✨ Add {m} and {n,m} in PythonRegex

Author: Aunsiels

Diff for: pyformlang/regular_expression/python_regex.py

@@ -176,7 +176,7 @@ def _recombine(regex_to_recombine):
             if regex_to_recombine[idx] == "\\x" and idx < len(regex_to_recombine) - 2 \
                     and regex_to_recombine[idx + 1] in HEXASTRING \
                     and regex_to_recombine[idx + 2] in HEXASTRING:
-                next_str = "".join(regex_to_recombine[idx+1:idx+3])
+                next_str = "".join(regex_to_recombine[idx + 1:idx + 3])
                 s_trans = chr(int(next_str, 16))
                 temp.append(TRANSFORMATIONS.get(s_trans, s_trans))
                 idx += 3
@@ -197,12 +197,12 @@ def _recombine(regex_to_recombine):
                 temp.append(TRANSFORMATIONS.get(name, name))
                 idx = idx_end + 1
             elif regex_to_recombine[idx] == "\\u":
-                unicode_str = "".join(regex_to_recombine[idx+1: idx+5])
+                unicode_str = "".join(regex_to_recombine[idx + 1: idx + 5])
                 decoded = chr(int(unicode_str, 16))
                 temp.append(TRANSFORMATIONS.get(decoded, decoded))
                 idx = idx + 5
             elif regex_to_recombine[idx] == "\\U":
-                unicode_str = "".join(regex_to_recombine[idx+1: idx+9])
+                unicode_str = "".join(regex_to_recombine[idx + 1: idx + 9])
                 decoded = chr(int(unicode_str, 16))
                 temp.append(TRANSFORMATIONS.get(decoded, decoded))
                 idx = idx + 9
@@ -291,8 +291,71 @@ def _preprocess_positive_closure(self):
                 for j in range(pos_opening, len(regex_temp)):
                     regex_temp.append(regex_temp[j])
                 regex_temp.append("*")
+        regex_temp = self._add_repetition(regex_temp)
         self._python_regex = "".join(regex_temp)
 
+    @staticmethod
+    def _is_repetition(regex_list, idx):
+        if regex_list[idx] == "{":
+            end = idx
+            for i in range(idx + 1, len(regex_list)):
+                if regex_list[i] == "}":
+                    end = i
+                    break
+            inner = "".join(regex_list[idx + 1:end])
+            if "," in inner:
+                split = inner.split(",")
+                if len(split) != 2 or not split[0].isdigit() or not split[1].isdigit():
+                    return None
+                return int(split[0]), int(split[1]), end
+            if inner.isdigit():
+                return int(inner), end
+        return None
+
+    @staticmethod
+    def _find_repeated_sequence(regex_list):
+        if regex_list[-1] != ")":
+            return [regex_list[-1]]
+        res = [")"]
+        counter = -1
+        for i in range(len(regex_list) - 2, -1, -1):
+            if regex_list[i] == "(":
+                counter += 1
+                res.append("(")
+                if counter == 0:
+                    return res[::-1]
+            elif regex_list[i] == ")":
+                counter -= 1
+                res.append(")")
+            else:
+                res.append(regex_list[i])
+        return []
+
+    def _add_repetition(self, regex_list):
+        res = []
+        idx = 0
+        while idx < len(regex_list):
+            rep = self._is_repetition(regex_list, idx)
+            if rep is None:
+                res.append(regex_list[idx])
+                idx += 1
+            elif len(rep) == 2:
+                n_rep, end = rep
+                repeated = self._find_repeated_sequence(res)
+                for _ in range(n_rep - 1):
+                    res.extend(repeated)
+                idx = end + 1
+            elif len(rep) == 3:
+                min_rep, max_rep, end = rep
+                repeated = self._find_repeated_sequence(res)
+                for _ in range(min_rep - 1):
+                    res.extend(repeated)
+                for _ in range(min_rep, max_rep):
+                    res.extend(repeated)
+                    res.append("?")
+                idx = end + 1
+        return res
+
     def _preprocess_optional(self):
         regex_temp = []
         for symbol in self._python_regex:

Diff for: pyformlang/regular_expression/tests/test_python_regex.py

@@ -199,7 +199,7 @@ def test_shortcut_word(self):
     def _test_compare(self, regex, s_test):
         r_pyformlang = PythonRegex(regex)
         r_python = re.compile(regex)
-        self.assertEqual(r_python.match(s_test) is not None, r_pyformlang.accepts(s_test))
+        self.assertEqual(r_python.fullmatch(s_test) is not None, r_pyformlang.accepts(s_test))
 
     def test_backslash(self):
         self._test_compare(".*", "]")
@@ -283,3 +283,28 @@ def test_dot_harder(self):
         self._test_compare(r"\.", ".")
         self._test_compare(r"\\\.", "\\a")
         self._test_compare(r"\\\.", "\\.")
+
+    def test_single_repetition(self):
+        self._test_compare(r"\d{3}-\d{3}-\d{4}", "012-876-3789")
+        self._test_compare(r"a{5}b", "ab")
+        self._test_compare(r"a{5}b", "aaaaab")
+        self._test_compare(r"a{5b", "aaaaab")
+        self._test_compare(r"a{5b", "a{5b")
+        self._test_compare(r"T{4}P{3}", "TTTTTTPPPPPPPPPPPP")
+
+    def test_range_repetition(self):
+        self._test_compare(r"a{2,5}b", "ab")
+        self._test_compare(r"a{2,5}b", "aab")
+        self._test_compare(r"a{2,5}b", "aaaaab")
+        self._test_compare(r"a{2,5}b", "aaaaaab")
+        self._test_compare(r"a{2,5,7}b", "aaaaab")
+        self._test_compare(r"a{2,5,7}b", "a{2,5,7}b")
+        self._test_compare(r"ab{2,5}", "ab")
+        self._test_compare(r"ab{2,5}", "abbb")
+        self._test_compare(r"ab{2,5}", "abbbbb")
+        self._test_compare(r"ab{2,5}", "abbbbbbbbb")
+        self._test_compare(r"[a-z]{1,3}", "")
+        self._test_compare(r"[a-z]{1,3}", "d")
+        self._test_compare(r"[a-z]{1,3}", "do")
+        self._test_compare(r"[a-z]{1,3}", "dpo")
+        self._test_compare(r"[a-z]{1,3}", "dpoz")