Re: Add internal definitions to derived forms

["Ludovic Courtès" <ludo@gnu.org>]

Hello!

Linus Björnstam <linus.bjornstam@veryfast.biz> skribis:

> This commit adds internal definitions to derived conditional forms,
> with-fluids and and-let*. This means the bodies of when, unless and
> with-fluids, and the clause bodies of case and cond behave like a
> lambda body.
>
> There is no performance hit since guile optimizes a (let () ...)
> without internal definitions to a begin (i.e: no new lexical context
> is created).

Daniel pushed this as 764e3614b8c13de604399572a67d071621e9ca21 in
‘main’.  I had completely overlooked this thread but I wasn’t quite sure
about it, so I did not include it in 3.0.9.

The reason I’m hesitant is that, while I think it’s nice to be able to
have local ‘define’ in these contexts, I’m wary of diverging from R5RS
and R6RS.  Since it’s a one-way change (we won’t be able to revert it
once people rely on it), I thought we’d rather be careful.

What do people think?  Andy?

Thanks,
Ludo’.