# coding=utf-8
# Copyright 2018 The Tensor2Tensor Authors.
#
# 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.

"""Algorithmic data generators for symbolic math tasks.

"""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

from collections import namedtuple
import random
import six
from six.moves import range  # pylint: disable=redefined-builtin
import sympy


class ExprOp(object):
  """Represents an algebraic operation, such as '+', '-', etc."""

  def __init__(self, symbol, precedence, associative=False):
    """Constructor.

    Args:
      symbol: The character which represents this operation, such as '+' for
          addition.
      precedence: Operator precedence. This will determine where parentheses
          are used.
      associative: If true, the order of the operands does not matter.
    """
    self.symbol = symbol
    self.precedence = precedence