#boduch - Simple Python tool library.
#   Copyright (C) 2008  Adam Boduch
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU Affero General Public License as
#   published by the Free Software Foundation, either version 3 of the
#   License, or (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU Affero General Public License for more details.
#
#   You should have received a copy of the GNU Affero General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.

from zope.interface import Interface, Attribute

class IPredicate(Interface):
    lop=Attribute("""The left-hand operator.""")
    rop=Attribute("""The right-hand operator.""")
    result=Attribute("""The result of the comparison""")
    
    def __nonzero__(self):
        """Return the result of the comparison."""
        
    def invoke_operators(self):
        """Check if the operators of this predicate are callable
        and if so, call'em."""
        
__all__=['IPredicate']