Add object.__str__ and object.__repr__

Before, the default behavior (falling back to __repr__ if __str__ doesn't
exist, and giving a default representation if __repr__ doesn't exist) was
provided by the repr() and str() functions.

src/runtime/objmodel.cpp

@@ -1094,17 +1094,10 @@ extern "C" BoxedString* str(Box* obj) {
 
     if (obj->cls != str_cls) {
         Box* str = getclsattr_internal(obj, "__str__", NULL);
-        if (str == NULL)
-            str = getclsattr_internal(obj, "__repr__", NULL);
-
-        if (str == NULL) {
-            char buf[80];
-            snprintf(buf, 80, "<%s object at %p>", getTypeName(obj)->c_str(), obj);
-            return boxStrConstant(buf);
-        } else {
-            obj = runtimeCallInternal0(str, NULL, ArgPassSpec(0));
-        }
+        assert(str); // TODO clean the rest of this up now that this assert is true
+        obj = runtimeCallInternal0(str, NULL, ArgPassSpec(0));
     }
+
     if (obj->cls != str_cls) {
         fprintf(stderr, "__str__ did not return a string!\n");
         abort();
@@ -1117,19 +1110,8 @@ extern "C" Box* repr(Box* obj) {
     slowpath_repr.log();
 
     Box* repr = getclsattr_internal(obj, "__repr__", NULL);
-    if (repr == NULL) {
-        ASSERT(isUserDefined(obj->cls), "%s", getTypeName(obj)->c_str());
-
-        char buf[80];
-        if (obj->cls == type_cls) {
-            snprintf(buf, 80, "<type '%s'>", getNameOfClass(static_cast<BoxedClass*>(obj))->c_str());
-        } else {
-            snprintf(buf, 80, "<%s object at %p>", getTypeName(obj)->c_str(), obj);
-        }
-        return boxStrConstant(buf);
-    } else {
-        obj = runtimeCall0(repr, ArgPassSpec(0));
-    }
+    assert(repr);
+    obj = runtimeCall0(repr, ArgPassSpec(0));
 
     if (obj->cls != str_cls) {
         raiseExcHelper(TypeError, "__repr__ did not return a string!");

src/runtime/types.cpp

@@ -487,6 +487,21 @@ Box* objectInit(Box* b, BoxedTuple* args) {
     return None;
 }
 
+Box* objectRepr(Box* obj) {
+    char buf[80];
+    if (obj->cls == type_cls) {
+        snprintf(buf, 80, "<type '%s'>", getNameOfClass(static_cast<BoxedClass*>(obj))->c_str());
+    } else {
+        snprintf(buf, 80, "<%s object at %p>", getTypeName(obj)->c_str(), obj);
+    }
+    return boxStrConstant(buf);
+}
+
+Box* objectStr(Box* obj) {
+    static const std::string repr_str("__repr__");
+    return callattrInternal(obj, &repr_str, CLASS_ONLY, NULL, ArgPassSpec(0), NULL, NULL, NULL, NULL, NULL);
+}
+
 bool TRACK_ALLOCATIONS = false;
 void setupRuntime() {
     root_hcls = HiddenClass::makeRoot();
@@ -556,6 +571,8 @@ void setupRuntime() {
     object_cls->giveAttr("__name__", boxStrConstant("object"));
     object_cls->giveAttr("__new__", new BoxedFunction(boxRTFunction((void*)objectNew, UNKNOWN, 1, 0, true, false)));
     object_cls->giveAttr("__init__", new BoxedFunction(boxRTFunction((void*)objectInit, UNKNOWN, 1, 0, true, false)));
+    object_cls->giveAttr("__repr__", new BoxedFunction(boxRTFunction((void*)objectRepr, UNKNOWN, 1, 0, false, false)));
+    object_cls->giveAttr("__str__", new BoxedFunction(boxRTFunction((void*)objectStr, UNKNOWN, 1, 0, false, false)));
     object_cls->freeze();
 
     auto typeCallObj = boxRTFunction((void*)typeCall, UNKNOWN, 1, 0, true, false);

test/tests/str_default.py

+class C(object):
+    def __repr__(self):
+        print "repr"
+        return 1
+
+c = C()
+print "C object" in object.__repr__(c)
+print object.__str__(c)
+
+print c.__repr__()
+print c.__str__()