objsingleton: New home for Ellipsis and NotImplemented.

Having NotImplemented as MP_OBJ_SENTINEL turned out to be problematic
(it needs to be checked for in a lot of places, otherwise it'll crash
as would pass MP_OBJ_IS_OBJ()), so made a proper singleton value like
Ellipsis, both of them sharing the same type.

1 files changed, 57 insertions, 0 deletions

diff --git a/py/objsingleton.c b/py/objsingleton.c
new file mode 100644
index 000000000..23a5cd4d6
--- /dev/null
+++ b/py/objsingleton.c
@@ -0,0 +1,57 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013, 2014 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+
+#include "py/nlr.h"
+#include "py/obj.h"
+#include "py/runtime0.h"
+
+/******************************************************************************/
+/* singleton objects defined by Python                                        */
+
+typedef struct _mp_obj_singleton_t {
+    mp_obj_base_t base;
+    qstr name;
+} mp_obj_singleton_t;
+
+STATIC void singleton_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
+    (void)kind;
+    mp_obj_singleton_t *self = self_in;
+    mp_printf(print, "%q", self->name);
+}
+
+const mp_obj_type_t mp_type_singleton = {
+    { &mp_type_type },
+    .name = MP_QSTR_,
+    .print = singleton_print,
+};
+
+const mp_obj_singleton_t mp_const_ellipsis_obj = {{&mp_type_singleton}, MP_QSTR_Ellipsis};
+#if MICROPY_PY_BUILTINS_NOTIMPLEMENTED
+const mp_obj_singleton_t mp_const_notimplemented_obj = {{&mp_type_singleton}, MP_QSTR_NotImplemented};
+#endif