extmod/modure: Add match.groups() method, and tests.

This feature is controlled at compile time by MICROPY_PY_URE_MATCH_GROUPS,
disabled by default.

Thanks to @dmazzella for the original patch for this feature; see #3770.

extmod/modure.c

@@ -77,8 +77,28 @@ STATIC mp_obj_t match_group(mp_obj_t self_in, mp_obj_t no_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_2(match_group_obj, match_group);
 
+#if MICROPY_PY_URE_MATCH_GROUPS
+
+STATIC mp_obj_t match_groups(mp_obj_t self_in) {
+    mp_obj_match_t *self = MP_OBJ_TO_PTR(self_in);
+    if (self->num_matches <= 1) {
+        return mp_const_empty_tuple;
+    }
+    mp_obj_tuple_t *groups = MP_OBJ_TO_PTR(mp_obj_new_tuple(self->num_matches - 1, NULL));
+    for (int i = 1; i < self->num_matches; ++i) {
+        groups->items[i - 1] = match_group(self_in, MP_OBJ_NEW_SMALL_INT(i));
+    }
+    return MP_OBJ_FROM_PTR(groups);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(match_groups_obj, match_groups);
+
+#endif
+
 STATIC const mp_rom_map_elem_t match_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_group), MP_ROM_PTR(&match_group_obj) },
+    #if MICROPY_PY_URE_MATCH_GROUPS
+    { MP_ROM_QSTR(MP_QSTR_groups), MP_ROM_PTR(&match_groups_obj) },
+    #endif
 };
 
 STATIC MP_DEFINE_CONST_DICT(match_locals_dict, match_locals_dict_table);

py/mpconfig.h

@@ -1164,6 +1164,10 @@ typedef double mp_float_t;
 #define MICROPY_PY_URE (0)
 #endif
 
+#ifndef MICROPY_PY_URE_MATCH_GROUPS
+#define MICROPY_PY_URE_MATCH_GROUPS (0)
+#endif
+
 #ifndef MICROPY_PY_UHEAPQ
 #define MICROPY_PY_UHEAPQ (0)
 #endif

tests/extmod/ure_groups.py

@@ -0,0 +1,33 @@
+# test match.groups()
+
+try:
+    import ure as re
+except ImportError:
+    try:
+        import re
+    except ImportError:
+        print("SKIP")
+        raise SystemExit
+
+try:
+    m = re.match(".", "a")
+    m.groups
+except AttributeError:
+    print('SKIP')
+    raise SystemExit
+
+
+m = re.match(r'(([0-9]*)([a-z]*)[0-9]*)','1234hello567')
+print(m.groups())
+
+m = re.match(r'([0-9]*)(([a-z]*)([0-9]*))','1234hello567')
+print(m.groups())
+
+# optional group that matches
+print(re.match(r'(a)?b(c)', 'abc').groups())
+
+# optional group that doesn't match
+print(re.match(r'(a)?b(c)', 'bc').groups())
+
+# only a single match
+print(re.match(r'abc', 'abc').groups())