Make generator protocol interface and adjust generator.go to use it

Author: ncw

py/generator.go

@@ -76,7 +76,7 @@ func (it *Generator) M__next__() Object{
 // without yielding another value. When send() is called to start the
 // generator, it must be called with None as the argument, because
 // there is no yield expression that could receive the value.
-func (it*Generator) Send(valueObject){
+func (it*Generator) Send(valueObject) Object{
 panic("generator send not implemented")
 }
 
@@ -88,7 +88,7 @@ func (it *Generator) Send(value Object){
 // StopIteration exception is raised. If the generator function does
 // not catch the passed-in exception, or raises a different exception,
 // then that exception propagates to the caller.
-func (it*Generator) Throw(argsTuple, kwargsStringDict){
+func (it*Generator) Throw(argsTuple, kwargsStringDict) Object{
 panic("generator throw not implemented")
 }
 
@@ -102,9 +102,9 @@ func (it *Generator) Throw(args Tuple, kwargs StringDict){
 // generator raises any other exception, it is propagated to the
 // caller. close() does nothing if the generator has already exited
 // due to an exception or normal exit.
-func (it*Generator) Close(){
+func (it*Generator) Close() Object{
 panic("generator close not implemented")
 }
 
 // Check interface is satisfied
-var_I_iterator= (*Generator)(nil)
+var_I_generator= (*Generator)(nil)

py/internal.go

@@ -247,3 +247,15 @@ func Next(self Object) Object{
 // FIXME should be TypeError
 panic(fmt.Sprintf("TypeError: '%s' object is not iterable", self.Type().Name))
 }
+
+// Call send for the python object
+funcSend(self, valueObject) Object{
+ifI, ok:=self.(I_send); ok{
+returnI.Send(value)
+ } elseifres, ok:=TypeCall1(self, "send", value); ok{
+returnres
+ }
+
+// FIXME should be TypeError
+panic(fmt.Sprintf("TypeError: '%s' object doesn't have send method", self.Type().Name))
+}

py/py.go

@@ -560,6 +560,25 @@ type I_iterator interface{
 I__next__
 }
 
+// Generator interfaces
+typeI_sendinterface{
+Send(valueObject) Object
+}
+typeI_throwinterface{
+Throw(argsTuple, kwargsStringDict) Object
+}
+typeI_closeinterface{
+Close() Object
+}
+
+// Interface all generators must satisfy
+typeI_generatorinterface{
+I_iterator
+I_send
+I_throw
+I_close
+}
+
 // Called (if present) by the reversed() built-in to implement reverse
 // iteration. It should return a new iterator object that iterates
 // over all the objects in the container in reverse order.