Jens Axel S?gaard wrote:
> I think it is due to libraries. Since "By default, all of an imported
> library?s exported bindings are made visible within an importing library
> using the names given to the bindings by the imported library", it
> should be possible to check whether there is a conflict betweeen
> imported names and names defined in the library. Postponing the
> expansion of the RHS allows the expander to determine all names in the
> global scope before expansion of the right hand sides begin.
I don't see how that helps any, if the imported library can
export macros that are used using the expansion of the
importing library/program:
(import ....)
(MAC ...) ; MAC imported from the library
(define VAR ...)
MAC needs to be expanded immediately, not deferred.
You can check for the conflict when you see the define,
regardless of whether you defer expanding the RHS.
> It also simplifies the expansion of internal definitions.
Perhaps, though you haven't shown how. But our goal isn't to
"simplify expansion", it is to specify a coherent and useful
language.
Kawa defers lambdas, rather than RHSs. (Though Kawa doesn't
defer expanding lambdas until call-time, like I suggested
would be useful for repl/load.)
--
--Per Bothner
per_at_bothner.com http://per.bothner.com/
Received on Thu Feb 22 2007 - 16:27:05 UTC