Re: [PATCH] export/rename

[felix . winkelmann]

> Maybe this already works with the current patch, but can we support:
> 
>     (export (rename foo bar))
> 
> As well as the version with the colon (suffix keyword notation) on the end of 
> export?
> Seems like that would be best for symmetry with the import form.
> 
> (Sorry, it’s just aesthetics, I know.)

Well, aesthetics is important. There are a couple of points, though:

- import "rename" has a different syntax, as it combines an import spec with
  a rename list, here we effectively have a special case (3 argument list).

- exports go through ##sys#validate-exports, so originally "export",
  "define-interface" and the export spec of the "module" form supported the
  same export notation, but now we have a special case for export,
  since we try to shoehorn renaming into the existing "export", but renaming is 
  not allowed in "module" and "define-interface". The "(rename OLD NEW)"
  would be ambiguous with the old interpretation, of course.

- having "rename" + "rename:" adds another special case where both keyword
  and normal symbol is allowed, I don't think we have this anywhere else.

- My original intention was to provide a low-impact renaming export in
  the core in anticipation of re-using it for R7RS support. It still seems
  useful for CHICKEN 5, but since rename-on-export appears to me a
  seldom used feature I thought a separate form is sufficient.


felix