Fixed Python grammars

examples/python2.g

@@ -152,9 +152,8 @@ _NEWLINE: ( /\r?\n[\t ]*/ | COMMENT )+
 %ignore /\\[\t \f]*\r?\n/   // LINE_CONT 
 %ignore COMMENT
 
-
-STRING : /[ub]?r?("(?!"").*?(?<!\\\\)(\\\\\\\\)*?"|'(?!'').*?(?<!\\\\)(\\\\\\\\)*?')/i
-LONG_STRING.2: /[ub]?r?(""".*?(?<!\\\\)(\\\\\\\\)*?"""|'''.*?(?<!\\\\)(\\\\\\\\)*?''')/is
+STRING : /[ubf]?r?("(?!"").*?(?<!\\)(\\\\)*?"|'(?!'').*?(?<!\\)(\\\\)*?')/i
+LONG_STRING.2: /[ubf]?r?(""".*?(?<!\\)(\\\\)*?"""|'''.*?(?<!\\)(\\\\)*?''')/is
 
 DEC_NUMBER: /[1-9]\d*l?/i
 HEX_NUMBER: /0x[\da-f]*l?/i

examples/python3.g

@@ -173,12 +173,8 @@ _NEWLINE: ( /\r?\n[\t ]*/ | COMMENT )+
 %ignore /\\[\t \f]*\r?\n/   // LINE_CONT
 %ignore COMMENT
 
-
-
-// STRING : /[ub]?r?("(?!"").*?(?<!\\)(\\\\)*?"|'(?!'').*?(?<!\\)(\\\\)*?')/
-// LONG_STRING: /(?s)[ub]?r?(""".*?(?<!\\)(\\\\)*?"""|'''.*?(?<!\\)(\\\\)*?''')/
-STRING : /[ubf]?r?("(?!"").*?(?<!\\\\)(\\\\\\\\)*?"|'(?!'').*?(?<!\\\\)(\\\\\\\\)*?')/i
-LONG_STRING: /[ubf]?r?(""".*?(?<!\\\\)(\\\\\\\\)*?"""|'''.*?(?<!\\\\)(\\\\\\\\)*?''')/is
+STRING : /[ubf]?r?("(?!"").*?(?<!\\)(\\\\)*?"|'(?!'').*?(?<!\\)(\\\\)*?')/i
+LONG_STRING: /[ubf]?r?(""".*?(?<!\\)(\\\\)*?"""|'''.*?(?<!\\)(\\\\)*?''')/is
 
 DEC_NUMBER: /[1-9]\d*l?/i
 HEX_NUMBER: /0x[\da-f]*l?/i

lark/load_grammar.py

@@ -293,7 +293,7 @@ def _rfind(s, choices):
 
 
 def _fix_escaping(s):
-    s = s.replace('\\"', '"')
+    s = s.replace('\\"', '"').replace("'", "\\'")
     w = ''
     i = iter(s)
     for n in i: