equivalent of "this" in goops?
I'm using guile 1.6.x,and doing network mapping. In a class representing a node, I want to have a slot with an init-thunk, and I would like to call a procedure with the class object as an argument. The slot holds a class object which is basically a hash table of links in a network, and it needs the node object so it can hash on 'other end node id'. So, I'd like to pass 'this' in c++ terms, and I don't see how to do that from reading goops.info. I realize there are issues with the class not being fully initialized, and in my case that's safe since I'm just storing the object in a variable and not using it until a link is added, which doesn't happen during object initialization. Thus I realize that what I want to do is vaguely unschemely. My fallback is to initialize the linkset on first use, or after object createion, or something like that. -- Greg Troxel <[EMAIL PROTECTED]> ___ Guile-user mailing list Guile-user@gnu.org http://lists.gnu.org/mailman/listinfo/guile-user
Re: equivalent of "this" in goops?
Greg Troxel <[EMAIL PROTECTED]> writes: > I'm using guile 1.6.x,and doing network mapping. > > In a class representing a node, I want to have a slot with an > init-thunk, and I would like to call a procedure with the class object > as an argument. The slot holds a class object which is basically a > hash table of links in a network, and it needs the node object so it > can hash on 'other end node id'. > > So, I'd like to pass 'this' in c++ terms, and I don't see how to do > that from reading goops.info. I realize there are issues with the > class not being fully initialized, and in my case that's safe since > I'm just storing the object in a variable and not using it until a > link is added, which doesn't happen during object initialization. > Thus I realize that what I want to do is vaguely unschemely. FWICT (not being a GOOPS expert), this is not possible without extending GOOPS: the init-thunk of a slot is specified at class creation time, and the earliest time "this" is avaiable is in the "initialize" generic. However, since the init-thunk is called at initialization time, "this" would be available at the time it is run, but there is no way to pass it, since the init-thunk, is, well, a thunk ;). I could imagine a init-function (name to be argued), which gets passed all arguments from "initialize" could be a useful extension. > My fallback is to initialize the linkset on first use, or after object > createion, or something like that. > Given a GOOPS with this hypothetical extension is far from official release ;), a workaround is probably the only feasibly short-term solution (given my assumtion that this is not possible with current GOOPS). Cheers, Rotty -- Andreas Rottmann | [EMAIL PROTECTED] | [EMAIL PROTECTED] | [EMAIL PROTECTED] http://yi.org/rotty | GnuPG Key: http://yi.org/rotty/gpg.asc Fingerprint | DFB4 4EB4 78A4 5EEE 6219 F228 F92F CFC5 01FD 5B62 The best way to accelerate a Windows machine is at 9.81 m/s^2 ___ Guile-user mailing list Guile-user@gnu.org http://lists.gnu.org/mailman/listinfo/guile-user
Re: equivalent of "this" in goops?
Andreas Rottmann wrote: Greg Troxel <[EMAIL PROTECTED]> writes: In a class representing a node, I want to have a slot with an init-thunk, [...] So, I'd like to pass 'this' in c++ terms, and I don't see how to do that from reading goops.info. FWICT (not being a GOOPS expert), this is not possible without extending GOOPS: the init-thunk of a slot is specified at class creation time, and the earliest time "this" is avaiable is in the "initialize" generic. However, since the init-thunk is called at initialization time, "this" would be available at the time it is run, but there is no way to pass it, since the init-thunk, is, well, a thunk ;). I could imagine a init-function (name to be argued), which gets passed all arguments from "initialize" could be a useful extension. Absolutely right. Your best bet at this point is to customize the initialize method for the class: (define-method (initialize (this ) initargs) (next-method) (slot-set this 'name-of-slot-with-init-thunk (init-function this))) (It's probably also possible to use the MOP to support #:init-proc as a new slot option, but that would require more thought.) Regards, Neil ___ Guile-user mailing list Guile-user@gnu.org http://lists.gnu.org/mailman/listinfo/guile-user
