partial_by_order.py

class partial_by_order(object):
    """

    >>> f = partial_by_order(add, [(1, 10)])
    >>> f(5)
    15
    """
    def __init__(self, op, other):
        if (not isinstance(other, list) or
            not all(isinstance(o, tuple) and len(o) == 2 for o in other)):
            raise ValueError('input must be list of tuples')
        self.op = op
        self.other = other

    def __call__(self, *args):
        args2 = list(args)
        for i, arg in self.other:
            args2.insert(i, arg)
        return self.op(*args2)

    @property
    def __name__(self):
        if len(self.other) == 1:
            other_arg = self.other[0][1]
        else:
            other_arg = '...'
        return '{0}({1})'.format(self.op.__name__, other_arg)