Re: [Scheme-reports] ANN: first draft of R7RS small language available Vitaly Magerya (29 Apr 2011 13:30 UTC)
[Scheme-reports] DELAY AND FORCE Andre van Tonder (23 Apr 2011 22:20 UTC)
[Scheme-reports] Regions of imports unspecified Andre van Tonder (23 Apr 2011 22:31 UTC)
Re: [Scheme-reports] Regions of imports unspecified John Cowan (23 Apr 2011 22:43 UTC)
Re: [Scheme-reports] Regions of imports unspecified Alex Shinn (24 Apr 2011 01:59 UTC)
[Scheme-reports] What are regions of toplevel imports? Andre van Tonder (23 Apr 2011 23:41 UTC)
[Scheme-reports] Internal syntax definition order problem Andre van Tonder (23 Apr 2011 22:39 UTC)
[Scheme-reports] Mutable exports Andre van Tonder (23 Apr 2011 22:48 UTC)
Re: [Scheme-reports] Mutable exports Alex Shinn (24 Apr 2011 02:00 UTC)
[Scheme-reports] Internal definition shadowing problems Andre van Tonder (23 Apr 2011 23:19 UTC)
[Scheme-reports] Importing identifier more than once Andre van Tonder (23 Apr 2011 23:37 UTC)

Re: [Scheme-reports] ANN: first draft of R7RS small language available Vitaly Magerya 29 Apr 2011 13:33 UTC

Andy Wingo wrote:
> I don't know.  Like most of you, I've been programming scheme for a
> while, but the implications of lexical scope on keywords and modules
> have not even crossed my mind until an R6RS user reported a bug in our
> R6RS implementation, to this effect.

Folks, why do we at all match keywords (e.g. "else") lexically instead
of textually?

The ability to rename keyword on export is one stated benefit, but I'm
not sure this was/will ever be used. Moreover many implementations have
keyword and optional arguments, and I never heard anyone complaining
that you can't rename them.

Simplicity of syntax-rules is another benefit: now we've got one list of
identifiers that are matched lexically, we'd need one extra list for
those matched textually.

There are also historical reasons, i.e. it worked fine in R5RS where no
modules existed (provided you don't shadow "else" locally).

Any other reasons? Are these reasons compelling enough to go through the
trouble of binding & exporting auxiliary keywords in modules, risk local
shadowing, etc? I know WG1 voted on the issue, but I don't remember any
discussion on it.

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