#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright © 2017 lafrite <lafrite@Poivre>
#
# Distributed under terms of the MIT license.

__all__ = ["OperatorError", "OPERATORS", "is_operator"]

class OperatorError(Exception):
    pass

OPERATORS = {
    "+": {'repr': "+",
          'arity': 2,
          'precedence': 0,
         },
    "-": {'repr': "-",
          'arity': 1,
          'precedence': 1,
         },
    "*": {'repr': "*",
          'arity': 2,
          'precedence': 2,
         },
    "/": {'repr': "/",
          'arity': 2,
          'precedence': 3,
         },
    "^": {'repr': "^",
          'arity': 2,
          'precedence': 4,
         },
}

def is_operator(string):
    """ Return whether a string is an operator or not

    :param string: string to test
    :returns: boolean

    :example:

    >>> is_operator("+")
    True
    >>> is_operator("i")
    False

    """
    return string in OPERATORS.keys()


# -----------------------------
# Reglages pour 'vim'
# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
# cursor: 16 del