Re: [Scheme-reports] Formal Comment: R7RS 'eqv?' cannot be used for reliable memoization

[John Cowan <cowan@x>]

Alex Shinn scripsit:

> We are actively fixing flaws, which so far have been limited
> to minor editorial changes.

http://trac.sacrideo.us/wg/wiki/SeventhDraftEditorialCorrections
specifies these in general terms: details on request.  

> The problem with the eqv? issue is nobody agrees on the right
> definition.  Some people will be unhappy no matter what we specify.
> I think it's a slightly odd spec only in that it ties us to IEEE 754,
> but disagree that it's "broken" in any serious way.

How about this compromise:  simply remove the clause defining `eqv?` on
non-IEEE flonums?  It is arguably not a proper domain for standardization
anyway, since there are no such implementations today.  That would allow
future implementations to return `#t` or `#f` at their discretion.

I think this is at the outer limit of what can be done by editorial
correction, but still barely possible.  It is IMHO in the spirit of the
"same-bits" proposal that the WG adopted.

> We could of course revise the wording since some people find it
> confusing, and say that the rule applies to something to the affect of
> "IEEE or any approximation thereof".

I have changed "conforming to" to "implemented in the style of",
which I think eliminates that problem.

> If there is anything else you'd like to bring up, please do so.
> Better late than never.  If there truly is a serious flaw we can make a
> rush vote, but it will be too late once the ratification process starts.

+1000

-- 
So they play that [tune] on                     John Cowan
their fascist banjos, eh?                       cowan@x
        --Great-Souled Sam                      http://www.ccil.org/~cowan

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