rcbamhl@eutrc3.urc.tue.nl (Marc Heijligers) (12/12/89)
Hello,
I think I have found a compile error in Macintosh Allegro Common Lisp
version 1.2.2. It has to do with the dynamic scope of special variables.
The problem is as follows; I want to share a variable between two functions,
but must not be a global variable. So I do the following:
(defun test ()
(let ((a 1))
(declare (special a))
(test1)))
(defun test1 ()
(declare (special a))
(print a))
Calling (test) results in printing 1. This is correct. When I try more than
one variable, I try:
(defun test ()
(let ((a 1))
(declare (special a)
(special b))
(test1)))
(defun test1 ()
(declare (special a)
(special b))
(print a))
Calling (test) results in an error!!
> Error: Unbound variable: A .
> While executing: TEST1
This should not! In Steele the form for declare is (declare {decl-spec}*).
So I assume you can use (special ..) more than once.
When I try the example above without compiling, it works correct. This
is an error; a program should work interpreted the same way as compiled
(see page 438 of Steele).
By the way, the following form works correct:
(defun test1 ()
(declare (special a b))
(print a))
(defun test ()
(let ((a 1))
(declare (special a b))
(test1)))
By the way, I discovered this problem when trying to port a program made in
Lucid Common Lisp to Allegro Common Lisp.
I hope I'm not wrong about this error. Anyone any suggestions?
By the way, how much faster will the new version of MACL be?
Marc Heijligers
rcbamhl@eutrc3.urc.tue.nl