ScalarSize(Scalar):
     """
     Integer scalar for counting bytes.
@@ -444,7 +444,7 @@
     TYPE = int
     UNIT = 'bytes'
 
-@dsl_specification('3.2.6.5', 'tosca-simple-1.0')
+@implements_specification('3.2.6.5', 'tosca-simple-1.0')
 class ScalarTime(Scalar):
     """
     Floating point scalar for counting seconds.
@@ -469,7 +469,7 @@
     TYPE = float
     UNIT = 'seconds'
 
-@dsl_specification('3.2.6.6', 'tosca-simple-1.0')
+@implements_specification('3.2.6.6', 'tosca-simple-1.0')
 class ScalarFrequency(Scalar):
     """
     Floating point scalar for counting cycles per second (Hz).
diff --git a/extensions/aria_extension_tosca/simple_v1_0/definitions.py b/extensions/aria_extension_tosca/simple_v1_0/definitions.py
index b60a797..8564249 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/definitions.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/definitions.py
@@ -15,7 +15,7 @@
 
 from aria.utils.collections import FrozenDict
 from aria.utils.caching import cachedmethod
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (has_fields, short_form_field, allow_unknown_fields,
                                       primitive_field, primitive_list_field, object_field,
                                       object_list_field, object_dict_field,
@@ -35,7 +35,7 @@
                                   get_and_override_operation_definitions_from_type)
 
 @has_fields
-@dsl_specification('3.5.8', 'tosca-simple-1.0')
+@implements_specification('3.5.8', 'tosca-simple-1.0')
 class PropertyDefinition(ExtensiblePresentation):
     """
     A property definition defines a named, typed value and related data that can be associated with
@@ -86,7 +86,7 @@
 
     @primitive_field(str, default='supported', allowed=('supported', 'unsupported', 'experimental',
                                                         'deprecated'))
-    @dsl_specification(section='3.5.8.3', spec='tosca-simple-1.0')
+    @implements_specification(section='3.5.8.3', spec='tosca-simple-1.0')
     def status(self):
         """
         The optional status of the property relative to the specification or implementation.
@@ -121,7 +121,7 @@
         return get_property_constraints(context, self)
 
 @has_fields
-@dsl_specification('3.5.10', 'tosca-simple-1.0')
+@implements_specification('3.5.10', 'tosca-simple-1.0')
 class AttributeDefinition(ExtensiblePresentation):
     """
     An attribute definition defines a named, typed value that can be associated with an entity
@@ -190,7 +190,7 @@
         return get_data_type(context, self, 'type')
 
 @has_fields
-@dsl_specification('3.5.12', 'tosca-simple-1.0')
+@implements_specification('3.5.12', 'tosca-simple-1.0')
 class ParameterDefinition(PropertyDefinition):
     """
     A parameter definition is essentially a TOSCA property definition; however, it also allows a
@@ -225,7 +225,7 @@
 
 @short_form_field('implementation')
 @has_fields
-@dsl_specification('3.5.13-1', 'tosca-simple-1.0')
+@implements_specification('3.5.13-1', 'tosca-simple-1.0')
 class OperationDefinition(ExtensiblePresentation):
     """
     An operation definition defines a named function or procedure that can be bound to an
@@ -266,7 +266,7 @@
 
 @allow_unknown_fields
 @has_fields
-@dsl_specification('3.5.14-1', 'tosca-simple-1.0')
+@implements_specification('3.5.14-1', 'tosca-simple-1.0')
 class InterfaceDefinition(ExtensiblePresentation):
     """
     An interface definition defines a named interface that can be associated with a Node or
@@ -352,7 +352,7 @@
 
 @short_form_field('capability')
 @has_fields
-@dsl_specification('3.6.2', 'tosca-simple-1.0')
+@implements_specification('3.6.2', 'tosca-simple-1.0')
 class RequirementDefinition(ExtensiblePresentation):
     """
     The Requirement definition describes a named requirement (dependencies) of a TOSCA Node Type or
@@ -418,7 +418,7 @@
 
 @short_form_field('type')
 @has_fields
-@dsl_specification('3.6.1', 'tosca-simple-1.0')
+@implements_specification('3.6.1', 'tosca-simple-1.0')
 class CapabilityDefinition(ExtensiblePresentation):
     """
     A capability definition defines a named, typed set of data that can be associated with Node Type
diff --git a/extensions/aria_extension_tosca/simple_v1_0/filters.py b/extensions/aria_extension_tosca/simple_v1_0/filters.py
index 617ce7a..838b505 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/filters.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/filters.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 from aria.utils.caching import cachedmethod
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (has_fields, object_sequenced_list_field, field_validator)
 
 from .misc import ConstraintClause
@@ -45,7 +45,7 @@
         return None
 
 @has_fields
-@dsl_specification('3.5.4', 'tosca-simple-1.0')
+@implements_specification('3.5.4', 'tosca-simple-1.0')
 class NodeFilter(ExtensiblePresentation):
     """
     A node filter definition defines criteria for selection of a TOSCA Node Template based upon the
@@ -58,7 +58,7 @@
 
     @field_validator(node_filter_properties_validator)
     @object_sequenced_list_field(ConstraintClause)
-    @dsl_specification('3.5.3', 'tosca-simple-1.0')
+    @implements_specification('3.5.3', 'tosca-simple-1.0')
     def properties(self):
         """
         An optional sequenced list of property filters that would be used to select (filter)
diff --git a/extensions/aria_extension_tosca/simple_v1_0/misc.py b/extensions/aria_extension_tosca/simple_v1_0/misc.py
index 42fc1ad..74eba18 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/misc.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/misc.py
@@ -16,7 +16,7 @@
 from aria.utils.caching import cachedmethod
 from aria.utils.console import puts
 from aria.utils.formatting import as_raw
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (AsIsPresentation, has_fields, allow_unknown_fields,
                                       short_form_field, primitive_field, primitive_list_field,
                                       primitive_dict_unknown_fields, object_field,
@@ -36,7 +36,7 @@
 from .presentation.types import (convert_shorthand_to_full_type_name,
                                  get_type_by_full_or_shorthand_name)
 
-@dsl_specification('3.5.1', 'tosca-simple-1.0')
+@implements_specification('3.5.1', 'tosca-simple-1.0')
 class Description(AsIsPresentation):
     """
     See the `TOSCA Simple Profile v1.0 cos01 specification <http://docs.oasis-open.org/tosca
@@ -53,10 +53,10 @@
 
 @allow_unknown_fields
 @has_fields
-@dsl_specification('3.9.3.2', 'tosca-simple-1.0')
+@implements_specification('3.9.3.2', 'tosca-simple-1.0')
 class MetaData(ExtensiblePresentation):
     @primitive_field(str)
-    @dsl_specification('3.9.3.3', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.3', 'tosca-simple-1.0')
     def template_name(self):
         """
         This optional metadata keyname can be used to declare the name of service template as a
@@ -64,7 +64,7 @@
         """
 
     @primitive_field(str)
-    @dsl_specification('3.9.3.4', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.4', 'tosca-simple-1.0')
     def template_author(self):
         """
         This optional metadata keyname can be used to declare the author(s) of the service template
@@ -72,7 +72,7 @@
         """
 
     @primitive_field(str)
-    @dsl_specification('3.9.3.5', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.5', 'tosca-simple-1.0')
     def template_version(self):
         """
         This optional metadata keyname can be used to declare a domain specific version of the
@@ -87,7 +87,7 @@
 
 @short_form_field('url')
 @has_fields
-@dsl_specification('3.5.5', 'tosca-simple-1.0')
+@implements_specification('3.5.5', 'tosca-simple-1.0')
 class Repository(ExtensiblePresentation):
     """
     A repository definition defines a named external repository which contains deployment and
@@ -128,7 +128,7 @@
 
 @short_form_field('file')
 @has_fields
-@dsl_specification('3.5.7', 'tosca-simple-1.0')
+@implements_specification('3.5.7', 'tosca-simple-1.0')
 class Import(ExtensiblePresentation):
     """
     An import definition is used within a TOSCA Service Template to locate and uniquely name another
@@ -177,7 +177,7 @@
         """
 
