"""
Multiple Dispatch is *the* feature in Julia that makes it great.
So there's a port to Python as well, but it had to be programmed since it's not in the heart
of Python.

See
https://en.wikipedia.org/wiki/Multiple_dispatch
https://pypi.org/project/multipledispatch/
https://pypi.org/project/multimethod/
"""


from multipledispatch import dispatch
from multimethod import multimethod



# The point of multiple dispatch is to avoid isinstance  
# the same functionality in plain Python

def multiadd(x, y):
    if isinstance(x, int) and isinstance(y, int):
        return x + y
    elif isinstance(x, object) and isinstance(y, object):
        return "%s + %s" % (x, y)
    else:
        raise TypeError("unsupported argument types (%s, %s)" % (type(x), type(y)))


res1 = multiadd(1, 2)
res2 = multiadd(1, 'hello')

print('res1: ',res1)
print('res2: ',res2)


# 1st solution: multipledispatch

@dispatch(int, int)
def add(x, y):
    return x + y

@dispatch(object, object)
def add(x, y):
    return "%s + %s" % (x, y)


res3 = add(1, 2)
res4 = add(1, 'hello')

print('res3: ',res3)
print('res4: ',res4)


# 2nd solution: multimethod
# pros: type hints in function calls, not in the decorator
#       fastest implementation one can have in Python ? 

@multimethod
def add(x :int, y :int):
    return x + y

@multimethod
def add(x :object, y :object):
    return "%s + %s" % (x, y)


res5 = add(1, 2)
res6 = add(1, 'hello')

print('res5: ',res5)
print('res6: ',res6)



"""
If you have just 
def add(x, y):
    return x + y

then
  add(1, 'hello')
gives TypeError: unsupported operand type(s) for +: 'int' and 'str'

"""