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Re: Minor last-minute issues

This page is part of the web mail archives of SRFI 105 from before July 7th, 2015. The new archives for SRFI 105 contain all messages, not just those from before July 7th, 2015.

On Wed, Sep 19, 2012 at 10:22 AM, John Cowan <cowan@xxxxxxxxxxxxxxxx> wrote:
>> For Scheme as of R6RS, [x ...] means (x ...), so that's what SRFI-105
>> (which is specific to Scheme) says.
> R6RS imposes this requirement, but R7RS does not.  See
> http://trac.sacrideo.us/wg/wiki/BracketsBraces for details of which
> Schemes do what with brackets.  You can't just say "Brackets mean what
> they mean in Scheme", because there is and will be no unified meaning.
> Since you're providing a full implementation modulo the change to
> the readtable, you need to make some decision for the purposes of that
> implementation, and it's not clear to me what it should be.  The advantage
> of Kawa's $bracket-list$ convention is that it can be mapped to treating
> [] like (), but it can be mapped to something else too, at the will of
> the user.

Hmm, how about "unprefixed square brackets mean whatever they mean
normally in the Scheme implementation; if the Scheme implementation
does not have any particular intended meaning, it should use the R6RS

I don't really see "we need a unified meaning for unprefixed [ ]" to be an
important requirement; basically, the intent is that unprefixed [ ] means
the same as [ ] outside of n-expr syntax.

After all, it seems that currently portable Scheme code can't depend on
any particular interpretation for [ ] anyway, so it's not really being worse
off - and I dunno, maybe it'll help adoption a bit?

I'll let David consider this first, in any case the above is what is intended
for unprefixed [ ] in the general syntax of n-expressions.