Other way to a not supported inverse laplace transform with maxima?

On 4/21/2011 10:46 PM, Mark H Weaver wrote:
> Richard Fateman<fateman at eecs.berkeley.edu>  writes:
>>> I have attached a version of my preliminary patches, updated to work
>>> with current Maxima (5.24.0).  Note that the patch to laplac.lisp will
>>> require recompilation of the Maxima executable.
>> If you have written a source file called foo.lisp   that you wish to
>> use to change Maxima,
>> all you need to do is  load("foo.lisp").
>>
>> You do not need to recompile maxima.
> This was my expectation as well, but if I load("laplac.lisp"), even the
> unmodified version of it, this breaks $LAPLACE.  Henceforth, any attempt
> to use it results in the following error:
>
>    Error in COND [or a callee]: The variable PARM is unbound.
My guess is the same as yours, that declare-top is not doing what you 
need to do.
I don't know why, or whether it is particular to GCL.

This might fix it:

(defmfun $laplace (fun var parm)
   (declare (special parm var))   ;;  add this line
   (setq fun (mratcheck fun))


Thanks for your contributions!

RJF