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Common Lisp Object System (CLOS)

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Re: Common Lisp Object System (CLOS)

#21

Post by Koshkin »

dj_mc_merlin wrote: post #7

Meh.. I code in Common Lisp at home and Java professionally and I've never understood why people praise the CLOS so much. Like the author says, 99% of the time you don't have a reason to use OOP, and the few times you do you'd prefer to use as little as possible to keep everything sane. It's also one of the few parts of CL which are not optimized well by default, using structs or other basic data structures instead o…

> rather than having to create interfaces

I don’t know about that. To me, interfaces is the best thing since sliced bread, “OOP” or not. In particular, they bring some sanity to the design in the modern C++, where you would use templates in the lower level parts of the application, for performance, and interfaces at the higher level, for sanity.

Re: Common Lisp Object System (CLOS)

#22

Post by [deleted] »

dj_mc_merlin wrote: post #7

Meh.. I code in Common Lisp at home and Java professionally and I've never understood why people praise the CLOS so much. Like the author says, 99% of the time you don't have a reason to use OOP, and the few times you do you'd prefer to use as little as possible to keep everything sane. It's also one of the few parts of CL which are not optimized well by default, using structs or other basic data structures instead o…

[deleted]

Re: Common Lisp Object System (CLOS)

#23

Post by TurboHaskal »

dj_mc_merlin wrote: post #7

Meh.. I code in Common Lisp at home and Java professionally and I've never understood why people praise the CLOS so much. Like the author says, 99% of the time you don't have a reason to use OOP, and the few times you do you'd prefer to use as little as possible to keep everything sane. It's also one of the few parts of CL which are not optimized well by default, using structs or other basic data structures instead o…

You cannot use Common Lisp without the CLOS. The fact that you can delude yourself into thinking that most of the time you don't have a reason to use it is what makes it so great.

Re: Common Lisp Object System (CLOS)

#24

Post by signa11 »

ngcc_hk wrote: post #6
bradrn wrote: post #2

Alan Kay’s immortal quote about OOP: > OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things. It can be done in Smalltalk and in LISP. There are possibly other systems in which this is possible, but I'm not aware of them. [ http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay... ] His reference to ‘LISP’ is, of course, referring to C…

And the message idea live on objective c and lisp, but not the other c++ system.

don’t forget erlang !

Re: Common Lisp Object System (CLOS)

#25

Post by phtrivier »

bradrn wrote: post #2

Alan Kay’s immortal quote about OOP: > OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things. It can be done in Smalltalk and in LISP. There are possibly other systems in which this is possible, but I'm not aware of them. [ http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay... ] His reference to ‘LISP’ is, of course, referring to C…

I bet Erlang/OTP also fits (which the added niceties of potentially distributing the object graph.)

Re: Common Lisp Object System (CLOS)

#26

Post by medo-bear »

isnt this just a small journal entry saying, "i started to learn clos and i think i like it". i dont see any siginificant information about why clos is great here. doing general oop in lisp is powerful from the get-go because you can update classes and instances interactively. you will use clos for this basic functionality. however clos also allows you to extend the oop ideas in directions that are just not available in other languages

Re: Common Lisp Object System (CLOS)

#27

Post by mikelevins »

dj_mc_merlin wrote: post #7

Meh.. I code in Common Lisp at home and Java professionally and I've never understood why people praise the CLOS so much. Like the author says, 99% of the time you don't have a reason to use OOP, and the few times you do you'd prefer to use as little as possible to keep everything sane. It's also one of the few parts of CL which are not optimized well by default, using structs or other basic data structures instead o…

I praise CLOS because I've used it quite a bit and I like it.

CLOS is an object-system construction kit as much as it is an object system. I generally like to solve problems by building a language in which the solution is simple and straightforward to express, and CLOS provides handy tools for defining data structures and suites of operations on them that facilitate that approach.

I also like to work by livecoding, and that sometimes means redefining types that have live instances. If my types are CLOS classes, the Lisp will automatically catch changed definitions and will update existing instances to conform to the new definition. That's awfully helpful in a livecoding context.

CLOS has also come in handy when I needed to build novel systems of data types and function dispatch. For example, Ive worked on several knowledge-representation systems over the years, and it's been useful to have CLOS features for constructing novel inheritance schemes, access controls, truth-maintenance, persistence mechanisms, and so on.

So I've used CLOS quite a bit over the years. Some tools vex me more every time I have to use them. Others are a greater pleasure to work with each time. In my experience, CLOS has been a tool of the second kind.

Re: Common Lisp Object System (CLOS)

#28

Post by Koshkin »

Avicebron wrote: post #12
timonoko wrote: post #9

One thing bad is the word 'class'. What it is supposed to even mean? It was some fancy concept by stupid Normen when defining Simula. My Simula teacher said that you could just translate it as "design" as in "design of car and its implementation". Anyways Python's "class" is even worse: class c: a=10 print c.a c.a=13 print c.a I cannot think any English word to replace the "class". The word I am thinking of could be…

maybe superset or subset works as a translation? (in the math sense superset).

“In the math sense” a better term would be ‘category’ :)

Re: Common Lisp Object System (CLOS)

#29

Post by headhasthoughts »

TurboHaskal wrote: post #23
dj_mc_merlin wrote: post #7

Meh.. I code in Common Lisp at home and Java professionally and I've never understood why people praise the CLOS so much. Like the author says, 99% of the time you don't have a reason to use OOP, and the few times you do you'd prefer to use as little as possible to keep everything sane. It's also one of the few parts of CL which are not optimized well by default, using structs or other basic data structures instead o…

You cannot use Common Lisp without the CLOS. The fact that you can delude yourself into thinking that most of the time you don't have a reason to use it is what makes it so great.

You absolutely can use it without CLOS. It was an afterthought poorly bolted on that was worse than its predecessor in most ways as to be portable. It didn't exist when CLtL1 was written and barely existed when CLtL2 was released.
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