Re: [Scheme-reports] Equality of records
Alaric Snell-Pym 02 Mar 2012 17:03 UTC
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On 03/02/2012 04:49 PM, John Cowan wrote:
> Ray Dillinger scripsit:
>
>> If it requires pairs, vectors, and strings. to be recursively compared,
>> then it is not sensible to require records *not* to be recursively
>> compared.
>
> One problem is that there is no portable way to ask if two records
> have the same type, which should certainly be a requirement for equality.
>
Also, records are meant to be opaque, unless you are actually given
access to their accessors (be it lexically or dynamically, as they're
first-class procedures). Allowing them to be compared with eqv? to see
if they are the same object with respect to mutation is handy, but
allowing comparison of their internals risks violating that encapsulation...
ABS
- --
Alaric Snell-Pym
http://www.snell-pym.org.uk/alaric/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
iEYEARECAAYFAk9Q/WEACgkQRgz/WHNxCGoVkQCeLNdM8sWW0ejZ7RKDmrA01Be6
YXwAn3FmBvVncNoNOl1b/YYO3/Lnr8gs
=oWx+
-----END PGP SIGNATURE-----
_______________________________________________
Scheme-reports mailing list
Scheme-reports@scheme-reports.org
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports