Render momonial and multiply with scalar

mapytex/calculus/core/compute/multiply.py

@@ -11,8 +11,9 @@ Multiply MO
 """
 
 from ..tree import Tree
-from ..MO.mo import MO, MOnumber
+from ..MO.mo import MO, MOnumber, MOstr
 from ..MO.fraction import MOFraction
+from ..MO.monomial import MOMonomial
 from .exceptions import MultiplyError
 from .type_filter import args_are
 
@@ -145,6 +146,46 @@ def mofraction_mofraction(left, right):
     denom = Tree("*", left.denominator, right.denominator)
     return Tree("/", num, denom)
 
+@args_are((MOnumber, MOFraction), MOstr)
+def moscalar_mostr(left, right):
+    """ Multiply a scalar with a letter
+
+    >>> a = MOnumber(2)
+    >>> b = MOstr('x')
+    >>> moscalar_mostr(a, b)
+    <MOMonomial 2x>
+    >>> a = MOFraction(1, 5)
+    >>> moscalar_mostr(a, b)
+    <MOMonomial 1 / 5x>
+    """
+    return MOMonomial(left, right)
+
+@args_are(MOstr, (MOnumber, MOFraction))
+def mostr_moscalar(left, right):
+    """ Multiply a scalar with a letter
+
+    >>> a = MOstr('x')
+    >>> b = MOnumber(2)
+    >>> mostr_moscalar(a, b)
+    <MOMonomial 2x>
+    >>> b = MOFraction(1, 5)
+    >>> mostr_moscalar(a, b)
+    <MOMonomial 1 / 5x>
+    """
+    return MOMonomial(right, left)
+
+@args_are((MOnumber, MOFraction), MOMonomial)
+def moscalar_monomonial(left, right):
+    """ Multiply a scalar with a monomial
+
+    >>> a = MOnumber(4)
+    >>> b = MOMonomial(5, 'x', 3)
+
+    # >>> print(moscalar_monomonial(a, b))
+    """
+    coefficient = Tree('*', left, right._coefficient)
+    return Tree('*', coefficient, MOMonomial(1, right._variable, right._power))
+
 # TODO: Faire un décorateur pour un enregistrement automatique |dim. mars 11 18:24:32 EAT 2018
 MULFUNCTIONS = {
     (MOnumber, MOnumber): monumber_monumber,