[R6RS] `eqv?' on immutable records

William D Clinger will at ccs.neu.edu
Mon May 14 14:42:39 EDT 2007


Kent wrote:
> Incidentally, I'm guilty of defining record types with no fields to be
> used only for their object identity, e.g., defining
> 
>   (define-record-type label)
> 
> and counting on each call to make-label returning a new object
> distinguishable from all others via eq?.

That strikes me as the moral equivalent of counting
on each call to list or vector or string to return
a new object that's distinguishable (via eq?) from
the results of all other calls to list or vector or
string.

In other words, code that does that seems just plain
buggy to me.  I don't think the R6RS is obliged to
convert buggy R5RS code into correct R6RS code, or
to convert buggy R5RS+records code into correct R6RS
code.

Will



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