Replace IECore.Enum with standard types from enum module

Now we're Python 3 only we can use the standard `enum` module, which provides a more comprehensive framework than `IECore.Enum`. For the most part its a drop-in replacement, but there are a few gotchas to be aware of, which I have hopefully dealt with everywhere necessary :

- `str( e )` returns only `<name>` for `IECore.Enum` but returns `<className>.<name>` for `enum.Enum`.
- `int( e )` is provided by default for `IECore.Enum`, but not by `enum.Enum`, so we must use `enum.IntEnum` when that is needed.
- `IECore.Enum` values start at 0, but `enum.Enum` values start at 1 by default. Where this is important (see Wedge), we must specify `start = 0`.

Changes.md

@@ -18,6 +18,7 @@ Breaking Changes
 - StringPlug : Removed deprecated `precomputedHash` argument from `getValue()` method.
 - OpenColorIOContext : Removed `configEnabledPlug()`, `configValuePlug()`, `workingSpaceEnabledPlug()` and `workingSpaceValuePlug()` methods. Use the OptionalValuePlug child accessors instead.
 - Windows launch script : Removed the hardcoded `/debugexe` switch used when `GAFFER_DEBUG` is enabled, making it possible to use debuggers other than Visual Studio. Debug switches can be added to the `GAFFER_DEBUGGER` environment variable instead.
+- Enums : Replaced `IECore.Enum` types with standard Python types from the `enum` module.
 
 1.3.x.x (relative to 1.3.7.0)
 =======

python/GafferCortexUI/OpDialogue.py

@@ -35,6 +35,7 @@
 #
 ##########################################################################
 
+import enum
 import sys
 import threading
 import traceback
@@ -66,7 +67,7 @@ class OpDialogue( GafferUI.Dialogue ) :
 	#
 	# NoneByDefault : deprecated - the same as DisplayResult
 	# CloseByDefault : deprecated - the same as DisplayResult
-	PostExecuteBehaviour = IECore.Enum.create( "FromUserData", "None_", "Close", "DisplayResult", "DisplayResultAndClose", "NoneByDefault", "CloseByDefault" )
+	PostExecuteBehaviour = enum.Enum( "PostExecuteBehaviour", [ "FromUserData", "None_", "Close", "DisplayResult", "DisplayResultAndClose", "NoneByDefault", "CloseByDefault" ] )
 
 	## Defines which button has the focus when the op is displayed for editing.
 	#
@@ -79,7 +80,7 @@ class OpDialogue( GafferUI.Dialogue ) :
 	# OK : The OK button has the focus.
 	#
 	# Cancel : The cancel button has the focus.
-	DefaultButton = IECore.Enum.create( "FromUserData", "None_", "OK", "Cancel" )
+	DefaultButton = enum.Enum( "DefaultButton", [ "FromUserData", "None_", "OK", "Cancel" ] )
 
 	# If executeInBackground is True, then the Op will be executed on another
 	# thread, allowing the UI to remain responsive during execution. This is
@@ -254,7 +255,7 @@ def _acceptsClose( self ) :
 		# the op is running in the background.
 		return self.__state != self.__State.Execution
 
-	__State = IECore.Enum.create( "ParameterEditing", "Execution", "ErrorDisplay", "ResultDisplay" )
+	__State = enum.Enum( "__State", [ "ParameterEditing", "Execution", "ErrorDisplay", "ResultDisplay" ] )
 
 	def __initiateParameterEditing( self, *unused ) :
 

python/GafferDispatch/LocalDispatcher.py

@@ -34,6 +34,7 @@
 #
 ##########################################################################
 
+import enum
 import os
 import errno
 import signal
@@ -62,7 +63,7 @@ def __init__( self, name = "LocalDispatcher", jobPool = None ) :
 
 	class Job( object ) :
 
-		Status = IECore.Enum.create( "Waiting", "Running", "Complete", "Failed", "Killed" )
+		Status = enum.IntEnum( "Status", [ "Waiting", "Running", "Complete", "Failed", "Killed" ] )
 
 		def __init__( self, batch, dispatcher ) :
 

python/GafferDispatch/Wedge.py

@@ -34,7 +34,7 @@
 #
 ##########################################################################
 