 @has_fields
-@dsl_specification('3.5.2', 'tosca-simple-1.0')
+@implements_specification('3.5.2-1', 'tosca-simple-1.0')
 class ConstraintClause(ExtensiblePresentation):
     """
     A constraint clause defines an operation along with one or more compatible values that can be
@@ -376,7 +376,7 @@
         validate_subtitution_mappings_capability(context, self)
 
 @has_fields
-@dsl_specification('2.10', 'tosca-simple-1.0')
+@implements_specification('2.10', 'tosca-simple-1.0')
 class SubstitutionMappings(ExtensiblePresentation):
     @field_validator(type_validator('node type', convert_shorthand_to_full_type_name, 'node_types'))
     @primitive_field(str, required=True)
diff --git a/extensions/aria_extension_tosca/simple_v1_0/modeling/__init__.py b/extensions/aria_extension_tosca/simple_v1_0/modeling/__init__.py
index 3bda7e2..99389e4 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/modeling/__init__.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/modeling/__init__.py
@@ -34,6 +34,8 @@
                                   SubstitutionTemplateMapping, InterfaceTemplate, OperationTemplate,
                                   ArtifactTemplate, Metadata, Parameter, PluginSpecification)
 
+from .constraints import (Equal, GreaterThan, GreaterOrEqual, LessThan, LessOrEqual, InRange,
+                          ValidValues, Length, MinLength, MaxLength, Pattern)
 from ..data_types import coerce_value
 
 
@@ -166,6 +168,8 @@
 
     create_parameter_models_from_values(model.properties,
                                         node_template._get_property_values(context))
+    create_parameter_models_from_values(model.attributes,
+                                        node_template._get_attribute_default_values(context))
     create_interface_template_models(context, service_template, model.interface_templates,
                                      node_template._get_interfaces(context))
 
@@ -181,10 +185,10 @@
             model.capability_templates[capability_name] = \
                 create_capability_template_model(context, service_template, capability)
 
-    if model.target_node_template_constraints:
+    if node_template.node_filter:
         model.target_node_template_constraints = []
-        create_node_filter_constraint_lambdas(context, node_template.node_filter,
-                                              model.target_node_template_constraints)
+        create_node_filter_constraints(context, node_template.node_filter,
+                                       model.target_node_template_constraints)
 
     return model
 
@@ -273,10 +277,10 @@
 
     model = RequirementTemplate(**model)
 
-    if model.target_node_template_constraints:
+    if requirement.node_filter:
         model.target_node_template_constraints = []
-        create_node_filter_constraint_lambdas(context, requirement.node_filter,
-                                              model.target_node_template_constraints)
+        create_node_filter_constraints(context, requirement.node_filter,
+                                       model.target_node_template_constraints)
 
     relationship = requirement.relationship
     if relationship is not None:
@@ -348,7 +352,7 @@
     inputs = interface.inputs
     if inputs:
         for input_name, the_input in inputs.iteritems():
-            model.inputs[input_name] = Parameter(name=input_name,
+            model.inputs[input_name] = Parameter(name=input_name, # pylint: disable=unexpected-keyword-arg
                                                  type_name=the_input.value.type,
                                                  value=the_input.value.value,
                                                  description=the_input.value.description)
@@ -395,7 +399,7 @@
     inputs = operation.inputs
     if inputs:
         for input_name, the_input in inputs.iteritems():
-            model.inputs[input_name] = Parameter(name=input_name,
+            model.inputs[input_name] = Parameter(name=input_name, # pylint: disable=unexpected-keyword-arg
                                                  type_name=the_input.value.type,
                                                  value=the_input.value.value,
                                                  description=the_input.value.description)
@@ -491,7 +495,7 @@
         elif prop_name == 'dependencies':
             model.dependencies = prop.value
         else:
-            model.inputs[prop_name] = Parameter(name=prop_name,
+            model.inputs[prop_name] = Parameter(name=prop_name, # pylint: disable=unexpected-keyword-arg
                                                 type_name=prop.type,
                                                 value=prop.value,
                                                 description=prop.description)
@@ -536,7 +540,7 @@
 def create_parameter_models_from_values(properties, source_properties):
     if source_properties:
         for property_name, prop in source_properties.iteritems():
-            properties[property_name] = Parameter(name=property_name,
+            properties[property_name] = Parameter(name=property_name, # pylint: disable=unexpected-keyword-arg
                                                   type_name=prop.type,
                                                   value=prop.value,
                                                   description=prop.description)
@@ -545,7 +549,7 @@
 def create_parameter_models_from_assignments(properties, source_properties):
     if source_properties:
         for property_name, prop in source_properties.iteritems():
-            properties[property_name] = Parameter(name=property_name,
+            properties[property_name] = Parameter(name=property_name, # pylint: disable=unexpected-keyword-arg
                                                   type_name=prop.value.type,
                                                   value=prop.value.value,
                                                   description=prop.value.description)
@@ -559,17 +563,13 @@
                 interfaces[interface_name] = interface
 
 
-def create_node_filter_constraint_lambdas(context, node_filter, target_node_template_constraints):
-    if node_filter is None:
-        return
-
+def create_node_filter_constraints(context, node_filter, target_node_template_constraints):
     properties = node_filter.properties
     if properties is not None:
         for property_name, constraint_clause in properties:
-            func = create_constraint_clause_lambda(context, node_filter, constraint_clause,
-                                                   property_name, None)
-            if func is not None:
-                target_node_template_constraints.append(func)
+            constraint = create_constraint(context, node_filter, constraint_clause, property_name,
+                                           None)
+            target_node_template_constraints.append(constraint)
 
     capabilities = node_filter.capabilities
     if capabilities is not None:
@@ -577,129 +577,64 @@
             properties = capability.properties
             if properties is not None:
                 for property_name, constraint_clause in properties:
-                    func = create_constraint_clause_lambda(context, node_filter, constraint_clause,
-                                                           property_name, capability_name)
-                    if func is not None:
-                        target_node_template_constraints.append(func)
+                    constraint = create_constraint(context, node_filter, constraint_clause,
+                                                   property_name, capability_name)
+                    target_node_template_constraints.append(constraint)
 
 
-def create_constraint_clause_lambda(context, node_filter, constraint_clause, property_name, # pylint: disable=too-many-return-statements
-                                    capability_name):
+def create_constraint(context, node_filter, constraint_clause, property_name, capability_name): # pylint: disable=too-many-return-statements
     constraint_key = constraint_clause._raw.keys()[0]
+
     the_type = constraint_clause._get_type(context)
 
-    def coerce_constraint(constraint, container):
-        constraint = coerce_value(context, node_filter, the_type, None, None, constraint,
-                                  constraint_key) if the_type is not None else constraint
-        if hasattr(constraint, '_evaluate'):
-            constraint = constraint._evaluate(context, container)
-        return constraint
+    def coerce_constraint(constraint):
+        if the_type is not None:
+            return coerce_value(context, node_filter, the_type, None, None, constraint,
+                                constraint_key)
+        else:
+            return constraint
 
-    def get_value(node_type):
-        if capability_name is not None:
-            capability = node_type.capability_templates.get(capability_name)
-            prop = capability.properties.get(property_name) if capability is not None else None
-            return prop.value if prop is not None else None
-        value = node_type.properties.get(property_name)
-        return value.value if value is not None else None
+    def coerce_constraints(constraints):
+        if the_type is not None:
+            return tuple(coerce_constraint(constraint) for constraint in constraints)
+        else:
+            return constraints
 
