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DEFSTRUCT copier query
Date: Monday, 3 November 1986 10:17-EST
From: <samalone at ATHENA.MIT.EDU>
Re: DEFSTRUCT copier query
(copy-bread (make-rye-bread :state 'stale :seeded-p nil))
A: #S(RYE-BREAD :STATE STALE :SEEDED-P NIL)
B: #S(BREAD :STATE STALE)
This unclarity has been pointed out before, but there didn't seem to
be any real consensus. I agree that it seems to be semantically
cleaner to return an object of the same type as the argument. I think
the only reasonable alternative would be to say that it is erronous.
Since there doesn't seem to be any support for B, no one can complain
if you implement A, although it may not be required for Common Lisp.