builtin: Implement delattr (#55)

Author: corona10

builtin/builtin.go

@@ -29,7 +29,7 @@ func init() {
 		// py.MustNewMethod("callable", builtin_callable, 0, callable_doc),
 		py.MustNewMethod("chr", builtin_chr, 0, chr_doc),
 		py.MustNewMethod("compile", builtin_compile, 0, compile_doc),
-		// py.MustNewMethod("delattr", builtin_delattr, 0, delattr_doc),
+		py.MustNewMethod("delattr", builtin_delattr, 0, delattr_doc),
 		// py.MustNewMethod("dir", builtin_dir, 0, dir_doc),
 		py.MustNewMethod("divmod", builtin_divmod, 0, divmod_doc),
 		py.MustNewMethod("eval", py.InternalMethodEval, 0, eval_doc),
@@ -633,6 +633,27 @@ func source_as_string(cmd py.Object, funcname, what string /*, PyCompilerFlags *
 	// 	return nil;
 }
 
+const delattr_doc = `Deletes the named attribute from the given object.
+
+delattr(x, 'y') is equivalent to  "del x.y"
+`
+
+func builtin_delattr(self py.Object, args py.Tuple) (py.Object, error) {
+	var v py.Object
+	var name py.Object
+
+	err := py.UnpackTuple(args, nil, "delattr", 2, 2, &v, &name)
+	if err != nil {
+		return nil, err
+	}
+
+	err = py.DeleteAttr(v, name)
+	if err != nil {
+		return nil, err
+	}
+	return py.None, nil
+}
+
 const compile_doc = `compile(source, filename, mode[, flags[, dont_inherit]]) -> code object
 
 Compile the source string (a Python module, statement or expression)

builtin/tests/builtin.py

@@ -300,6 +300,15 @@ class C: pass
 setattr(c, "potato", "spud")
 assert getattr(c, "potato") == "spud"
 assert c.potato == "spud"
+delattr(c, "potato")
+assert not hasattr(c, "potato")
+ok = False
+try:
+    delattr(c, "potato")
+except AttributeError as e:
+    ok = True
+finally:
+    assert ok
 
 doc="sum"
 assert sum([1,2,3]) == 6