dict.__delitem__, and fix a bug where delitems weren't interacting with exceptions properly

src/codegen/irgen/irgenerator.cpp

@@ -1436,8 +1436,7 @@ private:
 
             emitter.createPatchpoint(pp, (void*)pyston::delitem, llvm_args, exc_info);
         } else {
-            emitter.getBuilder()->CreateCall2(g.funcs.delitem, converted_target->getValue(),
-                                              converted_slice->getValue());
+            emitter.createCall2(exc_info, g.funcs.delitem, converted_target->getValue(), converted_slice->getValue());
         }
 
         converted_target->decvref(emitter);

src/runtime/dict.cpp

@@ -119,6 +119,24 @@ Box* dictSetitem(BoxedDict* self, Box* k, Box* v) {
     return None;
 }
 
+Box* dictDelitem(BoxedDict* self, Box* k) {
+    assert(self->cls == dict_cls);
+
+    auto it = self->d.find(k);
+    if (it == self->d.end()) {
+        BoxedString* s = reprOrNull(k);
+
+        if (s)
+            raiseExcHelper(KeyError, "%s", s->s.c_str());
+        else
+            raiseExcHelper(KeyError, "");
+    }
+
+    self->d.erase(it);
+
+    return None;
+}
+
 Box* dictPop(BoxedDict* self, Box* k, Box* d) {
     assert(self->cls == dict_cls);
 
@@ -268,6 +286,7 @@ void setupDict() {
 
     dict_cls->giveAttr("__getitem__", new BoxedFunction(boxRTFunction((void*)dictGetitem, UNKNOWN, 2)));
     dict_cls->giveAttr("__setitem__", new BoxedFunction(boxRTFunction((void*)dictSetitem, NONE, 3)));
+    dict_cls->giveAttr("__delitem__", new BoxedFunction(boxRTFunction((void*)dictDelitem, UNKNOWN, 2)));
     dict_cls->giveAttr("__contains__", new BoxedFunction(boxRTFunction((void*)dictContains, BOXED_BOOL, 2)));
 
     dict_cls->giveAttr("__nonzero__", new BoxedFunction(boxRTFunction((void*)dictNonzero, BOXED_BOOL, 1)));

test/tests/dict.py

@@ -72,29 +72,32 @@ print sorted(dict((('a', 1), ('b', 2)), b=3)) == sorted(dict((['a', 1], ('b', 3)
 try:
     print dict([1,2], [2,3])
 except TypeError, e:
-    print 'dict expected at most 1 arg'
-else:
-    raise
+    print e
 
 try:
     print dict([(1,2), 42])
 except TypeError, e:
-    print 'cannot convert dictionary update sequence element #1 to a sequence'
-else:
-    raise
+    print e
 
 try:
     # invalid tuple len
     print dict([(10,20), (1,2,3)])
-except TypeError, e:
-    print 'dictionary update sequence element #1 has length 3; 2 is required'
-else:
-    raise
+except ValueError, e:
+    print e
 
 try:
     # invalid list len
     print dict([[10,20], [1,2,3]])
-except TypeError, e:
-    print 'dictionary update sequence element #1 has length 3; 2 is required'
-else:
-    raise
+except ValueError, e:
+    print e
+
+d = {i:i**2 for i in xrange(10)}
+print sorted(d.items())
+del d[2]
+print d.__delitem__(4)
+print sorted(d.items())
+
+try:
+    del d[2]
+except KeyError, e:
+    print e