     if constraint_key == 'equal':
-        def equal(node_type, container):
-            constraint = coerce_constraint(constraint_clause.equal, container)
-            value = get_value(node_type)
-            return value == constraint
-
-        return equal
-
+        return Equal(property_name, capability_name,
+                     coerce_constraint(constraint_clause.equal))
     elif constraint_key == 'greater_than':
-        def greater_than(node_type, container):
-            constraint = coerce_constraint(constraint_clause.greater_than, container)
-            value = get_value(node_type)
-            return value > constraint
-
-        return greater_than
-
+        return GreaterThan(property_name, capability_name,
+                           coerce_constraint(constraint_clause.greater_than))
     elif constraint_key == 'greater_or_equal':
-        def greater_or_equal(node_type, container):
-            constraint = coerce_constraint(constraint_clause.greater_or_equal, container)
-            value = get_value(node_type)
-            return value >= constraint
-
-        return greater_or_equal
-
+        return GreaterOrEqual(property_name, capability_name,
+                              coerce_constraint(constraint_clause.greater_or_equal))
     elif constraint_key == 'less_than':
-        def less_than(node_type, container):
-            constraint = coerce_constraint(constraint_clause.less_than, container)
-            value = get_value(node_type)
-            return value < constraint
-
-        return less_than
-
+        return LessThan(property_name, capability_name,
+                        coerce_constraint(constraint_clause.less_than))
     elif constraint_key == 'less_or_equal':
-        def less_or_equal(node_type, container):
-            constraint = coerce_constraint(constraint_clause.less_or_equal, container)
-            value = get_value(node_type)
-            return value <= constraint
-
-        return less_or_equal
-
+        return LessOrEqual(property_name, capability_name,
+                           coerce_constraint(constraint_clause.less_or_equal))
     elif constraint_key == 'in_range':
-        def in_range(node_type, container):
-            lower, upper = constraint_clause.in_range
-            lower, upper = coerce_constraint(lower, container), coerce_constraint(upper, container)
-            value = get_value(node_type)
-            if value < lower:
-                return False
-            if (upper != 'UNBOUNDED') and (value > upper):
-                return False
-            return True
-
-        return in_range
-
+        return InRange(property_name, capability_name,
+                       coerce_constraints(constraint_clause.in_range))
     elif constraint_key == 'valid_values':
-        def valid_values(node_type, container):
-            constraint = tuple(coerce_constraint(v, container)
-                               for v in constraint_clause.valid_values)
-            value = get_value(node_type)
-            return value in constraint
-
-        return valid_values
-
+        return ValidValues(property_name, capability_name,
+                           coerce_constraints(constraint_clause.valid_values))
     elif constraint_key == 'length':
-        def length(node_type, container): # pylint: disable=unused-argument
-            constraint = constraint_clause.length
-            value = get_value(node_type)
-            return len(value) == constraint
-
-        return length
-
+        return Length(property_name, capability_name,
+                      coerce_constraint(constraint_clause.length))
     elif constraint_key == 'min_length':
-        def min_length(node_type, container): # pylint: disable=unused-argument
-            constraint = constraint_clause.min_length
-            value = get_value(node_type)
-            return len(value) >= constraint
-
-        return min_length
-
+        return MinLength(property_name, capability_name,
+                         coerce_constraint(constraint_clause.min_length))
     elif constraint_key == 'max_length':
-        def max_length(node_type, container): # pylint: disable=unused-argument
-            constraint = constraint_clause.max_length
-            value = get_value(node_type)
-            return len(value) >= constraint
-
-        return max_length
-
+        return MaxLength(property_name, capability_name,
+                         coerce_constraint(constraint_clause.max_length))
     elif constraint_key == 'pattern':
-        def pattern(node_type, container): # pylint: disable=unused-argument
-            constraint = constraint_clause.pattern
-            # Note: the TOSCA 1.0 spec does not specify the regular expression grammar, so we will
-            # just use Python's
-            value = node_type.properties.get(property_name)
-            return re.match(constraint, str(value)) is not None
-
-        return pattern
-
-    return None
+        return Pattern(property_name, capability_name,
+                       coerce_constraint(constraint_clause.pattern))
+    else:
+        raise ValueError('malformed node_filter: {0}'.format(constraint_key))
 
 
 def split_prefix(string):
diff --git a/extensions/aria_extension_tosca/simple_v1_0/modeling/constraints.py b/extensions/aria_extension_tosca/simple_v1_0/modeling/constraints.py
new file mode 100644
index 0000000..7c99eab
--- /dev/null
+++ b/extensions/aria_extension_tosca/simple_v1_0/modeling/constraints.py
@@ -0,0 +1,144 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import re
+
+from aria.modeling.contraints import NodeTemplateConstraint
+from aria.modeling.utils import NodeTemplateContainerHolder
+from aria.modeling.functions import evaluate
+from aria.parser import implements_specification
+
+
+@implements_specification('3.5.2-2', 'tosca-simple-1.0')
+class EvaluatingNodeTemplateConstraint(NodeTemplateConstraint):
+    """
+    A version of :class:`NodeTemplateConstraint` with boilerplate initialization for TOSCA
+    constraints.
+    """
+
+    def __init__(self, property_name, capability_name, constraint, as_list=False):
+        self.property_name = property_name
+        self.capability_name = capability_name
+        self.constraint = constraint
+        self.as_list = as_list
+
+    def matches(self, source_node_template, target_node_template):
+        # TOSCA node template constraints can refer to either capability properties or node
+        # template properties
+        if self.capability_name is not None:
+            # Capability property
+            capability = target_node_template.capability_templates.get(self.capability_name)
+            value = capability.properties.get(self.property_name) \
+                if capability is not None else None # Parameter
+        else:
+            # Node template property
+            value = target_node_template.properties.get(self.property_name) # Parameter
+
+        value = value.value if value is not None else None
+
+        container_holder = NodeTemplateContainerHolder(source_node_template)
+
+        if self.as_list:
+            constraints = []
+            for constraint in self.constraint:
+                evaluation = evaluate(constraint, container_holder)
+                if evaluation is not None:
+                    constraints.append(evaluation.value)
+                else:
+                    constraints.append(constraint)
+            constraint = constraints
+        else:
+            evaluation = evaluate(self.constraint, container_holder)
+            if evaluation is not None:
+                constraint = evaluation.value
+            else:
+                constraint = self.constraint
+
+        return self.matches_evaluated(value, constraint)
+
+    def matches_evaluated(self, value, constraint):
+        raise NotImplementedError
+
+
+class Equal(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return value == constraint
+
+
+class GreaterThan(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return value > constraint
+
+
+class GreaterOrEqual(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return value >= constraint
+
+
+class LessThan(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return value < constraint
+
+
+class LessOrEqual(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return value <= constraint
+
+
+class InRange(EvaluatingNodeTemplateConstraint):
+    def __init__(self, property_name, capability_name, constraint):
+        super(InRange, self).__init__(property_name, capability_name, constraint, as_list=True)
+
+    def matches_evaluated(self, value, constraints):
+        lower, upper = constraints
+        if value < lower:
+            return False
+        if (upper != 'UNBOUNDED') and (value > upper):
+            return False
+        return True
+
+
+class ValidValues(EvaluatingNodeTemplateConstraint):
+    def __init__(self, property_name, capability_name, constraint):
+        super(ValidValues, self).__init__(property_name, capability_name, constraint, as_list=True)
+
+    def matches_evaluated(self, value, constraints):
+        return value in constraints
+
+
+class Length(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return len(value) == constraint
+
+
+class MinLength(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return len(value) >= constraint
+
+
+class MaxLength(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        return len(value) <= constraint
+
+
+class Pattern(EvaluatingNodeTemplateConstraint):
+    def matches_evaluated(self, value, constraint):
+        # From TOSCA 1.0 3.5.2.1:
+        #
+        # "Note: Future drafts of this specification will detail the use of regular expressions and
+        # reference an appropriate standardized grammar."
+        #
+        # So we will just use Python's.
+        return re.match(constraint, unicode(value)) is not None
diff --git a/extensions/aria_extension_tosca/simple_v1_0/modeling/data_types.py b/extensions/aria_extension_tosca/simple_v1_0/modeling/data_types.py
index 99dcfea..3952785 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/modeling/data_types.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/modeling/data_types.py
@@ -16,13 +16,14 @@
 import re
 
 from aria.utils.collections import OrderedDict
-from aria.utils.formatting import full_type_name, safe_repr
+from aria.utils.formatting import safe_repr
+from aria.utils.type import full_type_name
 from aria.utils.imports import import_fullname
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (get_locator, validate_primitive)
 from aria.parser.validation import Issue
 
-from ..functions import get_function
+from .functions import get_function
 from ..presentation.types import get_type_by_full_or_shorthand_name
 
 #
@@ -295,8 +296,12 @@
     elif constraint_key == 'pattern':
         constraint = constraint_clause.pattern
         try:
-            # Note: the TOSCA 1.0 spec does not specify the regular expression grammar, so we will
-            # just use Python's
+            # From TOSCA 1.0 3.5.2.1:
+            #
+            # "Note: Future drafts of this specification will detail the use of regular expressions
+            # and reference an appropriate standardized grammar."
+            #
+            # So we will just use Python's.
             if re.match(constraint, str(value)) is None:
                 report('does not match regular expression', constraint)
                 return False
@@ -327,20 +332,20 @@
 
