Use operator module to define binary operators on Python objects

This simplifies things considerably, as we don't need to worry about
checking for NotImplemented, using the reflected versions of each
method, or handling errors.

M2/Macaulay2/packages/Python.m2

@@ -272,33 +272,39 @@ PythonObject == PythonObject := (x, y) ->
 PythonObject == Thing := (x, y) -> x == toPython y
 Thing == PythonObject := (x, y) -> toPython x == y
 
-isimplemented = x -> value x@@"__class__"@@"__name__" != "NotImplementedType"
+getattr = method()
+getattr(PythonObject, String) := pythonObjectGetAttrString
+PythonObject @@ Thing := (x, y) -> getattr(x, toString y)
+
+hasattr = method()
+hasattr(PythonObject, String) := pythonObjectHasAttrString
+
+setattr = method()
+setattr(PythonObject, String, Thing) := (x, y, e) ->
+    pythonObjectSetAttrString(x, y, toPython e)
+PythonObject @@ Thing = (x, y, e) -> setattr(x, toString y, e)
+
+-- binary operators
+operator = import "operator"
 scan({
-	(symbol +, "add"),
-	(symbol -, "sub"),
-	(symbol *, "mul"),
-	(symbol @, "matmul"),
-	(symbol /, "truediv"),
-	(symbol //, "floordiv"),
-	(symbol %, "mod"),
-	(symbol ^, "pow"),
-	(symbol <<, "lshift"),
-	(symbol >>, "rshift"),
-	(symbol &, "and"),
-	(symbol |, "or"),
-	(symbol ^^, "xor"),
-	(symbol and, "and"),
-	(symbol or, "or"),
-	(symbol xor, "xor")},
-    (op, name) -> (
-	m := "__" | name | "__";
-	rm := "__r" | name | "__";
-	f := (x, y) -> (
-	    local r;
-	    if hasattr(x, m)  and isimplemented(r = x@@m  y) then r else
-	    if hasattr(y, rm) and isimplemented(r = y@@rm x) then r else
-	    error("no method for ", format toString op));
-	installMethod(op, PythonObject, PythonObject, f);
+	(symbol +,   operator@@"add"),
+	(symbol -,   operator@@"sub"),
+	(symbol *,   operator@@"mul"),
+	(symbol @,   operator@@"matmul"),
+	(symbol /,   operator@@"truediv"),
+	(symbol //,  operator@@"floordiv"),
+	(symbol %,   operator@@"mod"),
+	(symbol ^,   operator@@"pow"),
+	(symbol <<,  operator@@"lshift"),
+	(symbol >>,  operator@@"rshift"),
+	(symbol &,   operator@@"and_"),
+	(symbol |,   operator@@"or_"),
+	(symbol ^^,  operator@@"xor"),
+	(symbol and, operator@@"and_"),
+	(symbol or,  operator@@"or_"),
+	(symbol xor, operator@@"xor")},
+    (op, f) -> (
+	installMethod(op, PythonObject, PythonObject, toFunction f);
 	installMethod(op, PythonObject, Thing, (x, y) -> f(x, toPython y));
 	installMethod(op, Thing, PythonObject, (x, y) -> f(toPython x, y))
 	)
@@ -348,18 +354,6 @@ setitem(PythonObject, Thing, Thing) := (x, i, e) -> (
     null)
 PythonObject_Thing = setitem
 
-getattr = method()
-getattr(PythonObject, String) := pythonObjectGetAttrString
-PythonObject @@ Thing := (x, y) -> getattr(x, toString y)
-
-hasattr = method()
-hasattr(PythonObject, String) := pythonObjectHasAttrString
-
-setattr = method()
-setattr(PythonObject, String, Thing) := (x, y, e) ->
-    pythonObjectSetAttrString(x, y, toPython e)
-PythonObject @@ Thing = (x, y, e) -> setattr(x, toString y, e)
-
 isMember(Thing,        PythonObject) := (x, y) -> false
 isMember(PythonObject, PythonObject) := (x, y) -> value y@@"__contains__" x