-import math
+import enum
 import imath
 
 import IECore
@@ -44,7 +44,7 @@
 
 class Wedge( GafferDispatch.TaskContextProcessor ) :
 
-	Mode = IECore.Enum.create( "FloatRange", "IntRange", "ColorRange", "FloatList", "IntList", "StringList" )
+	Mode = enum.IntEnum( "Mode", [ "FloatRange", "IntRange", "ColorRange", "FloatList", "IntList", "StringList" ], start = 0 )
 
 	def __init__( self, name = "Wedge" ) :
 

python/GafferDispatchUI/DispatchDialogue.py

@@ -34,6 +34,7 @@
 #
 ##########################################################################
 
+import enum
 import functools
 import sys
 import threading
@@ -54,7 +55,7 @@ class DispatchDialogue( GafferUI.Dialogue ) :
 	# Close : The dialogue is closed immediately.
 	#
 	# Confirm : The dialogue remains open confirming success, with a button for returning to the editing state.
-	PostDispatchBehaviour = IECore.Enum.create( "Close", "Confirm" )
+	PostDispatchBehaviour = enum.Enum( "PostDispatchBehaviour", [ "Close", "Confirm" ] )
 
 	__dispatchDialogueMenuDefinition = None
 

python/GafferSceneTest/SceneNodeTest.py

@@ -35,6 +35,7 @@
 #
 ##########################################################################
 
+import enum
 import inspect
 import unittest
 import time
@@ -218,7 +219,7 @@ def testDerivingInPython( self ) :
 
 		class SphereOrCube( GafferScene.SceneNode ) :
 
-			Type = IECore.Enum.create( "Sphere", "Cube" )
+			Type = enum.IntEnum( "Type", [ "Sphere", "Cube" ], start = 0 )
 
 			def __init__( self, name = "SphereOrCube" ) :
 

python/GafferSceneUI/CryptomatteUI.py

@@ -34,6 +34,7 @@
 #
 ##########################################################################
 
+import enum
 import functools
 import imath
 import re
@@ -293,7 +294,7 @@ def __layerPresetValues( plug ) :
 GafferUI.Pointer.registerPointer( "removeNames", GafferUI.Pointer( "removeObjects.png", imath.V2i( 36, 18 ) ) )
 GafferUI.Pointer.registerPointer( "replaceNames", GafferUI.Pointer( "replaceObjects.png", imath.V2i( 36, 18 ) ) )
 
-__DropMode = IECore.Enum.create( "None_", "Add", "Remove", "Replace" )
+__DropMode = enum.Enum( "__DropMode", [ "None_", "Add", "Remove", "Replace" ] )
 
 __originalDragPointer = None
 

python/GafferSceneUI/PathFilterUI.py

@@ -34,7 +34,7 @@
 #
 ##########################################################################
 
-import types
+import enum
 import imath
 import functools
 from collections import deque
@@ -236,7 +236,7 @@ def __popupMenu( menuDefinition, plugValueWidget ) :
 GafferUI.Pointer.registerPointer( "removeObjects", GafferUI.Pointer( "removeObjects.png", imath.V2i( 53, 14 ) ) )
 GafferUI.Pointer.registerPointer( "replaceObjects", GafferUI.Pointer( "replaceObjects.png", imath.V2i( 53, 14 ) ) )
 
-__DropMode = IECore.Enum.create( "None_", "Add", "Remove", "Replace" )
+__DropMode = enum.Enum( "__DropMode", [ "None_", "Add", "Remove", "Replace" ] )
 
 __originalDragPointer = None
 

python/GafferSceneUI/SceneInspector.py

@@ -35,6 +35,7 @@
 #
 ##########################################################################
 
+import enum
 import math
 import difflib
 import html
@@ -332,7 +333,7 @@ def update( self, values ) :
 # with background colours appropriate to the relationship between the two.
 class SideBySideDiff( Diff ) :
 
-	Background = IECore.Enum.create( "A", "B", "AB", "Other" )
+	Background = enum.Enum( "Background", [ "A", "B", "AB", "Other" ] )
 
 	def __init__( self, **kw ) :
 