 PRIMITIVE_DATA_TYPES = {
     # YAML 1.2:
-    'tag:yaml.org,2002:str': str,
+    'tag:yaml.org,2002:str': unicode,
     'tag:yaml.org,2002:integer': int,
     'tag:yaml.org,2002:float': float,
     'tag:yaml.org,2002:bool': bool,
     'tag:yaml.org,2002:null': None.__class__,
 
     # TOSCA aliases:
-    'string': str,
+    'string': unicode,
     'integer': int,
     'float': float,
     'boolean': bool,
     'null': None.__class__}
 
-@dsl_specification('3.2.1', 'tosca-simple-1.0')
+@implements_specification('3.2.1-3', 'tosca-simple-1.0')
 def get_primitive_data_type(type_name):
     """
     Many of the types we use in this profile are built-in types from the YAML 1.2 specification
@@ -371,6 +376,8 @@
     If the extension is present, we will delegate to that hook.
     """
 
+    # TODO: should support models as well as presentations
+
     is_function, func = get_function(context, presentation, value)
     if is_function:
         return func
diff --git a/extensions/aria_extension_tosca/simple_v1_0/functions.py b/extensions/aria_extension_tosca/simple_v1_0/modeling/functions.py
similarity index 63%
rename from extensions/aria_extension_tosca/simple_v1_0/functions.py
rename to extensions/aria_extension_tosca/simple_v1_0/modeling/functions.py
index 2f77420..7089ed9 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/functions.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/modeling/functions.py
@@ -14,20 +14,24 @@
 # limitations under the License.
 
 from cStringIO import StringIO
+import re
 
 from aria.utils.collections import FrozenList
-from aria.utils.formatting import as_raw, safe_repr
-from aria.parser import dsl_specification
+from aria.utils.formatting import (as_raw, safe_repr)
+from aria.utils.type import full_type_name
+from aria.parser import implements_specification
 from aria.parser.exceptions import InvalidValueError
 from aria.parser.validation import Issue
 from aria.modeling.exceptions import CannotEvaluateFunctionException
-from aria.modeling.functions import Function
+from aria.modeling.models import (Node, NodeTemplate, Relationship, RelationshipTemplate)
+from aria.modeling.functions import (Function, Evaluation)
+
 
 #
 # Intrinsic
 #
 
-@dsl_specification('4.3.1', 'tosca-simple-1.0')
+@implements_specification('4.3.1', 'tosca-simple-1.0')
 class Concat(Function):
     """
     The :code:`concat` function is used to concatenate two or more string values within a TOSCA
@@ -39,8 +43,8 @@
 
         if not isinstance(argument, list):
             raise InvalidValueError(
-                'function "concat" argument must be a list of string expressions: %s'
-                % safe_repr(argument),
+                'function "concat" argument must be a list of string expressions: {0}'
+                .format(safe_repr(argument)),
                 locator=self.locator)
 
         string_expressions = []
@@ -58,15 +62,18 @@
             string_expressions.append(string_expression)
         return {'concat': string_expressions}
 
-    def _evaluate(self, context, container):
+    def __evaluate__(self, container_holder):
+        final = True
         value = StringIO()
         for e in self.string_expressions:
-            if hasattr(e, '_evaluate'):
-                e = e._evaluate(context, container)
-            value.write(str(e))
-        return value.getvalue()
+            e, final = evaluate(e, final, container_holder)
+            if e is not None:
+                value.write(unicode(e))
+        value = value.getvalue()
+        return Evaluation(value, final)
 
-@dsl_specification('4.3.2', 'tosca-simple-1.0')
+
+@implements_specification('4.3.2', 'tosca-simple-1.0')
 class Token(Function):
     """
     The :code:`token` function is used within a TOSCA service template on a string to parse out
@@ -77,8 +84,8 @@
         self.locator = presentation._locator
 
         if (not isinstance(argument, list)) or (len(argument) != 3):
-            raise InvalidValueError('function "token" argument must be a list of 3 parameters: %s'
-                                    % safe_repr(argument),
+            raise InvalidValueError('function "token" argument must be a list of 3 parameters: {0}'
+                                    .format(safe_repr(argument)),
                                     locator=self.locator)
 
         self.string_with_tokens = parse_string_expression(context, presentation, 'token', 0,
@@ -94,21 +101,30 @@
         string_with_tokens = self.string_with_tokens
         if hasattr(string_with_tokens, 'as_raw'):
             string_with_tokens = as_raw(string_with_tokens)
-        string_of_token_chars = self.string_with_tokens
+        string_of_token_chars = self.string_of_token_chars
         if hasattr(string_of_token_chars, 'as_raw'):
             string_of_token_chars = as_raw(string_of_token_chars)
         return {'token': [string_with_tokens, string_of_token_chars, self.substring_index]}
 
-    def _evaluate(self, context, container):
-        string_with_tokens = self.string_with_tokens
-        if hasattr(string_with_tokens, '_evaluate'):
-            string_with_tokens = string_with_tokens._evaluate(context, container) # pylint: disable=no-member
+    def __evaluate__(self, container_holder):
+        final = True
+        string_with_tokens, final = evaluate(self.string_with_tokens, final, container_holder)
+        string_of_token_chars, final = evaluate(self.string_of_token_chars, final, container_holder)
+
+        if string_of_token_chars:
+            regex = '[' + ''.join(re.escape(c) for c in string_of_token_chars) + ']'
+            split = re.split(regex, string_with_tokens)
+            if self.substring_index < len(split):
+                return Evaluation(split[self.substring_index], final)
+
+        raise CannotEvaluateFunctionException()
+
 
 #
 # Property
 #
 
-@dsl_specification('4.4.1', 'tosca-simple-1.0')
+@implements_specification('4.4.1', 'tosca-simple-1.0')
 class GetInput(Function):
     """
     The :code:`get_input` function is used to retrieve the values of properties declared within the
@@ -127,23 +143,31 @@
                                                            'inputs', self.input_property_name)
             if the_input is None:
                 raise InvalidValueError(
-                    'function "get_input" argument is not a valid input name: %s'
-                    % safe_repr(argument),
+                    'function "get_input" argument is not a valid input name: {0}'
+                    .format(safe_repr(argument)),
                     locator=self.locator)
 
     @property
     def as_raw(self):
         return {'get_input': as_raw(self.input_property_name)}
 
-    def _evaluate(self, context, container): # pylint: disable=unused-argument
-        if not context.modeling.instance:
+    def __evaluate__(self, container_holder):
+        service = container_holder.service
+        if service is None:
             raise CannotEvaluateFunctionException()
-        the_input = context.modeling.instance.inputs.get(
-            self.input_property_name,
-            context.modeling.template.inputs.get(self.input_property_name))
-        return as_raw(the_input.value) if the_input is not None else None
 
-@dsl_specification('4.4.2', 'tosca-simple-1.0')
+        value = service.inputs.get(self.input_property_name)
+        if value is not None:
+            value = value.value
+            return Evaluation(value, False) # We never return final evaluations!
+
+        raise InvalidValueError(
+            'function "get_input" argument is not a valid input name: {0}'
+            .format(safe_repr(self.input_property_name)),
+            locator=self.locator)
+
+
+@implements_specification('4.4.2', 'tosca-simple-1.0')
 class GetProperty(Function):
     """
     The :code:`get_property` function is used to retrieve property values between modelable entities
@@ -156,8 +180,7 @@
         if (not isinstance(argument, list)) or (len(argument) < 2):
             raise InvalidValueError(
                 'function "get_property" argument must be a list of at least 2 string expressions: '
-                '%s'
-                % safe_repr(argument),
+                '{0}'.format(safe_repr(argument)),
                 locator=self.locator)
 
         self.modelable_entity_name = parse_modelable_entity_name(context, presentation,
@@ -169,8 +192,8 @@
     def as_raw(self):
         return {'get_property': [self.modelable_entity_name] + self.nested_property_name_or_index}
 
-    def _evaluate(self, context, container):
-        modelable_entities = get_modelable_entities(context, container, self.locator,
+    def __evaluate__(self, container_holder):
+        modelable_entities = get_modelable_entities(container_holder, 'get_property', self.locator,
                                                     self.modelable_entity_name)
         req_or_cap_name = self.nested_property_name_or_index[0]
 
