On Fri, Dec 30, 2005 at 07:58:15PM +0000, [EMAIL PROTECTED] wrote:
> I'm having trouble when I'm attempting to use macrolet. I've made a
> very small test case to illustrate the problem.
<snip>
> Here's the failure case, note that I'm using a comma-at expansion of
> "z":
>
> * (defun foo2 (x)
> (princ (format nil "listp(x) returns ~A." (listp x)))
> (macrolet ((fudge (z)
> `(list 1 2 3 ,@z)))
> (fudge x)))
>
> FOO2
>
> When foo2 is run, I get this error:
>
> * (foo2 '(1 2 3 4 a))
>
> Type-error in KERNEL::OBJECT-NOT-LIST-ERROR-HANDLER: X is not of
> type LIST
> [Condition of type TYPE-ERROR]
>
> Restarts:
> 0: [ABORT] Return to Top-Level.
>
> Debug (type H for help)
>
> (C::DYNAMIC-EXTENT-CLOSURE-ARGS (1 2 3 . X))
> Source: Error finding source:
> Error in function DEBUG::GET-FILE-TOP-LEVEL-FORM: Source file no
> longer exists: target:compiler/ir1tran.lisp.
> 0] 0
>
> If I change the comma-at to just just comma, look what happens:
>
> * (defun foo2 (x)
> (princ (format nil "listp(x) returns ~A." (listp x)))
> (macrolet ((fudge (z)
> `(list 1 2 3 ,z)))
> (fudge x)))
>
> FOO2
> * (foo2 '(2 4 5 a))
> listp(x) returns T.
> (1 2 3 (2 4 5 A))
>
> I don't understand why lisp doesn't believe x is a list--it is
> clearly a list. Is this a bug or am I not using macrolet correctly?
You're using Z incorrectly. Maybe this will help; note the FORMAT in
the definition of FUDGE:
CL-USER> (defun foo (x)
(macrolet ((fudge (z)
(format t "z is ~A~%" z)
`(list 1 2 3 ,@z)))
(fudge x)))
CL-USER> (compile 'foo)
z is X
Type-error in KERNEL::OBJECT-NOT-LIST-ERROR-HANDLER: X is not of
type LIST
[...]
Do you see? When expanding FUDGE, Z has the value X, not (1 2 3 4 A).
-- Larry
