#
# This file is part of pySMT.
#
# Copyright 2014 Andrea Micheli and Marco Gario
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
[docs]class Interpolator(object):
def __init__(self):
self._destroyed = False
[docs] def binary_interpolant(self, a, b):
"""Returns a binary interpolant for the pair (a, b), if And(a, b) is
unsatisfaiable, or None if And(a, b) is satisfiable.
"""
raise NotImplementedError
[docs] def sequence_interpolant(self, formulas):
"""Returns a sequence interpolant for the conjunction of formulas, or
None if the problem is satisfiable.
"""
raise NotImplementedError
def __enter__(self):
"""Manage entering a Context (i.e., with statement)"""
return self
def __exit__(self, exc_type, exc_val, exc_tb):
"""Manage exiting from Context (i.e., with statement)
The default behaviour is to explicitely destroy the interpolator to
free the associated resources.
"""
self.exit()
[docs] def exit(self):
"""Destroys the solver and closes associated resources."""
if not self._destroyed:
self._exit()
self._destroyed = True
def _exit(self):
"""Destroys the solver and closes associated resources."""
raise NotImplementedError