... and I can always CHANGE-CLASS, can't I? On Sun, Feb 7, 2021 at 9:46 AM Hans Hübner <hans.hueb...@gmail.com> wrote:
> Am So., 7. Feb. 2021 um 09:35 Uhr schrieb Manfred Bergmann < > manfred.bergm...@me.com>: > >> > Am 07.02.2021 um 09:23 schrieb Hans Hübner <hans.hueb...@gmail.com>: >> > >> > Am So., 7. Feb. 2021 um 09:20 Uhr schrieb Manfred Bergmann < >> manfred.bergm...@me.com>: >> > But fundamentally, you also can’t create an instance of a class in >> Common Lisp from just the symbol. The class definition must be known. >> > >> > This simply is untrue. You can use FIND-CLASS to find a class named by >> a symbol and then instantiate it. >> >> Well, OK. Sure. But when I do that I have again a dependency on the >> concrete class, or? And it would be similar as knowing the class right from >> the start. >> > > You don't. You have a dependency on the name of a class. The name could > refer to two entirely different classes between invocations of FIND-CLASS. > The name could also come from an external source. Thus, this is purely a > run-time dependency and it would be quite possible that FIND-CLASS returns > NIL if given a symbol that does not designate a currently-defined class. > -- Marco Antoniotti, Associate Professor tel. +39 - 02 64 48 79 01 DISCo, Università Milano Bicocca U14 2043 http://bimib.disco.unimib.it Viale Sarca 336 I-20126 Milan (MI) ITALY