@@ -197,31 +220,22 @@
                 properties = modelable_entity.properties
                 nested_property_name_or_index = self.nested_property_name_or_index
 
-            if properties:
-                found = True
-                value = properties
-                for name in nested_property_name_or_index:
-                    if (isinstance(value, dict) and (name in value)) \
-                        or (isinstance(value, list) and name < len(list)):
-                        value = value[name]
-                        if hasattr(value, '_evaluate'):
-                            value = value._evaluate(context, modelable_entity)
-                    else:
-                        found = False
-                        break
-                if found:
-                    return as_raw(value)
+            evaluation = get_modelable_entity_parameter(modelable_entity, properties,
+                                                        nested_property_name_or_index)
+            if evaluation is not None:
+                return evaluation
 
         raise InvalidValueError(
-            'function "get_property" could not find "%s" in modelable entity "%s"' \
-            % ('.'.join(self.nested_property_name_or_index), self.modelable_entity_name),
+            'function "get_property" could not find "{0}" in modelable entity "{1}"'
+            .format('.'.join(self.nested_property_name_or_index), self.modelable_entity_name),
             locator=self.locator)
 
+
 #
 # Attribute
 #
 
-@dsl_specification('4.5.1', 'tosca-simple-1.0')
+@implements_specification('4.5.1', 'tosca-simple-1.0')
 class GetAttribute(Function):
     """
     The :code:`get_attribute` function is used to retrieve the values of named attributes declared
@@ -234,27 +248,41 @@
         if (not isinstance(argument, list)) or (len(argument) < 2):
             raise InvalidValueError(
                 'function "get_attribute" argument must be a list of at least 2 string expressions:'
-                ' %s'
-                % safe_repr(argument),
+                ' {0}'.format(safe_repr(argument)),
                 locator=self.locator)
 
         self.modelable_entity_name = parse_modelable_entity_name(context, presentation,
                                                                  'get_attribute', 0, argument[0])
         # The first of these will be tried as a req-or-cap name:
-        self.nested_property_name_or_index = argument[1:]
+        self.nested_attribute_name_or_index = argument[1:]
 
     @property
     def as_raw(self):
-        return {'get_attribute': [self.modelable_entity_name] + self.nested_property_name_or_index}
+        return {'get_attribute': [self.modelable_entity_name] + self.nested_attribute_name_or_index}
 
-    def _evaluate(self, context, container): # pylint: disable=no-self-use,unused-argument
-        raise CannotEvaluateFunctionException()
+    def __evaluate__(self, container_holder):
+        modelable_entities = get_modelable_entities(container_holder, 'get_attribute', self.locator,
+                                                    self.modelable_entity_name)
+        for modelable_entity in modelable_entities:
+            attributes = modelable_entity.attributes
+            nested_attribute_name_or_index = self.nested_attribute_name_or_index
+            evaluation = get_modelable_entity_parameter(modelable_entity, attributes,
+                                                        nested_attribute_name_or_index)
+            if evaluation is not None:
+                evaluation.final = False # We never return final evaluations!
+                return evaluation
+
+        raise InvalidValueError(
+            'function "get_attribute" could not find "{0}" in modelable entity "{1}"'
+            .format('.'.join(self.nested_attribute_name_or_index), self.modelable_entity_name),
+            locator=self.locator)
+
 
 #
 # Operation
 #
 
-@dsl_specification('4.6.1', 'tosca-simple-1.0')  # pylint: disable=abstract-method
+@implements_specification('4.6.1', 'tosca-simple-1.0') # pylint: disable=abstract-method
 class GetOperationOutput(Function):
     """
     The :code:`get_operation_output` function is used to retrieve the values of variables exposed /
@@ -266,8 +294,8 @@
 
         if (not isinstance(argument, list)) or (len(argument) != 4):
             raise InvalidValueError(
-                'function "get_operation_output" argument must be a list of 4 parameters: %s'
-                % safe_repr(argument),
+                'function "get_operation_output" argument must be a list of 4 parameters: {0}'
+                .format(safe_repr(argument)),
                 locator=self.locator)
 
         self.modelable_entity_name = parse_string_expression(context, presentation,
@@ -295,11 +323,12 @@
         return {'get_operation_output': [self.modelable_entity_name, interface_name, operation_name,
                                          output_variable_name]}
 
+
 #
 # Navigation
 #
 
-@dsl_specification('4.7.1', 'tosca-simple-1.0')
+@implements_specification('4.7.1', 'tosca-simple-1.0')
 class GetNodesOfType(Function):
     """
     The :code:`get_nodes_of_type` function can be used to retrieve a list of all known instances of
@@ -316,8 +345,8 @@
             node_types = context.presentation.get('service_template', 'node_types')
             if (node_types is None) or (self.node_type_name not in node_types):
                 raise InvalidValueError(
-                    'function "get_nodes_of_type" argument is not a valid node type name: %s'
-                    % safe_repr(argument),
+                    'function "get_nodes_of_type" argument is not a valid node type name: {0}'
+                    .format(safe_repr(argument)),
                     locator=self.locator)
 
     @property
@@ -327,14 +356,15 @@
             node_type_name = as_raw(node_type_name)
         return {'get_nodes_of_type': node_type_name}
 
-    def _evaluate(self, context, container):
+    def __evaluate__(self, container):
         pass
 
+
 #
 # Artifact
 #
 
-@dsl_specification('4.8.1', 'tosca-simple-1.0') # pylint: disable=abstract-method
+@implements_specification('4.8.1', 'tosca-simple-1.0') # pylint: disable=abstract-method
 class GetArtifact(Function):
     """
     The :code:`get_artifact` function is used to retrieve artifact location between modelable
@@ -346,8 +376,8 @@
 
         if (not isinstance(argument, list)) or (len(argument) < 2) or (len(argument) > 4):
             raise InvalidValueError(
-                'function "get_artifact" argument must be a list of 2 to 4 parameters: %s'
-                % safe_repr(argument),
+                'function "get_artifact" argument must be a list of 2 to 4 parameters: {0}'
+                .format(safe_repr(argument)),
                 locator=self.locator)
 
         self.modelable_entity_name = parse_string_expression(context, presentation, 'get_artifact',
@@ -370,6 +400,7 @@
             location = as_raw(location)
         return {'get_artifacts': [self.modelable_entity_name, artifact_name, location, self.remove]}
 
+
 #
 # Utils
 #
@@ -386,6 +417,7 @@
                 return True, None
     return False, None
 
+
 def parse_string_expression(context, presentation, name, index, explanation, value): # pylint: disable=unused-argument
     is_function, func = get_function(context, presentation, value)
     if is_function:
@@ -394,6 +426,7 @@
         value = str(value)
     return value
 
+
 def parse_int(context, presentation, name, index, explanation, value): # pylint: disable=unused-argument
     if not isinstance(value, int):
         try:
@@ -403,11 +436,13 @@
                                 presentation._locator)
     return value
 
+
 def parse_bool(context, presentation, name, index, explanation, value): # pylint: disable=unused-argument
     if not isinstance(value, bool):
         raise invalid_value(name, index, 'a boolean', explanation, value, presentation._locator)
     return value
 
+
 def parse_modelable_entity_name(context, presentation, name, index, value):
     value = parse_string_expression(context, presentation, name, index, 'the modelable entity name',
                                     value)
@@ -436,66 +471,104 @@
             or {}
         if (value not in node_templates) and (value not in relationship_templates):
             raise InvalidValueError(
-                'function "%s" parameter %d is not a valid modelable entity name: %s'
-                % (name, index + 1, safe_repr(value)),
+                'function "{0}" parameter {1:d} is not a valid modelable entity name: {2}'
+                .format(name, index + 1, safe_repr(value)),
                 locator=presentation._locator, level=Issue.BETWEEN_TYPES)
     return value
 
+
 def parse_self(presentation):
-    from .templates import NodeTemplate, RelationshipTemplate
-    from .types import NodeType, RelationshipType
+    from ..types import (NodeType, RelationshipType)
+    from ..templates import (
+        NodeTemplate as NodeTemplatePresentation,
+        RelationshipTemplate as RelationshipTemplatePresentation
+    )
 
     if presentation is None:
         return None, None
-    elif isinstance(presentation, NodeTemplate) or isinstance(presentation, NodeType):
+    elif isinstance(presentation, NodeTemplatePresentation) or isinstance(presentation, NodeType):
         return presentation, 'node_template'
-    elif isinstance(presentation, RelationshipTemplate) \
+    elif isinstance(presentation, RelationshipTemplatePresentation) \
         or isinstance(presentation, RelationshipType):
         return presentation, 'relationship_template'
     else:
         return parse_self(presentation._container)
 
