Common Lisp: getting an error using readtable-case

Question

When I enter this at the REPL prompt:

(setf (readtable-case *readtable*) :invert)

I get this error message:

Error in SETF [or a callee]: Cannot expand the SETF form (READTABLE-CASE
                                                          *READTABLE*).

Why do I get this error?

Answer 1

(format nil "~A ~A" (lisp-implementation-type) (lisp-implementation-version)) says "Kyoto Common Lisp GCL 2.6.2". The result of (eq 'readtable-case 'cl:readtable-case) is T. What does this all mean please?

The second expression means you're using the correct symbol. The first indicates which Lisp implementation you're using: That should be GNU Common Lisp 2.6.2

After some search I found this message on the gcl-devel list saying ...

The problem appears to be this line:

(setf (readtable-case *readtable*) readcase)

in randomly-check-readability. I'd recommend this as the next ansi issue to resolve, since it's blocking the tests.

... with a subject line "ansi-tests in 2.7.0". The message is from 2004.

Bottom line: I guess you need a more recent or even* a different Lisp implementation.

(* as mentioned by Rainer Joswig the issue also affects the current 2.6.12 release)

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I guess all major Lisp implementations support this. CLISP 2.49 does, SBCL and CCL probably do, as far as I know ECL does also.