Re: [Scheme-reports] Equality of records
Ray Dillinger 01 Mar 2012 19:15 UTC
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On 03/01/2012 10:38 AM, John Cowan wrote:
> Draft 6 requires that `equal?` recursively descend into records. However,
> the WG did not explicitly vote for this feature, nor is it mentioned
> in SRFI 9, which is our source document for records. In addition,
> R6RS explicitly forbids it, requiring that all objects except pairs,
> vectors, strings, and bytevectors be compared with `eqv?`.
I think that R6 is logically inconsistent in this point, and that
the prohibition is probably due to an oversight rather than due
to a decision.
If it requires pairs, vectors, and strings. to be recursively compared,
then it is not sensible to require records *not* to be recursively
compared.
The obvious implementation technique for any problem you'd use
records for, in fact, if you don't have records, *NECESSARILY*
uses one of the types that 'equal?' recursively compares.
Bear
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