Re: CLOS: precedence of classes

[Pascal POIZAT - DEA Info <poizat@ensinfo.univ-nantes.fr>]

If you do

c1->()
c2->c1
c3->c1,c2
(inheritance links) then CLOS generates a cycling precedence list for c3.
Don't forget that it will add an extra link between c1->c2 thus making (c1,c2) a cycle.


                        c1
                     /\       /\
                     |        |
                    c2 <---   c3
this is what you did.
Then CLOS modifies this to obtain:
                        c1
                  /\    |    /\
                  |    \/    |
                     c2  <-- c3
and here there is a cycle between c1 and c2.
This is because you specified c1 before c2 in c3's inheritance list.
When you say that c inherits from c1 c2 c3 ... ci ci+1 ... cn
then you create implicit (for CLOS) links between c1 and c2, c2 and c3, ..., ci and ci+1,
cn-1 and cn.

Just try modifying class3 by making it like this:
(defclass class3 (class2 class1) ()) it should work.

Pascal Poizat
DEA Informatique, Nantes, France
(pre PhD year in Computer Science)
Applying Rewriting to Object Specifications using CLOS.

PS: thanks for mailing me the place where to find the last version of CLISP-HIGH.

poizat@ensinfo.univ-nantes.fr

PS2: I mailed this directly to you, since if you receive hundreds of answers you
could join them and then mail them to the mailing-list.