Bugfix in completer: don't hang when pasting a long string with many backslashes.

Author: jonathanslenders

ptpython/completer.py

@@ -62,9 +62,9 @@ def double_quoted_wrapper(text):
         grammar = r"""
                 # Text before the current string.
                 (
-                    [^'"#]                             |  # Not quoted characters.
-                    '''  ([^']|'[^']|''[^']|\\.)*  ''' |  # Inside single quoted triple strings
-                    "" " ([^"]|"[^"]|""[^"]|\\.)* "" " |  # Inside double quoted triple strings
+                    [^'"#]                                  |  # Not quoted characters.
+                    '''  ([^'\\]|'(?!')|''(?!')|\\.])*  ''' |  # Inside single quoted triple strings
+                    "" " ([^"\\]|"(?!")|""(?!^)|\\.])* "" " |  # Inside double quoted triple strings
 
                     \#[^\n]*(\n|$)           |  # Comment.
                     "(?!"") ([^"\\]|\\.)*"   |  # Inside double quoted strings.