added enumerate()

1 files changed, 53 insertions, 0 deletions

diff --git a/py/objenumerate.c b/py/objenumerate.c
new file mode 100644
index 000000000..5bfd8a337
--- /dev/null
+++ b/py/objenumerate.c
@@ -0,0 +1,53 @@
+#include <stdlib.h>
+#include <assert.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "obj.h"
+#include "runtime.h"
+
+typedef struct _mp_obj_enumerate_t {
+    mp_obj_base_t base;
+    mp_obj_t iter;
+    machine_int_t cur;
+} mp_obj_enumerate_t;
+
+static mp_obj_t enumerate_getiter(mp_obj_t self_in) {
+    return self_in;
+}
+
+static mp_obj_t enumerate_iternext(mp_obj_t self_in);
+
+/* TODO: enumerate is one of the ones that can take args or kwargs.
+   Sticking to args for now */
+static mp_obj_t enumerate_make_new(mp_obj_t type_in, int n_args, const mp_obj_t *args) {
+    /* NOTE: args are backwards */
+    assert(n_args > 0);
+    args += n_args - 1;
+    mp_obj_enumerate_t *o = m_new_obj(mp_obj_enumerate_t);
+    o->base.type = &enumerate_type;
+    o->iter = rt_getiter(args[0]);
+    o->cur = n_args > 1 ? mp_obj_get_int(args[-1]) : 0;
+
+    return o;
+}
+
+const mp_obj_type_t enumerate_type = {
+    { &mp_const_type },
+    "enumerate",
+    .make_new = enumerate_make_new,
+    .iternext = enumerate_iternext,
+    .getiter = enumerate_getiter,
+};
+
+static mp_obj_t enumerate_iternext(mp_obj_t self_in) {
+    assert(MP_OBJ_IS_TYPE(self_in, &enumerate_type));
+    mp_obj_enumerate_t *self = self_in;
+    mp_obj_t next = rt_iternext(self->iter);
+    if (next == mp_const_stop_iteration) {
+        return mp_const_stop_iteration;
+    } else {
+        mp_obj_t items[] = {MP_OBJ_NEW_SMALL_INT(self->cur++), next};
+        return mp_obj_new_tuple(2, items);
+    }
+}