Michael Sperber scripsit:

> If the criterion is indeed how long it took implementations to
> move to R5RS to R6RS, I'd welcome you to look at how long it took
> implementations to move from R4RS to R5RS.  If that's a fact that
> measures community acceptance for a standard, then R5RS was an abysmal
> failure, and you should start with something earlier.

It's not about "how long", it's about whether the implementation is going
there or not.  It's not clear to me whether Scheme 9 predates R5RS or not,
but it is the only currently maintained implementation that targets R4RS.
The other implementations marked with % don't target any Scheme standard
at all (in the case of Owl Lisp, the subset of R5RS that excludes mutation
is targeted).

> What's the criterion for "attempt"?

The same as any other sort of attempt.  You attempt something if you
have the intention to do it and take steps toward doing it.  The Guile
maintainers have (as they have stated) no intention of supporting R6RS
in the future.  The Scheme48 developers stated an intention, but have
taken no publicly visible concrete steps.  Neither one, therefore,
is attempting to provide R6RS.  By the same criteria, the eight
implementations I mentioned *are* attempting it.

> Anyway, I've said my part, and this is the extent to which I care.

Very well.

> It's your funeral.

I'm taking steps to postpone that event.

--
John Cowan  cowan@ccil.org  http://ccil.org/~cowan
If I have seen farther than others, it is because I am surrounded by dwarves.
        --Murray Gell-Mann

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