On 9/28/09, Andrej Vodopivec <andrej.vodopivec at gmail.com> wrote:
> My analysis was not correct, the function isp is not used to query the
> assume database. Actually it is only used at the end of mevalp2 (in
> compar.lisp) and I cant find any input for which it would return
> something other than unknown or a lisp error. I don't really
> understand what it is supposed to do, but whatever it does it should
> check to see if the input is something that it can handle.
Well, the presence of 'kind in truep and falsep (called from isp)
suggests that it was intended to look at declared properties.
(I wasn't able to find an example which returns other than
unknown, however.)
I agree isp shouldn't cause an error, but I think enumerating
the operators for which it won't cause an error is mistaken;
it's likely that some inputs for which it should return t or nil
(if only we understood the db code) are therefore excluded.
It is better to put a test at the point at which the error is
now generated. (Actually it would be OK to wrap the body
of isp in some error-catching construct; that also allows for
correct inputs, if ever we figure out what they are.)
Robert Dodier