[myhdl-list] [newb] modelling question

[Neal B. <ndb...@gm...>]

Simple question.  Model an accumulator.  The accumulator has state (call it
'sum').

Most examples are an RTL style.  My imitation of this style might be: 

def accum (x, result, _sum, count, clock, n):
    @always (clock.posedge)
    def accum_logic(x):
        _sum.next += x
        if count == n-1:
            result.next = _sum
            _sum.next = 0

    return accum_logic

_sum is an internal variable.  Does it need to be one of the parameters passed
to accum, as I showed above?

Perhaps this could be:
def accum (x, result, count, clock, n):

    _sum = Signal (0)

    @always (clock.posedge)
    def accum_logic(x):
        _sum.next += x
        if count == n-1:
            result.next = _sum
            _sum.next = 0

    return accum_logic

What if I prefer object oriented style?  The manual mentions this (the fifo
examples).  I wonder if this style will work properly with the rest of myhdl? 
For example, there are some functions that 'infer' inputs and outputs.  Does
this work if I use this object-oriented style?  There must be some constraints.