[Scheme-reports] R7RS final draft - bug report for section 7.3 Derived expression types

[Joseph Wayne Norton <norton@x>]

Hello.

For R7RS final draft, the syntax-rules for the case derived _expression_ appears to be incorrect.  The order of the 4th <syntax rule> is incorrect.

The 4th <syntax rule> should be moved after the 5th <syntax rule> .  If not, the result1 pattern variable of the 4th <syntax rule> will incorrectly match with an => in the input.

Best regards,

Joe N.

p.s. Here is a corrected version:

 (define-syntax case

   (syntax-rules (else =>)

     ((case (key ...)

        clauses ...)

      (let ((atom-key (key ...)))

        (case atom-key clauses ...)))

     ((case key

        (else => result))

      (result key))

     ((case key

        (else result1 result2 ...))

      (begin result1 result2 ...))

     ((case key

-       ((atoms ...) result1 result2 ...))

-     (if (memv key '(atoms ...))

-         (begin result1 result2 ...)))

-    ((case key

        ((atoms ...) => result))

      (if (memv key '(atoms ...))

          (result key)))

     ((case key

        ((atoms ...) => result)

        clause clauses ...)

      (if (memv key '(atoms ...))

          (result key)

          (case key clause clauses ...)))

     ((case key

+       ((atoms ...) result1 result2 ...))

+     (if (memv key '(atoms ...))

+         (begin result1 result2 ...)))

+    ((case key

        ((atoms ...) result1 result2 ...)

        clause clauses ...)

      (if (memv key '(atoms ...))

          (begin result1 result2 ...)

          (case key clause clauses ...)))))

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