@@ -412,8 +413,8 @@ def update( self, values, visibilities = None, backgrounds = None ) :
 				continue
 
 			repolish = False
-			if str(backgrounds[i]) != frame._qtWidget().property( "gafferDiff" ) :
-				frame._qtWidget().setProperty( "gafferDiff", str(backgrounds[i]) )
+			if backgrounds[i].name != frame._qtWidget().property( "gafferDiff" ) :
+				frame._qtWidget().setProperty( "gafferDiff", backgrounds[i].name )
 				repolish = True
 
 			if i == 0 :
@@ -1238,7 +1239,7 @@ def __nodeSetMemberRemoved( self, set, node ) :
 
 class _Rail( GafferUI.ListContainer ) :
 
-	Type = IECore.Enum.create( "Top", "Middle", "Gap", "Bottom", "Single" )
+	Type = enum.Enum( "Type", [ "Top", "Middle", "Gap", "Bottom", "Single" ] )
 
 	def __init__( self, type, **kw ) :
 

python/GafferUI/BoolWidget.py

@@ -34,9 +34,7 @@
 #
 ##########################################################################
 
-import types
-
-import IECore
+import enum
 
 import Gaffer
 import GafferUI
@@ -47,10 +45,10 @@
 
 class BoolWidget( GafferUI.Widget ) :
 
-	DisplayMode = IECore.Enum.create( "CheckBox", "Switch", "Tool" )
+	DisplayMode = enum.Enum( "DisplayMode", [ "CheckBox", "Switch", "Tool" ] )
 	# True/False states are deliberately omitted from this enum;
 	# For backwards compatibility we use `bool` values instead.
-	State = IECore.Enum.create( "Indeterminate" )
+	State = enum.Enum( "State", [ "Indeterminate" ] )
 
 	def __init__( self, text="", checked=False, displayMode=DisplayMode.CheckBox, image = None, **kw ) :
 
@@ -118,7 +116,7 @@ def getState( self ) :
 
 	def setDisplayMode( self, displayMode ) :
 
-		self._qtWidget().setProperty( "gafferDisplayMode", str( displayMode ) )
+		self._qtWidget().setProperty( "gafferDisplayMode", displayMode.name )
 		self._qtWidget().setHitMode(
 			_CheckBox.HitMode.Button if displayMode == self.DisplayMode.Tool else _CheckBox.HitMode.CheckBox
 		)
@@ -159,7 +157,7 @@ def __stateChanged( self, state ) :
 
 class _CheckBox( QtWidgets.QCheckBox ) :
 
-	HitMode = IECore.Enum.create( "Button", "CheckBox" )
+	HitMode = enum.Enum( "HitMode", [ "Button", "CheckBox" ] )
 
 	def __init__( self, text, parent = None ) :
 

python/GafferUI/CodeWidget.py

@@ -36,6 +36,7 @@
 
 import os
 import re
+import enum
 import functools
 import token
 import keyword
@@ -284,10 +285,13 @@ def __textChanged( self, widget ) :
 
 class Highlighter( object ) :
 
-	Type = IECore.Enum.create(
-		"SingleQuotedString", "DoubleQuotedString", "Number",
-		"Keyword", "ControlFlow", "Braces", "Operator", "Call",
-		"Comment", "ReservedWord", "Preprocessor"
+	Type = enum.Enum(
+		"Type",
+		[
+			"SingleQuotedString", "DoubleQuotedString", "Number",
+			"Keyword", "ControlFlow", "Braces", "Operator", "Call",
+			"Comment", "ReservedWord", "Preprocessor"
+		]
 	)
 
 	# Specifies a highlight type to be used for the characters

python/GafferUI/ColorChooser.py

@@ -35,11 +35,10 @@
 #
 ##########################################################################
 
+import enum
 import sys
 import imath
 
-import IECore
-
 import Gaffer
 import GafferUI
 
@@ -110,7 +109,7 @@ def _displayTransformChanged( self ) :
 
 class ColorChooser( GafferUI.Widget ) :
 
-	ColorChangedReason = IECore.Enum.create( "Invalid", "SetColor", "Reset" )
+	ColorChangedReason = enum.Enum( "ColorChangedReason", [ "Invalid", "SetColor", "Reset" ] )
 
 	def __init__( self, color=imath.Color3f( 1 ), **kw ) :
 

python/GafferUI/Divider.py

@@ -34,15 +34,15 @@
 #
 ##########################################################################
 
