re: Add support for `finditer` method.

docs/library/re.rst

@@ -140,6 +140,12 @@ Functions
 
    Note: availability of this function depends on :term:`MicroPython port`.
 
+.. function:: finditer(regex_str, string)
+
+    Return an iterator yielding ``Match`` objects over all non-overlapping
+    matches for the RE *regex_str* in *string*. The string is scanned
+    left-to-right, and matches are returned in the order found.
+
 .. data:: DEBUG
 
    Flag value, display debug information about compiled expression.
@@ -156,10 +162,11 @@ Compiled regular expression. Instances of this class are created using
 
 .. method:: regex.match(string, [pos, [endpos]])
             regex.search(string, [pos, [endpos]])
+            regex.finditer(string, [pos, [endpos]])
             regex.sub(replace, string, count=0, flags=0, /)
 
-   Similar to the module-level functions :meth:`match`, :meth:`search`
-   and :meth:`sub`.
+   Similar to the module-level functions :meth:`match`, :meth:`search`,
+   :meth:`finditer`, and :meth:`sub`.
    Using methods is (much) more efficient if the same regex is applied to
    multiple strings.
 

extmod/modre.c

@@ -422,11 +422,75 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_sub_obj, 3, 5, re_sub_helper);
 
 #endif
 
+#if MICROPY_PY_RE_FINDITER
+
+typedef struct _mp_re_finditer_it_t {
+    mp_obj_base_t base;
+    mp_fun_1_t iternext;
+    mp_obj_t pattern;
+    mp_obj_t str;
+    mp_obj_t start;
+    mp_obj_t end;
+} mp_re_finditer_it_t;
+
+
+static mp_obj_t mp_re_finditer_it_iternext(mp_obj_t self_in) {
+    mp_re_finditer_it_t *self = MP_OBJ_TO_PTR(self_in);
+
+    mp_obj_t args[4] = {
+        self->pattern,
+        self->str,
+        self->start,
+        self->end
+    };
+    int n_args = (self->end == mp_const_none) ? 3 : 4;
+
+    mp_obj_t obj_match = re_exec(false, n_args, args);
+    if (obj_match == mp_const_none) {
+        return MP_OBJ_STOP_ITERATION;
+    }
+
+    mp_obj_match_t *match = MP_OBJ_TO_PTR(obj_match);
+    const char *begin = mp_obj_str_get_str(self->str);
+    self->start = MP_OBJ_NEW_SMALL_INT(match->caps[1] - begin);
+    return obj_match;
+}
+
+static mp_obj_t re_finditer(size_t n_args, const mp_obj_t *args) {
+    mp_re_finditer_it_t *iter = mp_obj_malloc(mp_re_finditer_it_t, &mp_type_polymorph_iter);
+    iter->iternext = mp_re_finditer_it_iternext;
+    iter->str = args[1];
+    iter->start = MP_OBJ_NEW_SMALL_INT(0);
+    iter->end = mp_const_none;
+
+    if (mp_obj_is_type(args[0], (mp_obj_type_t *)&re_type)) {
+        iter->pattern = args[0];
+        if (n_args > 2) {
+            iter->start = args[2];
+            if (n_args > 3) {
+                iter->end = args[3];
+            }
+        }
+    }
+    else {
+        iter->pattern = mod_re_compile(1, args);
+    }
+
+    return MP_OBJ_FROM_PTR(iter);
+}
+
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_finditer_obj, 2, 4, re_finditer);
+
+#endif // MICROPY_PY_RE_FINDITER
+
 #if !MICROPY_ENABLE_DYNRUNTIME
 static const mp_rom_map_elem_t re_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_match), MP_ROM_PTR(&re_match_obj) },
     { MP_ROM_QSTR(MP_QSTR_search), MP_ROM_PTR(&re_search_obj) },
     { MP_ROM_QSTR(MP_QSTR_split), MP_ROM_PTR(&re_split_obj) },
+    #if MICROPY_PY_RE_FINDITER
+    { MP_ROM_QSTR(MP_QSTR_finditer), MP_ROM_PTR(&re_finditer_obj) },
+    #endif
     #if MICROPY_PY_RE_SUB
     { MP_ROM_QSTR(MP_QSTR_sub), MP_ROM_PTR(&re_sub_obj) },
     #endif
@@ -477,6 +541,9 @@ static const mp_rom_map_elem_t mp_module_re_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_compile), MP_ROM_PTR(&mod_re_compile_obj) },
     { MP_ROM_QSTR(MP_QSTR_match), MP_ROM_PTR(&re_match_obj) },
     { MP_ROM_QSTR(MP_QSTR_search), MP_ROM_PTR(&re_search_obj) },
+    #if MICROPY_PY_RE_FINDITER
+    { MP_ROM_QSTR(MP_QSTR_finditer), MP_ROM_PTR(&re_finditer_obj) },
+    #endif
     #if MICROPY_PY_RE_SUB
     { MP_ROM_QSTR(MP_QSTR_sub), MP_ROM_PTR(&re_sub_obj) },
     #endif

py/mpconfig.h

@@ -1652,6 +1652,10 @@ typedef double mp_float_t;
 #define MICROPY_PY_RE_MATCH_SPAN_START_END (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EVERYTHING)
 #endif
 
+#ifndef MICROPY_PY_RE_FINDITER
+#define MICROPY_PY_RE_FINDITER (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
+#endif
+
 #ifndef MICROPY_PY_RE_SUB
 #define MICROPY_PY_RE_SUB (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
 #endif

tests/extmod/re_finditer.py

@@ -0,0 +1,25 @@
+try:
+    import re
+    from re import finditer
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+ms = re.finditer(r'f[a-z]*', 'which foot or hand fell fastest')
+print(list(x.group(0) for x in ms))
+
+p = re.compile(r'f[a-z]*')
+ms = p.finditer('which foot or hand fell fastest')
+print(list(x.group(0) for x in ms))
+
+ms = p.finditer('which foot or hand fell fastest', 10)
+print(list(x.group(0) for x in ms))
+
+ms = p.finditer('which foot or hand fell fastest', 10, 21)
+print(list(x.group(0) for x in ms))
+
+ms = re.finditer(r'\s+', 'which foot or hand fell fastest')
+print(list(x.group(0) for x in ms))
+
+ms = re.finditer(r'zz', 'which foot or hand fell fastest')
+print(list(x.group(0) for x in ms))