py: Add attrtuple object, for space-efficient tuples with attr access.

If you need the functionality of a namedtuple but will only make 1 or a
few instances, then use an attrtuple instead.

1 files changed, 94 insertions, 0 deletions

diff --git a/py/objattrtuple.c b/py/objattrtuple.c
new file mode 100644
index 0000000000..223c4c5810
--- /dev/null
+++ b/py/objattrtuple.c
@@ -0,0 +1,94 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015 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 "py/objtuple.h"
+
+#if MICROPY_PY_ATTRTUPLE || MICROPY_PY_COLLECTIONS
+
+// this helper function is used by collections.namedtuple
+#if !MICROPY_PY_COLLECTIONS
+STATIC
+#endif
+void mp_obj_attrtuple_print_helper(const mp_print_t *print, const qstr *fields, mp_obj_tuple_t *o) {
+    mp_print_str(print, "(");
+    for (mp_uint_t i = 0; i < o->len; i++) {
+        if (i > 0) {
+            mp_print_str(print, ", ");
+        }
+        mp_printf(print, "%q=", fields[i]);
+        mp_obj_print_helper(print, o->items[i], PRINT_REPR);
+    }
+    mp_print_str(print, ")");
+}
+
+#endif
+
+#if MICROPY_PY_ATTRTUPLE
+
+STATIC void mp_obj_attrtuple_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
+    (void)kind;
+    mp_obj_tuple_t *o = o_in;
+    const qstr *fields = (const qstr*)o->items[o->len];
+    mp_obj_attrtuple_print_helper(print, fields, o);
+}
+
+STATIC void mp_obj_attrtuple_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
+    if (dest[0] == MP_OBJ_NULL) {
+        // load attribute
+        mp_obj_tuple_t *self = self_in;
+        mp_uint_t len = self->len;
+        const qstr *fields = (const qstr*)self->items[len];
+        for (mp_uint_t i = 0; i < len; i++) {
+            if (fields[i] == attr) {
+                dest[0] = self->items[i];
+                return;
+            }
+        }
+    }
+}
+
+mp_obj_t mp_obj_new_attrtuple(const qstr *fields, mp_uint_t n, const mp_obj_t *items) {
+    mp_obj_tuple_t *o = mp_obj_new_tuple(n + 1, NULL);
+    o->base.type = &mp_type_attrtuple;
+    for (mp_uint_t i = 0; i < n; i++) {
+        o->items[i] = items[i];
+    }
+    o->items[n] = (void*)fields;
+    return o;
+}
+
+const mp_obj_type_t mp_type_attrtuple = {
+    { &mp_type_type },
+    .name = MP_QSTR_tuple, // reuse tuple to save on a qstr
+    .print = mp_obj_attrtuple_print,
+    .unary_op = mp_obj_tuple_unary_op,
+    .binary_op = mp_obj_tuple_binary_op,
+    .attr = mp_obj_attrtuple_attr,
+    .subscr = mp_obj_tuple_subscr,
+    .getiter = mp_obj_tuple_getiter,
+};
+
+#endif // MICROPY_PY_ATTRTUPLE