-@dsl_specification('4.1', 'tosca-simple-1.0')
-def get_modelable_entities(context, container, locator, modelable_entity_name):
+
+def evaluate(value, final, container_holder):
+    """
+    Calls ``__evaluate__`` and passes on ``final`` state.
+    """
+
+    if hasattr(value, '__evaluate__'):
+        value = value.__evaluate__(container_holder)
+        if not value.final:
+            final = False
+        return value.value, final
+    else:
+        return value, final
+
+
+@implements_specification('4.1', 'tosca-simple-1.0')
+def get_modelable_entities(container_holder, name, locator, modelable_entity_name):
     """
     The following keywords MAY be used in some TOSCA function in place of a TOSCA Node or
     Relationship Template name.
     """
 
     if modelable_entity_name == 'SELF':
-        return get_self(context, container)
+        return get_self(container_holder, name, locator)
     elif modelable_entity_name == 'HOST':
-        return get_host(context, container)
+        return get_hosts(container_holder, name, locator)
     elif modelable_entity_name == 'SOURCE':
-        return get_source(context, container)
+        return get_source(container_holder, name, locator)
     elif modelable_entity_name == 'TARGET':
-        return get_target(context, container)
+        return get_target(container_holder, name, locator)
     elif isinstance(modelable_entity_name, basestring):
-        node_templates = \
-            context.presentation.get('service_template', 'topology_template', 'node_templates') \
-            or {}
-        if modelable_entity_name in node_templates:
-            return [node_templates[modelable_entity_name]]
-        relationship_templates = \
-            context.presentation.get('service_template', 'topology_template',
-                                     'relationship_templates') \
-            or {}
-        if modelable_entity_name in relationship_templates:
-            return [relationship_templates[modelable_entity_name]]
+        modelable_entities = []
 
-    raise InvalidValueError('function "get_property" could not find modelable entity "%s"'
-                            % modelable_entity_name,
+        service = container_holder.service
+        if service is not None:
+            for node in service.nodes.itervalues():
+                if node.node_template.name == modelable_entity_name:
+                    modelable_entities.append(node)
+        else:
+            service_template = container_holder.service_template
+            if service_template is not None:
+                for node_template in service_template.node_templates.itervalues():
+                    if node_template.name == modelable_entity_name:
+                        modelable_entities.append(node_template)
+
+        if not modelable_entities:
+            raise CannotEvaluateFunctionException()
+
+        return modelable_entities
+
+    raise InvalidValueError('function "{0}" could not find modelable entity "{1}"'
+                            .format(name, modelable_entity_name),
                             locator=locator)
 
-def get_self(context, container): # pylint: disable=unused-argument
+
+def get_self(container_holder, name, locator):
     """
     A TOSCA orchestrator will interpret this keyword as the Node or Relationship Template instance
     that contains the function at the time the function is evaluated.
     """
 
+    container = container_holder.container
+    if (not isinstance(container, Node)) and \
+        (not isinstance(container, NodeTemplate)) and \
+        (not isinstance(container, Relationship)) and \
+        (not isinstance(container, RelationshipTemplate)):
+        raise InvalidValueError('function "{0}" refers to "SELF" but it is not contained in '
+                                'a node or a relationship: {1}'.format(name,
+                                                                       full_type_name(container)),
+                                locator=locator)
+
     return [container]
 
-def get_host(context, container): # pylint: disable=unused-argument
+
+def get_hosts(container_holder, name, locator):
     """
     A TOSCA orchestrator will interpret this keyword to refer to the all nodes that "host" the node
     using this reference (i.e., as identified by its HostedOn relationship).
@@ -507,30 +580,98 @@
     ends.
     """
 
-    return []
+    container = container_holder.container
+    if (not isinstance(container, Node)) and (not isinstance(container, NodeTemplate)):
+        raise InvalidValueError('function "{0}" refers to "HOST" but it is not contained in '
+                                'a node: {1}'.format(name, full_type_name(container)),
+                                locator=locator)
 
-def get_source(context, container): # pylint: disable=unused-argument
+    if not isinstance(container, Node):
+        # NodeTemplate does not have "host"; we'll wait until instantiation
+        raise CannotEvaluateFunctionException()
+
+    host = container.host
+    if host is None:
+        # We might have a host later
+        raise CannotEvaluateFunctionException()
+
+    return [host]
+
+
+def get_source(container_holder, name, locator):
     """
     A TOSCA orchestrator will interpret this keyword as the Node Template instance that is at the
     source end of the relationship that contains the referencing function.
     """
 
-    return []
+    container = container_holder.container
+    if (not isinstance(container, Relationship)) and \
+        (not isinstance(container, RelationshipTemplate)):
+        raise InvalidValueError('function "{0}" refers to "SOURCE" but it is not contained in '
+                                'a relationship: {1}'.format(name, full_type_name(container)),
+                                locator=locator)
 
-def get_target(context, container): # pylint: disable=unused-argument
+    if not isinstance(container, RelationshipTemplate):
+        # RelationshipTemplate does not have "source_node"; we'll wait until instantiation
+        raise CannotEvaluateFunctionException()
+
+    return [container.source_node]
+
+
+def get_target(container_holder, name, locator):
     """
     A TOSCA orchestrator will interpret this keyword as the Node Template instance that is at the
     target end of the relationship that contains the referencing function.
     """
 
+    container = container_holder.container
+    if (not isinstance(container, Relationship)) and \
+        (not isinstance(container, RelationshipTemplate)):
+        raise InvalidValueError('function "{0}" refers to "TARGET" but it is not contained in '
+                                'a relationship: {1}'.format(name, full_type_name(container)),
+                                locator=locator)
+
+    if not isinstance(container, RelationshipTemplate):
+        # RelationshipTemplate does not have "target_node"; we'll wait until instantiation
+        raise CannotEvaluateFunctionException()
+
+    return [container.target_node]
+
+
+def get_modelable_entity_parameter(modelable_entity, parameters, nested_parameter_name_or_index):
+    if not parameters:
+        return False, True, None
+
+    found = True
+    final = True
+    value = parameters
+
+    for name_or_index in nested_parameter_name_or_index:
+        if (isinstance(value, dict) and (name_or_index in value)) \
+            or ((isinstance(value, list) and (name_or_index < len(value)))):
+            value = value[name_or_index] # Parameter
+            # We are not using Parameter.value, but rather Parameter._value, because we want to make
+            # sure to get "final" (it is swallowed by Parameter.value)
+            value, final = evaluate(value._value, final, value)
+        else:
+            found = False
+            break
+
+    return Evaluation(value, final) if found else None
+
+
 def invalid_modelable_entity_name(name, index, value, locator, contexts):
-    return InvalidValueError('function "%s" parameter %d can be "%s" only in %s'
-                             % (name, index + 1, value, contexts),
+    return InvalidValueError('function "{0}" parameter {1:d} can be "{2}" only in {3}'
+                             .format(name, index + 1, value, contexts),
                              locator=locator, level=Issue.FIELD)
 
+
 def invalid_value(name, index, the_type, explanation, value, locator):
     return InvalidValueError(
-        'function "%s" %s is not %s%s: %s'
-        % (name, ('parameter %d' % (index + 1)) if index is not None else 'argument',
-           the_type, (', %s' % explanation) if explanation is not None else '', safe_repr(value)),
+        'function "{0}" {1} is not {2}{3}: {4}'
+        .format(name,
+                'parameter {0:d}'.format(index + 1) if index is not None else 'argument',
+                the_type,
+                ', {0}'.format(explanation) if explanation is not None else '',
+                safe_repr(value)),
         locator=locator, level=Issue.FIELD)
diff --git a/extensions/aria_extension_tosca/simple_v1_0/modeling/properties.py b/extensions/aria_extension_tosca/simple_v1_0/modeling/properties.py
index f61cb99..9c3ea42 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/modeling/properties.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/modeling/properties.py
@@ -58,7 +58,8 @@
 # NodeTemplate, RelationshipTemplate, GroupTemplate, PolicyTemplate
 #
 
-def get_assigned_and_defined_property_values(context, presentation):
+def get_assigned_and_defined_property_values(context, presentation, field_name='property',
+                                             field_name_plural='properties'):
     """
     Returns the assigned property values while making sure they are defined in our type.
 
