optional arguments handlers

[Jim Blandy <jimb@red-bean.com>]

>With all this discussion on optional arguments handlers, has anyone
>looked at the let-optionals macros used in scsh (let-opt.scm)?
>
>They're implemented in Clinger/Rees high level macros and handle
>optional arguments in a very schemely manner. Here's some of the doc
>from that file.

I like the macro, too; It might be a good idea to copy these into the
stock Guile environment.

In the long run, I think we'll see some interpreter-level support for
keyword and optional arguments.  But it's not towards the top of the
list.