def matchOnlyAtCol(n):
    """
    Helper method for defining parse actions that require matching at a specific
    column in the input text.
    """
    def verifyCol(strg,locn,toks):
        if col(locn,strg) != n:
            raise ParseException(strg,locn,"matched token not at column %d" % n)
    return verifyCol

    Helper method for defining parse actions that require matching at a specific
    column in the input text.
    
src/pkg_resources/_vendor/pyparsing.py