py: Allow keyword arguments for namedtuple

py/objnamedtuple.c

@@ -89,9 +89,39 @@ STATIC mp_obj_t namedtuple_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_
         // Counts include implicit "self"
         nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                                                "__new__() takes %d positional arguments but %d were given",
-                                               num_fields + 1, n_args + 1));
+                                               num_fields + 1, n_args + n_kw + 1));
     }
-    mp_obj_tuple_t *tuple = mp_obj_new_tuple(n_args, args);
+
+    mp_obj_t *arg_objects;
+    if (n_args == num_fields) {
+        arg_objects = (mp_obj_t*)args;
+    } else {
+        size_t alloc_size = sizeof(mp_obj_t) * num_fields;
+        arg_objects = alloca(alloc_size);
+        memset(arg_objects, 0, alloc_size);
+
+        for (mp_uint_t i = 0; i < n_args; i++) {
+            arg_objects[i] = args[i];
+        }
+
+        for (mp_uint_t i = n_args; i < n_args + 2 * n_kw; i += 2) {
+            qstr kw = MP_OBJ_QSTR_VALUE(args[i]);
+            int id = namedtuple_find_field(type, kw);
+            if (id == -1) {
+                nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
+                            "__new__() got an unexpected keyword argument '%s'",
+                            qstr_str(kw)));
+            }
+            if (arg_objects[id] != NULL) {
+                nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
+                            "__new__() got multiple values for argument '%s'",
+                            qstr_str(kw)));
+            }
+            arg_objects[id] = args[i + 1];
+        }
+    }
+
+    mp_obj_tuple_t *tuple = mp_obj_new_tuple(num_fields, arg_objects);
     tuple->base.type = type_in;
     return tuple;
 }

tests/basics/namedtuple1.py

@@ -6,19 +6,19 @@ except ImportError:
 T = namedtuple("Tup", ["foo", "bar"])
 # CPython prints fully qualified name, what we don't bother to do so far
 #print(T)
-t = T(1, 2)
-print(t)
-print(t[0], t[1])
-print(t.foo, t.bar)
+for t in T(1, 2), T(bar=1, foo=2):
+    print(t)
+    print(t[0], t[1])
+    print(t.foo, t.bar)
 
-print(len(t))
-print(bool(t))
-print(t + t)
-print(t * 3)
+    print(len(t))
+    print(bool(t))
+    print(t + t)
+    print(t * 3)
 
-print([f for f in t])
+    print([f for f in t])
 
-print(isinstance(t, tuple))
+    print(isinstance(t, tuple))
 
 try:
     t[0] = 200
@@ -39,6 +39,16 @@ try:
 except TypeError:
     print("TypeError")
 
+try:
+    t = T(foo=1)
+except TypeError:
+    print("TypeError")
+
+try:
+    t = T(1, foo=1)
+except TypeError:
+    print("TypeError")
+
 # Try single string
 # Not implemented so far
 #T3 = namedtuple("TupComma", "foo bar")