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From: Matt K. <mat...@gm...> - 2024-03-02 15:32:56
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Hi, In SBCL 2.4.2, standard-char-p no longer returns t on a standard character input. Apparently it now returns that input, as defined in file src/code/target-char.lisp of the SBCL 2.4.2 source distribution. This behavior is of course Common Lisp compliant, since every value is a so-called generalized Boolean. That said, our ACL2 development has assumed for more than 30 years that predicates return Booleans except when specified otherwise, like member (not looking here for an argument about whether that assumption was proper) -- and we've never seen that assumption violated by any Common Lisp implementation that can host ACL2 (currently 6 of them, including SBCL). So, I'll ask: Might that change be reversed in the next SBCL release? Since the change wasn't mentioned in the "changes in sbcl-2.4.2 relative to sbcl-2.4.1" emailed to the list, at least not mentioned explicitly, I'm hoping that the change was inadvertent. Of course, if there are other such examples I'd be very interested to learn of them. Thanks, Matt |