8 files changed, 47 insertions, 70 deletions
diff --git a/grc/core/Block.py b/grc/core/Block.py
index 7042ba7702..9572982bf7 100644
--- a/grc/core/Block.py
+++ b/grc/core/Block.py
@@ -332,30 +332,11 @@ class Block(Element):
         self.states['_enabled'] = encoded
 
     # Enable/Disable Aliases
-    def get_enabled(self):
-        """
-        Get the enabled state of the block.
-
-        Returns:
-            true for enabled
-        """
+    @property
+    def enabled(self):
+        """Get the enabled state of the block"""
         return self.state != 'disabled'
 
-    def set_enabled(self, enabled):
-        """
-        Set the enabled state of the block.
-
-        Args:
-            enabled: true for enabled
-
-        Returns:
-            True if block changed state
-        """
-        old_state = self.state
-        new_state = 'enabled' if enabled else 'disabled'
-        self.state = new_state
-        return old_state != new_state
-
     # Block bypassing
     def get_bypassed(self):
         """
@@ -739,7 +720,8 @@ class DummyBlock(Block):
     def is_valid(self):
         return False
 
-    def get_enabled(self):
+    @property
+    def enabled(self):
         return False
 
     def add_missing_port(self, key, dir):
diff --git a/grc/core/Connection.py b/grc/core/Connection.py
index aec7a217b3..6be1ccb2aa 100644
--- a/grc/core/Connection.py
+++ b/grc/core/Connection.py
@@ -76,6 +76,24 @@ class Connection(Element):
             raise ValueError('Connection could not isolate sink')
         return source, sink
 
+    @lazy_property
+    def source_block(self):
+        return self.source_port.parent_block
+
+    @lazy_property
+    def sink_block(self):
+        return self.sink_port.parent_block
+
+    @property
+    def enabled(self):
+        """
+        Get the enabled state of this connection.
+
+        Returns:
+            true if source and sink blocks are enabled
+        """
+        return self.source_block.enabled and self.sink_block.enabled
+
     def __str__(self):
         return 'Connection (\n\t{}\n\t\t{}\n\t{}\n\t\t{}\n)'.format(
             self.source_block, self.source_port, self.sink_block, self.sink_port,
@@ -125,23 +143,6 @@ class Connection(Element):
         if source_size != sink_size:
             self.add_error_message('Source IO size "{}" does not match sink IO size "{}".'.format(source_size, sink_size))
 
-    def get_enabled(self):
-        """
-        Get the enabled state of this connection.
-
-        Returns:
-            true if source and sink blocks are enabled
-        """
-        return self.source_block.get_enabled() and self.sink_block.get_enabled()
-
-    @lazy_property
-    def source_block(self):
-        return self.source_port.parent_block
-
-    @lazy_property
-    def sink_block(self):
-        return self.sink_port.parent_block
-
     ##############################################
     # Import/Export Methods
     ##############################################
diff --git a/grc/core/Element.py b/grc/core/Element.py
index 415b086402..32afabbed7 100644
--- a/grc/core/Element.py
+++ b/grc/core/Element.py
@@ -66,7 +66,7 @@ class Element(object):
         Returns:
             true when the element is enabled and has no error messages or is bypassed
         """
-        return (not self.get_error_messages() or not self.get_enabled()) or self.get_bypassed()
+        return (not self.get_error_messages() or not self.enabled) or self.get_bypassed()
 
     def add_error_message(self, msg):
         """
@@ -88,7 +88,7 @@ class Element(object):
         """
         error_messages = list(self._error_messages)  # Make a copy
         for child in self.get_children():
-            if not child.get_enabled() or child.get_bypassed():
+            if not child.enabled or child.get_bypassed():
                 continue
             for msg in child.get_error_messages():
                 error_messages.append("{}:\n\t{}".format(child, msg.replace("\n", "\n\t")))
@@ -102,7 +102,8 @@ class Element(object):
         for child in self.get_children():
             child.rewrite()
 
-    def get_enabled(self):
+    @property
+    def enabled(self):
         return True
 
     def get_bypassed(self):
@@ -141,7 +142,7 @@ class Element(object):
 
     def reset_parents_by_type(self):
         """Reset all lazy properties"""
-        for name, obj in vars(Element):
+        for name, obj in vars(Element):  # explicitly only in Element, not subclasses
             if isinstance(obj, lazy_property):
                 delattr(self, name)
 
diff --git a/grc/core/Element.pyi b/grc/core/Element.pyi
index 46c6d3480d..2a2aed401c 100644
--- a/grc/core/Element.pyi
+++ b/grc/core/Element.pyi
@@ -15,32 +15,27 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 
+from typing import Union
+
 from . import Platform, FlowGraph, Block
 
-def lazy_property(func):
-    return func
+lazy_property = property  # fixme: descriptors don't seems to be supported
 
 
 class Element(object):
 
-    def __init__(self, parent=None):
-        ...
+    def __init__(self, parent: Union[None, 'Element'] = None): ...
 
