# -*- coding: utf-8 -*-
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# Copyright (c) 2002-2010 Nexedi SA and Contributors. All Rights Reserved.
#                    Jean-Paul Smets-Solanes <jp@nexedi.com>
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"""
Products.ERP5.interfaces.predicate
"""

from zope.interface import Interface

class IPredicate(Interface):
  """Predicate document interface specification

  A Predicate allows to make a statement about a document.
  A statement can be related to:

  - the attributes of the document (ex. price >= 3.0)

  - the categories of the document (ex. )

  The Predicate class is an abstract class, which is
  implemented by subclasses.
  """

  def test(context, tested_base_category_list=None):
    """
    A Predicate can be tested on a given context. Parameters can
    passed in order to ignore some conditions:
    
    tested_base_category_list -- a list of category that we do
        want to test. For example, we might want to test only the
        destination or the source of a predicate.
        (XXX-JPS - is this really needed ? is this appropriate
         naming - probably not)
    """

  def asSQLExpression():
    """
    A Predicate can be rendered as an sql expression. This
    can be useful to create reporting trees based on the
    ZSQLCatalog. This SQL expression is however partial since
    python scripts which are used by the test method of the predicate
    can be converted to SQL. If a python script is defined to 
    implement test, results obtained through asSQLExpression
    must be additionnaly tested by invoking test().
    """