From 9610ee1c7e1bc9e63e191551759babc86f5b4ed8 Mon Sep 17 00:00:00 2001
From: Bertrand Benjamin <benjamin.bertrand@opytex.org>
Date: Sat, 17 Mar 2018 10:04:53 +0300
Subject: [PATCH] Use multipledispatcher to define add for MO

---
 mapytex/calculus/core/compute/add.py | 78 +++++++++-------------------
 1 file changed, 24 insertions(+), 54 deletions(-)

diff --git a/mapytex/calculus/core/compute/add.py b/mapytex/calculus/core/compute/add.py
index 3e4846e..619ef09 100644
--- a/mapytex/calculus/core/compute/add.py
+++ b/mapytex/calculus/core/compute/add.py
@@ -16,58 +16,36 @@ from ..MO.fraction import MOFraction
 from .exceptions import AddError
 from .arithmetic import lcm
 from .type_filter import args_are
+from multipledispatch import Dispatcher
 
-
-def add(left, right):
-    """ Perform the addition of left and right
+add_doc = """ Adding MOs
 
     :param left: left MO
     :param right: right MO
-    :returns: Tree or MO
+    :return: Tree or MO
 
-    >>> a = MOnumber(4)
-    >>> b = MOnumber(6)
-    >>> add(a, b)
-    <MOnumber 10>
-    >>> b = MOnumber(0)
-    >>> add(a, b)
-    <MOnumber 4>
+"""
+add = Dispatcher("add", doc=add_doc)
 
-    """
-    if left.value == 0:
-        return right
-    elif right.value ==  0:
-        return left
-
-    return ADDFUNCTIONS[(type(left), type(right))](left, right)
-
-@args_are(MOnumber, MOnumber)
+@add.register(MOnumber, MOnumber)
 def monumber_monumber(left, right):
-    """ Adding 2 monumbers
-
-    :param left: left MOnumber
-    :param right: right MOnumber
-    :returns: MONumber
+    """ Simply add MO value
 
     >>> a = MOnumber(4)
     >>> b = MOnumber(6)
-    >>> monumber_monumber(a, b)
+    >>> add(a, b)
     <MOnumber 10>
 
     """
     return MO.factory(left.value + right.value)
 
-@args_are(MOnumber, MOFraction)
+@add.register(MOnumber, MOFraction)
 def monumber_mofraction(left, right):
-    """ Adding a monumber and a mofraction
-
-    :param left: a monumber
-    :param right: a mofraction
-    :returns: Tree with the number converted into a mofraction
+    """ Return a tree with the MOnumber transformed into a MOFraction
 
     >>> a = MOnumber(4)
     >>> b = MOFraction(6, 5)
-    >>> print(monumber_mofraction(a, b))
+    >>> print(add(a, b))
     +
      > /
      | > 4
@@ -79,17 +57,13 @@ def monumber_mofraction(left, right):
     left_fraction = MOFraction(left, MOnumber(1))
     return Tree("+", left_fraction, right)
 
-@args_are(MOFraction, MOnumber)
+@add.register(MOFraction, MOnumber)
 def mofraction_monumber(left, right):
-    """ Adding a monumber and a mofraction
-
-    :param left: a mofraction
-    :param right: a monumber
-    :returns: Tree with the number converted into a mofraction
+    """ Return a tree with the MOnumber transformed into a MOFraction
 
     >>> a = MOFraction(6, 5)
     >>> b = MOnumber(4)
-    >>> print(mofraction_monumber(a, b))
+    >>> print(add(a, b))
     +
      > /
      | > 6
@@ -101,17 +75,15 @@ def mofraction_monumber(left, right):
     right_fraction = MOFraction(right, MOnumber(1))
     return Tree("+", left, right_fraction)
 
-@args_are(MOFraction, MOFraction)
+@add.register(MOFraction, MOFraction)
 def mofraction_mofraction(left, right):
-    """ Adding two mofractions
+    """ 3 differents cases:
 
-    :param left: a mofraction
-    :param right: a mofraction
-    :returns: Tree 
+    Fractions have same denomintor -> add numerator Tree
 
     >>> a = MOFraction(1, 5)
     >>> b = MOFraction(4, 5)
-    >>> print(mofraction_mofraction(a, b))
+    >>> print(add(a, b))
     /
      > +
      | > 1
@@ -137,6 +109,9 @@ def mofraction_mofraction(left, right):
      | | > None
      | | > 4
      > 5
+
+    A denominator is a multiple of the other
+
     >>> a = MOFraction(1, 2)
     >>> b = MOFraction(1, 4)
     >>> print(mofraction_mofraction(a, b))
@@ -151,6 +126,9 @@ def mofraction_mofraction(left, right):
      > /
      | > 1
      | > 4
+
+    Denominators are coprime
+
     >>> a = MOFraction(1, 2)
     >>> b = MOFraction(1, 5)
     >>> print(mofraction_mofraction(a, b))
@@ -194,14 +172,6 @@ def mofraction_mofraction(left, right):
 
     return Tree("+", left_frac, right_frac)
 
-# TODO: Faire un décorateur pour un enregistrement automatique |dim. mars 11 18:24:32 EAT 2018
-ADDFUNCTIONS = {
-    (MOnumber, MOnumber): monumber_monumber,
-    (MOnumber, MOFraction): monumber_mofraction,
-    (MOFraction, MOnumber): mofraction_monumber,
-    (MOFraction, MOFraction): mofraction_mofraction,
-    }
-
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