-    @property
-    def parent(self): -> 'Element'
-        ...
+    @lazy_property
+    def parent(self) -> 'Element': ...
 
-    def get_parent_by_type(self, cls): -> 'Element'
-        ...
+    def get_parent_by_type(self, cls) -> Union[None, 'Element']: ...
 
     @lazy_property
-    def parent_platform(self): -> Platform.Platform
-        ...
+    def parent_platform(self) -> Platform.Platform: ...
 
     @lazy_property
-    def parent_flowgraph(self): -> FlowGraph.FlowGraph
-        ...
+    def parent_flowgraph(self) -> FlowGraph.FlowGraph: ...
 
     @lazy_property
-    def parent_block(self): -> Block.Block
-        ...
+    def parent_block(self) -> Block.Block: ...
diff --git a/grc/core/FlowGraph.py b/grc/core/FlowGraph.py
index cb2a56ce7d..97a4c37353 100644
--- a/grc/core/FlowGraph.py
+++ b/grc/core/FlowGraph.py
@@ -21,11 +21,9 @@ import imp
 import time
 import re
 from itertools import chain
-from operator import methodcaller, attrgetter
+from operator import methodcaller
 import collections
 
-from six.moves import filter
-
 from . import Messages
 from .Constants import FLOW_GRAPH_FILE_FORMAT_VERSION
 from .Element import Element
@@ -86,7 +84,7 @@ class FlowGraph(Element):
         Returns:
             a sorted list of variable blocks in order of dependency (indep -> dep)
         """
-        variables = list(filter(attrgetter('is_variable'), self.iter_enabled_blocks()))
+        variables = [block for block in self.iter_enabled_blocks() if block.is_variable]
         return expr_utils.sort_objects(variables, methodcaller('get_id'), methodcaller('get_var_make'))
 
     def get_parameters(self):
@@ -142,7 +140,7 @@ class FlowGraph(Element):
         """
         Get an iterator of all blocks that are enabled and not bypassed.
         """
-        return filter(methodcaller('get_enabled'), self.blocks)
+        return (block for block in self.blocks if block.enabled)
 
     def get_enabled_blocks(self):
         """
@@ -160,7 +158,7 @@ class FlowGraph(Element):
         Returns:
             a list of blocks
         """
-        return list(filter(methodcaller('get_bypassed'), self.blocks))
+        return [block for block in self.blocks if block.get_bypassed()]
 
     def get_enabled_connections(self):
         """
@@ -169,7 +167,7 @@ class FlowGraph(Element):
         Returns:
             a list of connections
         """
-        return list(filter(methodcaller('get_enabled'), self.connections))
+        return [connection for connection in self.connections if connection.enabled]
 
     def get_option(self, key):
         """
diff --git a/grc/core/Port.py b/grc/core/Port.py
index f7046ad8c8..0d9298fb05 100644
--- a/grc/core/Port.py
+++ b/grc/core/Port.py
@@ -332,7 +332,7 @@ class Port(Element):
         Returns:
             a list of connection objects
         """
-        return [c for c in self.get_connections() if c.get_enabled()]
+        return [c for c in self.get_connections() if c.enabled]
 
     def get_associated_ports(self):
         if not self.get_type() == 'bus':
diff --git a/grc/core/generator/Generator.py b/grc/core/generator/Generator.py
index dcbf767835..7c9a1eca73 100644
--- a/grc/core/generator/Generator.py
+++ b/grc/core/generator/Generator.py
@@ -145,7 +145,7 @@ class TopBlockGenerator(object):
             return code
 
         blocks_all = expr_utils.sort_objects(
-            [b for b in fg.blocks if b.get_enabled() and not b.get_bypassed()],
+            [b for b in fg.blocks if b.enabled and not b.get_bypassed()],
             operator.methodcaller('get_id'), _get_block_sort_text
         )
         deprecated_block_keys = set(b.name for b in blocks_all if b.is_deprecated)
@@ -198,7 +198,7 @@ class TopBlockGenerator(object):
 
             # Loop through all the downstream connections
             for sink in (c for c in connections if c.source_port == block.sources[0]):
-                if not sink.get_enabled():
+                if not sink.enabled:
                     # Ignore disabled connections
                     continue
                 sink_port = sink.sink_port
diff --git a/grc/core/utils/_complexity.py b/grc/core/utils/_complexity.py
index 6da16eb28d..c0f3ae9de4 100644
--- a/grc/core/utils/_complexity.py
+++ b/grc/core/utils/_complexity.py
@@ -29,7 +29,7 @@ def calculate_flowgraph_complexity(flowgraph):
     blocks = float(len(flowgraph.blocks))
     connections = float(len(flowgraph.connections))
     elements = blocks + connections
-    disabled_connections = sum(not c.get_enabled() for c in flowgraph.connections)
+    disabled_connections = sum(not c.enabled for c in flowgraph.connections)
 
     variables = elements - blocks - connections
     enabled = float(len(flowgraph.get_enabled_blocks()))