[j-devel] Re: The function (SETF MACRO-FUNCTION) is undefined.

[Adam W. <li...@co...>]

On Fri, 18 Feb 2005 10:25:51 -0800, Peter Graves wrote:

> On Sat, 19 Feb 2005 at 01:39:15 +1300, Adam Warner wrote:
>> CL-USER(1): (macro-function 'cond)
>> #<FUNCTION {153B2CB}>
>> CL-USER(2): (setf (macro-function 'c) (macro-function 'cond))
>> Debugger invoked on condition of type UNDEFINED-FUNCTION:
>>   The function (SETF MACRO-FUNCTION) is undefined.
>>
>> This example should make the COND macro accessible as C.
>>
>> <http://www.lispworks.com/documentation/HyperSpec/Body/f_macro_.htm>
> 
> Fixed.

Great stuff, thanks!!! From my perspective the only significant known
omission remaining is pretty printing of structures (i.e. :print-function
and :print-object, plus :constructor issues).* I fully understand fixing
this depends upon the eventual rewrite of the pretty printer.

I can use the SETF MACRO-FUNCTION functionality to clone many COMMON-LISP
macros in a case preserving package. Consider this lowercase lisp (lcl)
package:

(make-package "lcl" :use '())
(setf (macro-function '|lcl|::|cond|) (macro-function 'cl:cond))
(in-package "lcl")
(|cond| (1 "true")) => "true"

Thanks again,
Adam





* That is (just for reference):

CL-USER(1): (defstruct (test1 (:print-object print-test1)) st)
TEST1
CL-USER(2): (defun print-test1 (struct stream) (write-string "#<Hello, Peter!>" stream))
PRINT-TEST1
CL-USER(3): (make-test1)
#S(TEST1 :ST NIL)
[output should be #<Hello, Peter!>]

CL-USER(1): (defstruct (test2 (:constructor new-test2)) st)
TEST1
CL-USER(2): (new-test2)
#S(TEST2 :ST NIL)
CL-USER(3): (read-from-string "#S(TEST2 :ST NIL)")
Debugger invoked on condition of type UNDEFINED-FUNCTION:
  The function MAKE-TEST2 is undefined.
[That's because the constructor is actually NEW-TEST2]