DSL for handle binding

[John Rose]

On Mar 21, 2011, at 3:24 PM, Charles Oliver Nutter wrote:

> I did get reorder in, and it's far easier for me to follow when
> explicitly going forward:
> 
>        MethodHandle handle = Binder
>                .from(String.class, Integer.class, Float.class, String.class)
>                .drop(0, 2)
>                .reorder(0, 0)
>                .invoke(target);
> 
> ...with the end target having a signature of (String, String)String.
> My brain is happy.

The small integers are a little hard to decode since they shift from step to step.  In the above case, I think you don't need the explicit drop:

       MethodHandle handle = Binder
               .from(String.class, Integer.class, Float.class, String.class)
               .reorder(3, 3)
               .invoke(target);

Also, some users (including Ola, I think) have requested a combined transform which (a) drops, (b) permutes, and (c) introduces bound values.  With Binder it would look like one of these:

       MethodHandle handle = Binder
               .from(String.class, Integer.class, Float.class, String.class)
               .reorder(Binder.arg(3), new File("foo"), Binder.arg(3))
               .invoke(target);

which ends with type signature (String, File, String)String.  Or even:

       MethodHandle handle = Binder
               .from(String.class, Integer.class, Float.class, String.class)
               .invoke(target, Binder.arg(3), new File("foo"), Binder.arg(3));

-- John