Ability to change PEP8 flags on the fly in source file via inline comments

pep8.py

@@ -1205,6 +1205,23 @@ def readline_check_physical(self):
         used to feed tokenize.generate_tokens.
         """
         line = self.readline()
+
+        def parse_inline_flags(sign):
+            """
+            Parse inline flags in source file.
+
+            Flags are specified as follows:
+
+            #:PEP8 +E101 -W603
+            """
+            return set(map(lambda s: s[1:].strip(),
+                           filter(lambda s: s.startswith(sign),
+                                  line.split(" ")[1:])))
+
+        if line.lstrip().startswith('#:PEP8'):
+            self.report.expected = \
+                (self.report.expected | parse_inline_flags('-')) \
+                - parse_inline_flags('+')
         if line:
             self.check_physical(line)
         return line
@@ -1313,6 +1330,7 @@ def check_all(self, expected=None, line_offset=0):
         """
         Run all checks on the input file.
         """
+        self.line_offset = line_offset
         self.report.init_file(self.filename, self.lines, expected, line_offset)
         self.line_number = 0
         self.indent_char = None
@@ -1383,7 +1401,7 @@ def init_file(self, filename, lines, expected, line_offset):
         """Signal a new file."""
         self.filename = filename
         self.lines = lines
-        self.expected = expected or ()
+        self.expected = set(expected or ())
         self.line_offset = line_offset
         self.file_errors = 0
         self.counters['files'] += 1