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#####################################################
# Decision theory proto
#
# Copyright (c) 2010 Emile Kroeger
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
#####################################################
#####################################################
# Predicates
#####################################################
class _BinaryPredicate:
def __init__(self, predicate1, predicate2):
self.predicate1 = predicate1
self.predicate2 = predicate2
def __str__(self):
return "(%s %s %s)" % (str(self.predicate1), self.symbol,
str(self.predicate2))
class Is:
def __init__(self, varname, value):
self.varname = varname
self.value = value
def fulfills(self, state):
#print "", str(self)
#print " fulfilled by", str(state)
return state[self.varname] == self.value
def __str__(self):
return "(%s == %s)" % (str(self.varname), str(self.value))
class Not:
def __init__(self, predicate):
self.predicate = predicate
def fulfills(self, state):
return not self.predicate.fulfills(state)
def __str__(self):
return "!" + str(self.predicate)
class And(_BinaryPredicate):
symbol = "&"
def fulfills(self, state):
if self.predicate1.fulfills(state):
return self.predicate2.fulfills(state)
class Or(_BinaryPredicate):
symbol = "|"
def fulfills(self, state):
if self.predicate1.fulfills(state):
return True
else:
return self.predicate2.fulfills(state)
class Implies(_BinaryPredicate):
symbol = "->"
def fulfills(self, state):
if self.predicate2.fulfills(state):
return True
else:
return not self.predicate1.fulfills(state)
class Equivalent(_BinaryPredicate):
symbol = "<->"
def fulfills(self, state, context):
if self.predicate2.fulfills(state):
return self.predicate1.fulfills(state)
else:
return not self.predicate1.fulfills(state)