From b51ac7880d1274182106090d88f888fc3e82b0bd Mon Sep 17 00:00:00 2001
From: Bertrand Benjamin <benjamin.bertrand@opytex.org>
Date: Mon, 15 Jul 2019 10:42:13 +0200
Subject: [PATCH] Fix: typing filter for multiply

---
 mapytex/calculus/core/typing/multiply.py | 29 +++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/mapytex/calculus/core/typing/multiply.py b/mapytex/calculus/core/typing/multiply.py
index 24f356a..9042f77 100644
--- a/mapytex/calculus/core/typing/multiply.py
+++ b/mapytex/calculus/core/typing/multiply.py
@@ -15,6 +15,7 @@ from ..tree import Tree
 from ..MO import MO, MOnumber, MOstr
 from ..MO.fraction import MOFraction
 from ..MO.monomial import MOstrPower, MOMonomial
+from ..compute.filters import special_case
 
 multiply_doc = """ Multiply MOs
 
@@ -26,8 +27,26 @@ multiply_doc = """ Multiply MOs
 
 multiply = Dispatcher("multiply", doc=multiply_doc)
 
+def multiply_filter(left, right):
+    """ Automatic multiply on MO
+
+    :param left: MO
+    :param right: MO
+    :returns: MO if it is a special case, nothing other wise
+    """
+    try:
+        if left == 1:
+            return right
+    except TypeError:
+        pass
+    try:
+        if right == 1:
+            return left
+    except TypeError:
+        pass
 
 @multiply.register((MOnumber, MOFraction), MOstr)
+@special_case(multiply_filter)
 def moscalar_mostr(left, right):
     """ Multiply a scalar with a letter to create a MOMonomial
 
@@ -43,6 +62,7 @@ def moscalar_mostr(left, right):
 
 
 @multiply.register(MOstr, (MOnumber, MOFraction))
+@special_case(multiply_filter)
 def mostr_moscalar(left, right):
     """ Multiply a scalar with a letter to create a MOMonomial
 
@@ -58,6 +78,7 @@ def mostr_moscalar(left, right):
 
 
 @multiply.register((MOnumber, MOFraction), MOstrPower)
+@special_case(multiply_filter)
 def moscalar_mostrpower(left, right):
     """ Multiply a scalar with a MOstrPower
 
@@ -65,12 +86,18 @@ def moscalar_mostrpower(left, right):
     >>> x = MOstrPower('x', 4)
     >>> multiply(a, x)
     <MOMonomial 4x^4>
-
+    >>> a = MOnumber(1)
+    >>> x = MOstrPower('x', 4)
+    >>> multiply(a, x)
+    <MOstrPower x^4>
     """
+    #if left == 1:
+    #    return right
     return MOMonomial(left, right)
 
 
 @multiply.register(MOstrPower, (MOnumber, MOFraction))
+@special_case(multiply_filter)
 def mostrpower_moscalar(left, right):
     """ Multiply a MOstrPower with a scalar