@@ -70,8 +71,9 @@
     values = OrderedDict()
 
     the_type = presentation._get_type(context)
-    assignments = presentation.properties
-    definitions = the_type._get_properties(context) if the_type is not None else None
+    assignments = getattr(presentation, field_name_plural)
+    get_fn_name = '_get_{0}'.format(field_name_plural)
+    definitions = getattr(the_type, get_fn_name)(context) if the_type is not None else None
 
     # Fill in our assignments, but make sure they are defined
     if assignments:
@@ -80,14 +82,14 @@
                 definition = definitions[name]
                 values[name] = coerce_property_value(context, value, definition, value.value)
             else:
-                context.validation.report('assignment to undefined property "%s" in "%s"'
-                                          % (name, presentation._fullname),
+                context.validation.report('assignment to undefined {0} "{1}" in "{2}"'
+                                          .format(field_name, name, presentation._fullname),
                                           locator=value._locator, level=Issue.BETWEEN_TYPES)
 
     # Fill in defaults from the definitions
     if definitions:
         for name, definition in definitions.iteritems():
-            if (values.get(name) is None) and (definition.default is not None):
+            if values.get(name) is None:
                 values[name] = coerce_property_value(context, presentation, definition,
                                                      definition.default)
 
@@ -181,7 +183,8 @@
 def coerce_property_value(context, presentation, definition, value, aspect=None):
     the_type = definition._get_type(context) if definition is not None else None
     entry_schema = definition.entry_schema if definition is not None else None
-    constraints = definition._get_constraints(context) if definition is not None else None
+    constraints = definition._get_constraints(context) \
+        if ((definition is not None) and hasattr(definition, '_get_constraints')) else None
     value = coerce_value(context, presentation, the_type, entry_schema, constraints, value, aspect)
     if (the_type is not None) and hasattr(the_type, '_name'):
         type_name = the_type._name
diff --git a/extensions/aria_extension_tosca/simple_v1_0/presentation/field_validators.py b/extensions/aria_extension_tosca/simple_v1_0/presentation/field_validators.py
index 6ff4384..d7b03ae 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/presentation/field_validators.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/presentation/field_validators.py
@@ -16,7 +16,7 @@
 import re
 
 from aria.utils.formatting import safe_repr
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (report_issue_for_unknown_type, derived_from_validator)
 from aria.parser.validation import Issue
 
@@ -28,8 +28,7 @@
 # NodeTemplate, RelationshipTemplate
 #
 
-@dsl_specification('3.7.3.3', 'tosca-simple-1.0')
-@dsl_specification('3.7.4.3', 'tosca-simple-1.0')
+@implements_specification('3.7.3.3', 'tosca-simple-1.0')
 def copy_validator(template_type_name, templates_dict_name):
     """
     Makes sure that the field refers to an existing template defined in the root presenter.
@@ -304,8 +303,12 @@
     value = getattr(presentation, field.name)
     if value is not None:
         try:
-            # Note: the TOSCA 1.0 spec does not specify the regular expression grammar, so we will
-            # just use Python's
+            # From TOSCA 1.0 3.5.2.1:
+            #
+            # "Note: Future drafts of this specification will detail the use of regular expressions
+            # and reference an appropriate standardized grammar."
+            #
+            # So we will just use Python's.
             re.compile(value)
         except re.error as e:
             context.validation.report(
diff --git a/extensions/aria_extension_tosca/simple_v1_0/presenter.py b/extensions/aria_extension_tosca/simple_v1_0/presenter.py
index c88decd..f64078f 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/presenter.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/presenter.py
@@ -17,9 +17,9 @@
 from aria.utils.caching import cachedmethod
 from aria.parser.presentation import Presenter
 
-from .functions import (Concat, Token, GetInput, GetProperty, GetAttribute, GetOperationOutput,
-                        GetNodesOfType, GetArtifact)
 from .modeling import create_service_template_model
+from .modeling.functions import (Concat, Token, GetInput, GetProperty, GetAttribute,
+                                 GetOperationOutput, GetNodesOfType, GetArtifact)
 from .templates import ServiceTemplate
 
 class ToscaSimplePresenter1_0(Presenter): # pylint: disable=invalid-name,abstract-method
diff --git a/extensions/aria_extension_tosca/simple_v1_0/templates.py b/extensions/aria_extension_tosca/simple_v1_0/templates.py
index 6860b72..ce6b5d9 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/templates.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/templates.py
@@ -15,7 +15,7 @@
 
 from aria.utils.collections import FrozenDict, FrozenList
 from aria.utils.caching import cachedmethod
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (has_fields, primitive_field, primitive_list_field,
                                       object_field, object_list_field, object_dict_field,
                                       object_sequenced_list_field, field_validator,
@@ -26,7 +26,7 @@
 from .definitions import ParameterDefinition
 from .filters import NodeFilter
 from .misc import (Description, MetaData, Repository, Import, SubstitutionMappings)
-from .modeling.properties import get_assigned_and_defined_property_values, get_parameter_values
+from .modeling.properties import (get_assigned_and_defined_property_values, get_parameter_values)
 from .modeling.interfaces import get_template_interfaces
 from .modeling.requirements import get_template_requirements
 from .modeling.capabilities import get_template_capabilities
@@ -41,7 +41,7 @@
                     NodeType, GroupType, PolicyType)
 
 @has_fields
-@dsl_specification('3.7.3', 'tosca-simple-1.0')
+@implements_specification('3.7.3', 'tosca-simple-1.0')
 class NodeTemplate(ExtensiblePresentation):
     """
     A Node Template specifies the occurrence of a manageable software component as part of an
@@ -160,6 +160,11 @@
         return FrozenDict(get_assigned_and_defined_property_values(context, self))
 
     @cachedmethod
+    def _get_attribute_default_values(self, context):
+        return FrozenDict(get_assigned_and_defined_property_values(context, self,
+                                                                   'attribute', 'attributes'))
+
+    @cachedmethod
     def _get_requirements(self, context):
         return FrozenList(get_template_requirements(context, self))
 
@@ -198,7 +203,7 @@
             'copy'))
 
 @has_fields
-@dsl_specification('3.7.4', 'tosca-simple-1.0')
+@implements_specification('3.7.4', 'tosca-simple-1.0')
 class RelationshipTemplate(ExtensiblePresentation):
     """
     A Relationship Template specifies the occurrence of a manageable relationship between node
@@ -297,7 +302,7 @@
             'copy'))
 
 @has_fields
-@dsl_specification('3.7.5', 'tosca-simple-1.0')
+@implements_specification('3.7.5', 'tosca-simple-1.0')
 class GroupTemplate(ExtensiblePresentation):
     """
     A group definition defines a logical grouping of node templates, typically for management
@@ -370,7 +375,7 @@
         self._get_interfaces(context)
 
 @has_fields
-@dsl_specification('3.7.6', 'tosca-simple-1.0')
+@implements_specification('3.7.6', 'tosca-simple-1.0')
 class PolicyTemplate(ExtensiblePresentation):
     """
     A policy definition defines a policy that can be associated with a TOSCA topology or top-level
@@ -434,7 +439,7 @@
         self._get_property_values(context)
 
 @has_fields
-@dsl_specification('3.8', 'tosca-simple-1.0')
+@implements_specification('3.8', 'tosca-simple-1.0')
 class TopologyTemplate(ExtensiblePresentation):
     """
     This section defines the topology template of a cloud application. The main ingredients of the
@@ -544,7 +549,7 @@
             'substitution_mappings'))
 
 @has_fields
-@dsl_specification('3.9', 'tosca-simple-1.0')
+@implements_specification('3.9', 'tosca-simple-1.0')
 class ServiceTemplate(ExtensiblePresentation):
     """
     See the `TOSCA Simple Profile v1.0 cos01 specification <http://docs.oasis-open.org/tosca
@@ -553,7 +558,7 @@
     """
 
