[erlang-questions] Cannot get the hang of single assignment

Dustin Sallings <>
Fri Aug 17 22:04:15 CEST 2007


On Aug 17, 2007, at 12:35 , Tom Ayerst wrote:

> I think I am missing something obvious here.  I was reading Jim  
> Menard's
> account of writing a boids flocking simulator and wanted to have a go.
> Giving each Boid its own process was obvious but, I am very new to
> erlang and was then stumped.
>
> How should I track the state (position and vector) of each Boid?

	The general way you do this in a functional language is by passing  
the parameters in to a tail-recursive function.

	I have no idea what a Boid is, but it seems to have a position and a  
vector, and I'm assuming does something to change these.  I imagine  
your process's main loop would look something like this:

loop(Position, Vector) ->
     {NewPosition, NewVector} = compute_new_position_and_vector 
(Position, Vector),
     loop(NewPosition, NewVector).

-- 
Dustin Sallings





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