Add PyTypeObjectWrapper#<=>

Author: mrkn

lib/pycall/pytypeobject_wrapper.rb

@@ -60,6 +60,24 @@ def subclass?(other)
       end
     end
 
+    def <=>(other)
+      return 0  if equal?(other)
+      case other
+      when PyTypeObjectWrapper
+        return super if __pyptr__ == other.__pyptr__
+        other = other.__pyptr__
+      when Class, Module
+        return -1 if subclass?(other)
+        return 1  if other > self
+      end
+
+      return nil unless other.is_a?(PyTypePtr)
+      return 0  if __pyptr__ == other
+      return -1 if __pyptr__.subclass?(other)
+      return 1  if other.subclass?(__pyptr__)
+      nil
+    end
+
     private
 
     def register_python_type_mapping

spec/pycall/pytypeobject_wrapper_spec.rb

@@ -41,6 +41,79 @@ module PyCall
       end
     end
 
+    describe '#<=>(other)' do
+      context 'when the value of other is a PyTypeObjectWrapper' do
+        context 'when the given class is a superclass in Python of the receiver' do
+          it 'returns -1' do
+            expect(PyCall.builtins.list <=> PyCall.builtins.object).to eq(-1)
+          end
+        end
+
+        context 'when the given class is a subclass in Python of the receiver' do
+          it 'returns 1' do
+            expect(PyCall.builtins.object <=> PyCall.builtins.list).to eq(1)
+          end
+        end
+
+        context 'when the given class is the receiver' do
+          it 'returns 0' do
+            expect(PyCall.builtins.list <=> PyCall.builtins.list).to eq(0)
+          end
+        end
+      end
+
+      context 'when the value of other is a PyTypePtr' do
+        context 'when the given class is a superclass in Python of the receiver' do
+          it 'returns -1' do
+            expect(PyCall.builtins.list <=> PyCall.builtins.object.__pyptr__).to eq(-1)
+          end
+        end
+
+        context 'when the given class is a subclass in Python of the receiver' do
+          it 'returns 1' do
+            expect(PyCall.builtins.object <=> PyCall.builtins.list.__pyptr__).to eq(1)
+          end
+        end
+
+        context 'when the given class is the receiver' do
+          it 'returns 0' do
+            expect(PyCall.builtins.list <=> PyCall.builtins.list.__pyptr__).to eq(0)
+          end
+        end
+      end
+
+      context 'when the value of other is a Class' do
+        context 'when the given class is a superclass of the receiver' do
+          it 'returns -1' do
+            expect(PyCall.builtins.list <=> Object).to eq(-1)
+            expect(PyCall.builtins.list <=> PyObjectWrapper).to eq(-1)
+          end
+        end
+
+        context 'when the given class is a subclass of the receiver' do
+          let(:subclass) { Class.new(PyCall.builtins.list) }
+
+          it 'returns 1' do
+            expect(PyCall.builtins.list <=> subclass).to eq(1)
+          end
+        end
+
+        context 'when the given class is neither a superclass or a subclass of the receiver' do
+          it 'returns nil' do
+            expect(PyCall.builtins.list <=> PyTypeObjectWrapper).to eq(nil)
+            expect(PyCall.builtins.list <=> Array).to eq(nil)
+          end
+        end
+      end
+
+      context 'when the other cases' do
+        it 'returns nil' do
+          expect(PyCall.builtins.list <=> Conversion.from_ruby(42)).to eq(nil)
+          expect(PyCall.builtins.list <=> 42).to eq(nil)
+        end
+      end
+    end
+
     describe '#===' do
       specify do
         expect(PyCall.builtins.tuple === PyCall.tuple()).to eq(true)