streaming redux

[Andrei Alexandrescu]

On 12/28/10 12:07 PM, Sean Kelly wrote:
> 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.

This design prevents new formatters from working with existing class 
hierarchies, unless they themselves obey a hierarchy which undoes the 
very advantage of the design.

It also forces the person defining a class hierarchy to statically 
commit to a specific formatter for the entire hierarchy.

As a corollary this design forces the designer of a hierarchy to make 
early and big decisions.


Andrei