-import IECore
+import enum
 
 import GafferUI
 
 from Qt import QtWidgets
 
 class Divider( GafferUI.Widget ) :
 
-	Orientation = IECore.Enum.create( "Vertical", "Horizontal" )
+	Orientation = enum.Enum( "Divider", [ "Vertical", "Horizontal" ] )
 
 	def __init__( self, orientation = Orientation.Horizontal, **kw ) :
 

python/GafferUI/Enums.py

@@ -34,7 +34,8 @@
 #
 ##########################################################################
 
-import IECore
+import enum
+
 import GafferUI
 
 from Qt import QtCore
@@ -44,7 +45,7 @@
 
 # HorizontalAlignment
 
-HorizontalAlignment = IECore.Enum.create( "None_", "Left", "Right", "Center", "Justify" )
+HorizontalAlignment = enum.Enum( "HorizontalAlignment", [ "None_", "Left", "Right", "Center", "Justify" ] )
 
 @staticmethod
 def __horizontalFromQt( a ) :
@@ -80,7 +81,7 @@ def __horizontalToQt( a ) :
 
 # VerticalAlignment
 
-VerticalAlignment = IECore.Enum.create( "None_", "Top", "Bottom", "Center" )
+VerticalAlignment = enum.Enum( "VerticalAlignment", [ "None_", "Top", "Bottom", "Center" ] )
 
 @staticmethod
 def __verticalFromQt( a ) :
@@ -112,11 +113,11 @@ def __verticalToQt( a ) :
 
 # Edge
 
-Edge = IECore.Enum.create( "Top", "Bottom", "Left", "Right" )
+Edge = enum.Enum( "Edge", [ "Top", "Bottom", "Left", "Right" ] )
 
 # Scroll Mode
 
-ScrollMode = IECore.Enum.create( "Never", "Always", "Automatic" )
+ScrollMode = enum.Enum( "ScrollMode", [ "Never", "Always", "Automatic" ] )
 
 __modesToPolicies = {
 	ScrollMode.Never : QtCore.Qt.ScrollBarAlwaysOff,
@@ -139,4 +140,4 @@ def __scrollModeFromQt ( a ):
 	return __policiesToModes[a]
 
 ScrollMode._fromQt = __scrollModeFromQt
-ScrollMode._toQt = __scrollModeToQt
+ScrollMode._toQt = __scrollModeToQt

python/GafferUI/EventLoop.py

@@ -35,6 +35,7 @@
 #
 ##########################################################################
 
+import enum
 import time
 import weakref
 import threading
@@ -53,7 +54,7 @@
 ## This class provides the event loops used to run GafferUI based applications.
 class EventLoop( object ) :
 
-	__RunStyle = IECore.Enum.create( "Normal", "PumpThread", "AlreadyRunning", "Houdini" )
+	__RunStyle = enum.Enum( "__RunStyle", [ "Normal", "PumpThread", "AlreadyRunning", "Houdini" ] )
 
 	## Creates a new EventLoop. Note that if you are creating the primary
 	# EventLoop for an application then you should use mainEventLoop() instead.

python/GafferUI/Frame.py

@@ -35,7 +35,7 @@
 #
 ##########################################################################
 
-import IECore
+import enum
 
 import GafferUI
 
@@ -44,7 +44,7 @@
 class Frame( GafferUI.ContainerWidget ) :
 
 	## \todo Raised and Inset?
-	BorderStyle = IECore.Enum.create( "None_", "Flat" )
+	BorderStyle = enum.Enum( "BorderStyle", [ "None_", "Flat" ] )
 
 	def __init__( self, child=None, borderWidth=8, borderStyle=BorderStyle.Flat, **kw ) :
 
@@ -61,7 +61,7 @@ def __init__( self, child=None, borderWidth=8, borderStyle=BorderStyle.Flat, **k
 
 	def setBorderStyle( self, borderStyle ) :
 
-		self._qtWidget().setProperty( "gafferBorderStyle", str( borderStyle ) )
+		self._qtWidget().setProperty( "gafferBorderStyle", borderStyle.name )
 
 	def getBorderStyle( self ) :