streaming redux

[Sean Kelly]

Michel Fortin Wrote:
> 
> So because of all this virtual dispatch and all this rigidity, I think 
> Formatter needs to be rethought a little. My preference obviously goes 
> to satically-typed formatters. But what I'd like to see is something 
> like this:
> 
> 	interface Serializable(F) {
> 		void writeTo(F formatter);
> 	}
> 
> Any object can implement a serialization for a given formatter by 
> implementing the interface above parametrized with the formatter type.

I like it.  There needs to be some way to hold format-specific state info for a stream though.  I guess this could be done via an external hash (stream address to formatter state), but it would be nicer if this could be stored in the stream itself somehow.