100 lines
2.1 KiB
Python
100 lines
2.1 KiB
Python
#! /usr/bin/env python
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# -*- coding: utf-8 -*-
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# vim:fenc=utf-8
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#
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# Copyright © 2017 lafrite <lafrite@Poivre>
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#
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# Distributed under terms of the MIT license.
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"""
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Minus MO: take the opposit
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"""
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from ..MO.mo import MO, MOnumber
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from ..MO.fraction import MOFraction
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from .exceptions import MinusError
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def minus(left, right):
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""" Perform the minusition of left and right
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:param left: left MO
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:param right: right MO
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:returns: Tree or MO
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>>> a = MOnumber(4)
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>>> minus(None, a)
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<MOnumber - 4>
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>>> a = MOnumber(-4)
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>>> minus(None, a)
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<MOnumber 4>
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>>> b = MOnumber(0)
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>>> minus(None, b)
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<MOnumber 0>
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"""
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if not left is None:
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raise MinusError(f"'-' is a 1 arity operator, left should be None (got {left})")
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return MINUSFUNCTIONS[type(right)](right)
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def monumber(right):
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""" Minusing monumber
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:param right: right MOnumber
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:returns: MONumber
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>>> a = MOnumber(4)
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>>> monumber(a)
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<MOnumber - 4>
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"""
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return MO.factory(- right.value)
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def mofraction(right):
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""" Minusing a mofraction
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:param right: a mofraction
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:returns: Tree with the number converted into a mofraction
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>>> a = MOFraction(6, 5)
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>>> print(mofraction(a))
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-
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> None
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> /
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| > 6
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| > 5
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>>> a = MOFraction(6, 5, True)
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>>> print(mofraction(a))
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/
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> 6
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> 5
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"""
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if right.negative:
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return MOFraction(right._numerator, right._denominator)
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try:
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if right._numerator < 0:
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return MOFraction(-right._numerator, right._denominator)
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except TypeError:
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pass
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try:
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if right._denominator < 0:
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return MOFraction(right._numerator, -right._denominator)
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except TypeError:
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pass
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return MOFraction(right._numerator, right._denominator, True)
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# TODO: Faire un décorateur pour un enregistrement automatique |dim. mars 11 18:24:32 EAT 2018
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MINUSFUNCTIONS = {
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MOnumber: monumber,
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MOFraction: mofraction,
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}
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# -----------------------------
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# Reglages pour 'vim'
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# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
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# cursor: 16 del
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