Thread View: comp.lang.clos
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Started by Fernando Mato Mira
Thu, 29 Oct 1992 10:44
CLOS data structures shelf
Author: Fernando Mato Mira
Date: Thu, 29 Oct 1992 10:44
Date: Thu, 29 Oct 1992 10:44
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I have noticed that you can find almost all the high level tools you want for LISP in the public domain, but is there any source for a good set of data structure classes (gap lists, tree varieties, whatever)? If such a thing does not exist, maybe it would be a good idea to organize a shelf accessible by ftp somewhere. Unless somebody can provide a pretty complete library with a consistent interface which has also been well coded, I think that it would be better to make it grow from the list/array level, which would require some discussion. It will require some work to adapt contributions to the "standardized" classes, but you will not need to have a dozen versions of some basic tree class differing fundamentally in their interface and implementation to be able to use at the same time, say, the restricted quadtrees provided by one person, the octress given by a second one, and the mip-maps developed by a third. In OO programming, classes are part of the language, and their standardization is something that deserves the same attention as that of the MOP or CLOS itself. -- Fernando D. Mato Mira Computer Graphics Lab Swiss Federal Institute of Technology matomira@di.epfl.ch NeXTMail : matomira@lignext.epfl.ch FAX : +41 (21) 693 - 5328
Re: CLOS data structures shelf
Author: Arun Welch
Date: Thu, 29 Oct 1992 14:55
Date: Thu, 29 Oct 1992 14:55
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In article <1992Oct29.114419@disuns2.epfl.ch> matomira@disuns2.epfl.ch (Fernando Mato Mira) writes:
I have noticed that you can find almost all the high level tools you
want for LISP in the public domain, but is there any source for a good
set of data structure classes (gap lists, tree varieties, whatever)?
If such a thing does not exist, maybe it would be a good idea to
organize a shelf accessible by ftp somewhere.
I'm willing to provide an ftp area for CLOS-based code, along with the
archives of this mailing list.
...arun
CommonLoops-request
----------------------------------------------------------------------------
Arun Welch
Lisp Systems Programmer, Lab for AI Research, Ohio State University
welch@cis.ohio-state.edu
Re: CLOS data structures shelf
Author: Daniel LaLiberte
Date: Thu, 29 Oct 1992 19:41
Date: Thu, 29 Oct 1992 19:41
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Oh, what the heck, I'm not proud. Below is the header from my CLOS-based dag.lisp code. It is certainly not the ultimate in clean code, but I find it pretty useful and it is somewhere to start. Please include it in the archive. Dan LaLiberte liberte@cs.uiuc.edu (Join the League for Programming Freedom: lpf@uunet.uu.net) "If we don't succeed, we run the risk of failure. -- Vice President Dan Quayle." --------- DAG (directed acyclic graph) structures are made of dag-nodes and dag-groups. dag-group is a subclass of dag-node, and dag-group instances list all the sub-nodes of the group. dag-nodes list all parents, which strictly speaking is not part of a dag data structure, so this should probably be called something like a dag-with-backlinks structure. One can look at the parent references as forming an upside down dag structure, but CLOS doesnt deal well with unshared slots with the same name. Also, dag-group might be implemented as a subclass of a tree class. The difference, of course, is that dag-nodes may be shared by multiple parents. To support traversals, an external hash table is used (see tally class below). This permits multiple simultaneous traversals, and avoids an extra pass to unvisit. It is also safer. One problem is the wasted space of a hash table each time a traversal occurs. There is alot of redundancy in the traversal functions. How can I simplify them?
Re: CLOS data structures shelf
Author: Fernando Mato Mira
Date: Fri, 30 Oct 1992 13:07
Date: Fri, 30 Oct 1992 13:07
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I am writing posting this for somebody whose news server is momentariliy down: >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< I think your idea is really good. A preliminary discussion should be started in order to decide what should go in the library(ies) and what interfaces should be provided. A first pointer could be the cl-utilities library maintained at CMU by Mark Kantrowitz (Mark_Kantrowitz@glinda.oz.cs.cmu.edu) Marco Antoniotti ------------------------------------------------------------------------------- Robotics Lab | e-mail: marcoxa@cs.nyu.edu Courant Institute | office: 1219 NYU | tel. #: (212) 998 3370 ...e` la semplicita` che e` difficile a farsi. ...it is simplicity that is difficult to make. B. Brecht New York is real! The rest is done with mirrors. ?. WXYZ
CLOS Programming Methodology (was: CLOS shelf)
Author: Fernando Mato Mira
Date: Thu, 05 Nov 1992 10:15
Date: Thu, 05 Nov 1992 10:15
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It would be good if we could come up with a set of guidelines for producing good and reusable CLOS classes. Any personal experiences are wellcome to the discussion. Reports on bugs using CLOS and packages on different implementations will be helpful, too. -- Fernando D. Mato Mira Computer Graphics Lab Swiss Federal Institute of Technology matomira@di.epfl.ch NeXTMail : matomira@lignext.epfl.ch FAX : +41 (21) 693 - 5328
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