Re: <input> for <pipeline> (action A-87-01)

> I think the consequences of this proposal are:
> 
> 1. A top-level p:pipeline can provide defaults for all of its inputs,
> be they primary or not.
> 
> 2. A p:declare-step or a p:pipeline in a library can define defaults
> for all of its inputs, be they primary or not, but defining a default
> for a primary input is a no-op. It's never used since the the step,
> when it's called, will always bind the primary input port to the
> default readable port (or cause a static error).

1a. A default on a primary input of a top-level p:pipeline will never
be used when the pipeline is called recursively, for the same reason
as (2).

-- Richard