On Mon, 13 Feb 2006 eastcoastcoder / gmail.com wrote:

> Anyone know of any generic implementation of a pipeline in ruby?  That
> is, one which takes a bunch of GoF Command objects, and strings them
> together in the classical pipeline configuration.
>
> Any advice on that?
>
> I have a process with a lot of sequential processing, and think that a
> pipeline of Command objects (not just Proc's) might be the way to do
> it.
>
> The downsides of pipelines:
> 1) You can't do selections (if) or sequences (loops).  If you can
> handle this, though, this becomes a virtue, as it keeps everything
> crystal clear and simple.  Witness the ever useful Unix command line
> pipelines.
>
> 2) They don't encapsulate very well, as each stage totally overwrites
> the previous ones.  I'm not sure if I should just accept this, or try
> to use some modification (append only pipeline, etc.).
>
> Any experience or ideas on this appreciated.

this handles any dag.  i wrote it a long time ago

   http://codeforpeople.com/lib/ruby/flow/flow-2.0.0/

hth.

-a

-- 
happiness is not something ready-made.  it comes from your own actions.
- h.h. the 14th dali lama