Mapytex/mapytex/calculus/core/compute/divide.py

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

"""
Divide MO
"""

from ..tree import Tree
from ..MO.mo import MO, MOnumber
from ..MO.fraction import MOFraction
from .exceptions import DivideError


def divide(left, right):
    """ Perform the addition of left and right

    :param left: left MO
    :param right: right MO
    :returns: Tree or MO

    >>> a = MOnumber(4)
    >>> b = MOnumber(6)
    >>> divide(a, b)
    <MOFraction 4 / 6>
    >>> b = MOnumber(0)
    >>> divide(a, b)
    Traceback (most recent call last):
        ...
    mapytex.calculus.core.compute.exceptions.DivideError: Division by zero

    """
    try:
        right.value
    except AttributeError:
        pass
    else:
        if right.value == 0:
            raise DivideError("Division by zero")

    if right.value == 1:
        return left

    return MULFUNCTIONS[(type(left), type(right))](left, right)

def monumber_monumber(left, right):
    """ Divide 2 monumbers

    :param left: left MOnumber
    :param right: right MOnumber
    :returns: MONumber

    >>> a = MOnumber(4)
    >>> b = MOnumber(6)
    >>> monumber_monumber(a, b)
    <MOFraction 4 / 6>
    """
    return MOFraction(left, right)

def monumber_mofraction(left, right):
    """ Divide a monumber and a mofraction

    :param left: a monumber
    :param right: a mofraction
    :returns: Tree with the multiplication on the numerator

    >>> a = MOnumber(4)
    >>> b = MOFraction(6, 5)
    >>> print(monumber_mofraction(a, b))
    *
     > 4
     > /
     | > 5
     | > 6
    >>> b = MOFraction(6, 5, True)
    >>> print(monumber_mofraction(a, b))
    *
     > 4
     > -
     | > None
     | > /
     | | > 5
     | | > 6
    """
    if not isinstance(left, MOnumber) or not isinstance(right, MOFraction):
        raise DivideError(f"Wrong type for left (got {left.__class__.__name__}) \
                or right (got {right.__class__.__name__})")

    return Tree("*", left, right.inverse())

def mofraction_monumber(left, right):
    """ Divide a monumber and a mofraction

    :param left: a mofraction
    :param right: a monumber
    :returns: Tree with a new calculus

    >>> a = MOFraction(6, 5)
    >>> b = MOnumber(4)
    >>> print(mofraction_monumber(a, b))
    *
     > /
     | > 6
     | > 5
     > /
     | > 1
     | > 4
    """

    if not isinstance(left, MOFraction) or not isinstance(right, MOnumber):
        raise DivideError(f"Wrong type for left (got {left.__class__.__name__})"
                          f"or right (got {right.__class__.__name__})")

    right_fraction = MOFraction(1, right)
    return Tree("*", left, right_fraction)

def mofraction_mofraction(left, right):
    """ Divide two mofractions

    :param left: a mofraction
    :param right: a mofraction
    :returns: Tree with a new calculus

    >>> a = MOFraction(1, 5)
    >>> b = MOFraction(4, 5)
    >>> print(mofraction_mofraction(a, b))
    *
     > /
     | > 1
     | > 5
     > /
     | > 5
     | > 4

    """

    if not isinstance(left, MOFraction) or not isinstance(right, MOFraction):
        raise AddError(f"Wrong type for left (got {left.__class__.__name__})"
                f"or right (got {right.__class__.__name__})")

    return Tree("*", left, right.inverse())

# TODO: Faire un décorateur pour un enregistrement automatique |dim. mars 11 18:24:32 EAT 2018
MULFUNCTIONS = {
    (MOnumber, MOnumber): monumber_monumber,
    (MOnumber, MOFraction): monumber_mofraction,
    (MOFraction, MOnumber): mofraction_monumber,
    (MOFraction, MOFraction): mofraction_mofraction,
    }

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