From 859854079ca2b9dc3f80e045280faa11013cbd3b Mon Sep 17 00:00:00 2001
From: Jeroen van der Heijden <jeroen@cesbit.com>
Date: Sat, 23 Jul 2022 18:26:57 +0200
Subject: [PATCH] Optional line numbers in expecting and allow flags in front
 of regex

---
 pyleri/__init__.py |  2 +-
 pyleri/regex.py    | 19 ++++++++++++++++++-
 pyleri/result.py   | 10 ++++++++--
 test/test_list.py  | 12 ++++++++++++
 test/test_regex.py |  9 +++++++++
 5 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/pyleri/__init__.py b/pyleri/__init__.py
index 08f0631..d2e8858 100644
--- a/pyleri/__init__.py
+++ b/pyleri/__init__.py
@@ -41,4 +41,4 @@
 __author__ = 'Jeroen van der Heijden'
 __maintainer__ = 'Jeroen van der Heijden'
 __email__ = 'jeroen@cesbit.com'
-__version__ = '1.3.4'
+__version__ = '1.4.0'
diff --git a/pyleri/regex.py b/pyleri/regex.py
index 3020483..9636b65 100644
--- a/pyleri/regex.py
+++ b/pyleri/regex.py
@@ -5,6 +5,18 @@
 import re
 from .elements import NamedElement, c_export, go_export, java_export
 
+_RE_FLAGS = re.compile(
+    r'^('
+    r'(\(\?i\))|'
+    r'(\(\?m\))|'
+    r'(\(\?s\))|'
+    r'(\(\?A\))|'
+    r'(\(\?x\))|'
+    r'(\(\?X\))|'
+    r'(\(\?U\))|'
+    r'(\(\?:\))'
+    r')(.)')
+
 
 class Regex(NamedElement):
 
@@ -12,7 +24,12 @@ class Regex(NamedElement):
 
     def __init__(self, pattern, flags=0):
         if not pattern.startswith('^'):
-            pattern = '^' + pattern
+            m = _RE_FLAGS.match(pattern)
+            if not m:
+                pattern = '^' + pattern
+            elif m.group(2) != '^':
+                pos = m.end() - 1
+                pattern = pattern[:pos] + '^' + pattern[pos:]
         assert flags == 0 or flags == re.IGNORECASE, \
             'Only re.IGNORECASE is currently accepted as flag'
         self._compiled = re.compile(pattern, flags=flags)
diff --git a/pyleri/result.py b/pyleri/result.py
index bc4e765..d080e8f 100644
--- a/pyleri/result.py
+++ b/pyleri/result.py
@@ -21,10 +21,16 @@ def __init__(self, is_valid, pos):
         self.expecting = None
         self.tree = None
 
-    def as_str(self, translate=None):
+    def as_str(self, translate=None, line_number=False):
         if self.is_valid:
             return 'parsed successfully'
-        res = ['error at position {}'.format(self.pos)]
+        if line_number:
+            string = self.tree._string
+            lnr = string.count('\n', 0, self.pos) + 1
+            pos = self.pos - string.rfind('\n', 0, self.pos)
+            res = ['error at line {}, col {}'.format(lnr, pos)]
+        else:
+            res = ['error at position {}'.format(self.pos)]
         arr = []
         for elem in (self.expecting):
             expectstr = translate(elem) if translate else None
diff --git a/test/test_list.py b/test/test_list.py
index 5e83eef..d91cdf6 100644
--- a/test/test_list.py
+++ b/test/test_list.py
@@ -63,6 +63,18 @@ def test_list_all_options(self):
             'error at position 0, expecting: hi'
         )
 
+        self.assertEqual(
+            grammar.parse('').as_str(line_number=True),
+            'error at line 1, col 1, expecting: hi'
+        )
+
+        self.assertEqual(
+            grammar.parse("""
+                hi-hi-hi-hi-hi
+            """).as_str(line_number=True),
+            'error at line 2, col 26, expecting: end_of_statement'
+        )
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/test/test_regex.py b/test/test_regex.py
index 6ec0c2c..da622ac 100644
--- a/test/test_regex.py
+++ b/test/test_regex.py
@@ -28,6 +28,15 @@ def test_regex(self):
                 if elem is regex else None),
             'error at position 0, expecting: single_quoted_string'
         )
+        self.assertTrue(grammar.parse("'hi'").is_valid)
+
+    def test_flags_regex(self):
+        regex = Regex(r'(?s)//.*?(\r?\n|$)')
+        grammar = create_grammar(regex)
+
+        self.assertTrue(grammar.parse("""
+                //test
+        """).is_valid)
 
 
 if __name__ == '__main__':