     @primitive_field(str)
-    @dsl_specification('3.9.3.1', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.1', 'tosca-simple-1.0')
     def tosca_definitions_version(self):
         """
         Defines the version of the TOSCA Simple Profile specification the template (grammar)
@@ -580,7 +585,7 @@
         """
 
     @object_field(Description)
-    @dsl_specification('3.9.3.6', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.6', 'tosca-simple-1.0')
     def description(self):
         """
         Declares a description for this Service Template and its contents.
@@ -589,7 +594,7 @@
         """
 
     @primitive_field()
-    @dsl_specification('3.9.3.7', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.7', 'tosca-simple-1.0')
     def dsl_definitions(self):
         """
         Declares optional DSL-specific definitions and conventions. For example, in YAML, this
@@ -602,7 +607,7 @@
         """
 
     @object_dict_field(Repository)
-    @dsl_specification('3.9.3.8', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.8', 'tosca-simple-1.0')
     def repositories(self):
         """
         Declares the list of external repositories which contain artifacts that are referenced in
@@ -613,7 +618,7 @@
         """
 
     @object_list_field(Import)
-    @dsl_specification('3.9.3.9', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.9', 'tosca-simple-1.0')
     def imports(self):
         """
         Declares import statements external TOSCA Definitions documents. For example, these may be
@@ -623,7 +628,7 @@
         """
 
     @object_dict_field(ArtifactType)
-    @dsl_specification('3.9.3.10', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.10', 'tosca-simple-1.0')
     def artifact_types(self):
         """
         This section contains an optional list of artifact type definitions for use in the service
@@ -633,7 +638,7 @@
         """
 
     @object_dict_field(DataType)
-    @dsl_specification('3.9.3.11', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.11', 'tosca-simple-1.0')
     def data_types(self):
         """
         Declares a list of optional TOSCA Data Type definitions.
@@ -642,7 +647,7 @@
         """
 
     @object_dict_field(CapabilityType)
-    @dsl_specification('3.9.3.12', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.12', 'tosca-simple-1.0')
     def capability_types(self):
         """
         This section contains an optional list of capability type definitions for use in the service
@@ -652,7 +657,7 @@
         """
 
     @object_dict_field(InterfaceType)
-    @dsl_specification('3.9.3.13', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.13', 'tosca-simple-1.0')
     def interface_types(self):
         """
         This section contains an optional list of interface type definitions for use in the service
@@ -662,7 +667,7 @@
         """
 
     @object_dict_field(RelationshipType)
-    @dsl_specification('3.9.3.14', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.14', 'tosca-simple-1.0')
     def relationship_types(self):
         """
         This section contains a set of relationship type definitions for use in the service
@@ -672,7 +677,7 @@
         """
 
     @object_dict_field(NodeType)
-    @dsl_specification('3.9.3.15', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.15', 'tosca-simple-1.0')
     def node_types(self):
         """
         This section contains a set of node type definitions for use in the service template.
@@ -681,7 +686,7 @@
         """
 
     @object_dict_field(GroupType)
-    @dsl_specification('3.9.3.16', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.16', 'tosca-simple-1.0')
     def group_types(self):
         """
         This section contains a list of group type definitions for use in the service template.
@@ -690,7 +695,7 @@
         """
 
     @object_dict_field(PolicyType)
-    @dsl_specification('3.9.3.17', 'tosca-simple-1.0')
+    @implements_specification('3.9.3.17', 'tosca-simple-1.0')
     def policy_types(self):
         """
         This section contains a list of policy type definitions for use in the service template.
diff --git a/extensions/aria_extension_tosca/simple_v1_0/types.py b/extensions/aria_extension_tosca/simple_v1_0/types.py
index 2112f7f..bc80eb9 100644
--- a/extensions/aria_extension_tosca/simple_v1_0/types.py
+++ b/extensions/aria_extension_tosca/simple_v1_0/types.py
@@ -15,7 +15,7 @@
 
 from aria.utils.collections import FrozenDict, FrozenList
 from aria.utils.caching import cachedmethod
-from aria.parser import dsl_specification
+from aria.parser import implements_specification
 from aria.parser.presentation import (has_fields, allow_unknown_fields, primitive_field,
                                       primitive_list_field, object_field, object_dict_field,
                                       object_list_field, object_sequenced_list_field,
@@ -46,7 +46,7 @@
 from .presentation.types import convert_shorthand_to_full_type_name
 
 @has_fields
-@dsl_specification('3.6.3', 'tosca-simple-1.0')
+@implements_specification('3.6.3', 'tosca-simple-1.0')
 class ArtifactType(ExtensiblePresentation):
     """
     An Artifact Type is a reusable entity that defines the type of one or more files that are used
@@ -131,7 +131,7 @@
             'properties'))
 
 @has_fields
-@dsl_specification('3.6.5', 'tosca-simple-1.0')
+@implements_specification('3.6.5', 'tosca-simple-1.0')
 class DataType(ExtensiblePresentation):
     """
     A Data Type definition defines the schema for new named datatypes in TOSCA.
@@ -225,7 +225,7 @@
             'properties'))
 
 @has_fields
-@dsl_specification('3.6.6', 'tosca-simple-1.0')
+@implements_specification('3.6.6', 'tosca-simple-1.0')
 class CapabilityType(ExtensiblePresentation):
     """
     A Capability Type is a reusable entity that describes a kind of capability that a Node Type can
@@ -328,7 +328,7 @@
 
 @allow_unknown_fields
 @has_fields
-@dsl_specification('3.6.4', 'tosca-simple-1.0')
+@implements_specification('3.6.4', 'tosca-simple-1.0')
 class InterfaceType(ExtensiblePresentation):
     """
     An Interface Type is a reusable entity that describes a set of operations that can be used to
@@ -406,7 +406,7 @@
             'operations'))
 
 @has_fields
-@dsl_specification('3.6.9', 'tosca-simple-1.0')
+@implements_specification('3.6.9', 'tosca-simple-1.0')
 class RelationshipType(ExtensiblePresentation):
     """
     A Relationship Type is a reusable entity that defines the type of one or more relationships
@@ -520,7 +520,7 @@
             'interfaces'))
 
 @has_fields
-@dsl_specification('3.6.8', 'tosca-simple-1.0')
+@implements_specification('3.6.8', 'tosca-simple-1.0')
 class NodeType(ExtensiblePresentation):
     """
     A Node Type is a reusable entity that defines the type of one or more Node Templates. As such, a
@@ -668,7 +668,7 @@
             'capabilities'))
 
 @has_fields
-@dsl_specification('3.6.10', 'tosca-simple-1.0')
+@implements_specification('3.6.10', 'tosca-simple-1.0')
 class GroupType(ExtensiblePresentation):
     """
     A Group Type defines logical grouping types for nodes, typically for different management
@@ -781,7 +781,7 @@
             'interfaces'))
 
 @has_fields
-@dsl_specification('3.6.11', 'tosca-simple-1.0')
+@implements_specification('3.6.11', 'tosca-simple-1.0')
 class PolicyType(ExtensiblePresentation):
     """
     A Policy Type defines a type of requirement that affects or governs an application or service's
diff --git a/tests/resources/service-templates/tosca-simple-1.0/node-cellar/node-cellar.yaml b/tests/resources/service-templates/tosca-simple-1.0/node-cellar/node-cellar.yaml
index 349a166..8e80640 100644
--- a/tests/resources/service-templates/tosca-simple-1.0/node-cellar/node-cellar.yaml
+++ b/tests/resources/service-templates/tosca-simple-1.0/node-cellar/node-cellar.yaml
@@ -33,6 +33,7 @@
   - types/mongodb.yaml
   - types/nginx.yaml
   - aria-1.0
+
 dsl_definitions:
 
   default_openstack_credential: &DEFAULT_OPENSTACK_CREDENTIAL
@@ -94,8 +95,11 @@
           properties:
             unpack_credential:
               user: gigaspaces
-              token: { get_property: [ SELF, app_endpoint, protocol ] }
+              token: { get_attribute: [ SELF, tosca_id ] }
+              #token: { get_property: [ SELF, app_endpoint, protocol ] }
               #token: { get_property: [ HOST, flavor_name ] }
+              #token: { token: [ { get_property: [ HOST, flavor_name ] }, '.', 1 ] }
+              #token: { token: [ 'zero.one|two-three', '.|-', 3 ] }
       interfaces:
         Maintenance:
           enable: juju > charm.maintenance_on