def matchOnlyAtCol(n):
def verifyCol(strg,locn,toks):<EOL><INDENT>if col(locn,strg) != n:<EOL><INDENT>raise ParseException(strg,locn,"<STR_LIT>" % n)<EOL><DEDENT><DEDENT>return verifyCol<EOL>
Helper method for defining parse actions that require matching at a specific
       column in the input text.