third_party.pylibs.pylint.src/examples/custom_raw.py

from pylint.interfaces import IRawChecker
from pylint.checkers import BaseChecker

class MyRawChecker(BaseChecker):
    """check for line continuations with '\' instead of using triple
    quoted string or parenthesis
    """

    __implements__ = IRawChecker

    name = 'custom_raw'
    msgs = {'W9901': ('use \\ for line continuation',
                      ('Used when a \\ is used for a line continuation instead'
                       ' of using triple quoted string or parenthesis.')),
            }
    options = ()

    def process_module(self, node):
        """process a module

        the module's content is accessible via node.stream() function
        """
        with module.stream() as stream:
            for (lineno, line) in enumerate(stream):
                if line.rstrip().endswith('\\'):
                    self.add_message('W9901', line=lineno)


def register(linter):
    """required method to auto register this checker"""
    linter.register_checker(MyRawChecker(linter))