Common Lisp Object System (CLOS) • Hacker News Board

Re: Common Lisp Object System (CLOS)

#11

Post by mikelevins » Wed, Nov 23, 2022, 12:46 PM UTC

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…

Maybe, though Alan Kay is certainly familiar with other object-oriented programming systems for Lisp that predate the design of CLOS.

Re: Common Lisp Object System (CLOS)

#12

Post by Avicebron » Wed, Nov 23, 2022, 12:48 PM UTC

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).

Re: Common Lisp Object System (CLOS)

#13

Post by retrac » Wed, Nov 23, 2022, 12:50 PM UTC

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…

"Object"? Though that creates ambiguity between definition and instances of the definition.

Re: Common Lisp Object System (CLOS)

#14

Post by zachbeane » Wed, Nov 23, 2022, 12:52 PM UTC

EdwardCoffin wrote: post #4

> I don’t know the exact implementation details of CLOS, but I feel that it can be easily replicated in C This makes me think he's barely scratched the surface of what CLOS has to offer.

The class and instance evolution protocols for starters seem not all that easy.

Re: Common Lisp Object System (CLOS)

#15

Post by mikelevins » Wed, Nov 23, 2022, 1:04 PM UTC

EdwardCoffin wrote: post #4

> I don’t know the exact implementation details of CLOS, but I feel that it can be easily replicated in C This makes me think he's barely scratched the surface of what CLOS has to offer.

"Easily" is a stretch, for sure, but John Wainwright developed a framework that he called "oic", for "Objects in C", that was a fairly substantial subset of CLOS.

I met him at OOPSLA ‘89 (or it might have been at AAAI) and introduced him to a couple of Apple developer guys, because I thought oic was cool. Whether because of that introduction or other reasons I’m not aware of, John ended up selling oic to Apple for use as the basis of the ScriptX object system, which was the programming language of the Kaleida Media Player (https://en.wikipedia.org/wiki/Kaleida_Labs).

Re: Common Lisp Object System (CLOS)

#16

Post by miroljub » Wed, Nov 23, 2022, 1:04 PM UTC

retrac wrote: post #13

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…

"Object"? Though that creates ambiguity between definition and instances of the definition.

You just nailed it :)

Maybe instead of "Class" and "Object" we should use "Definition" and "Instance".

Re: Common Lisp Object System (CLOS)

#17

Post by fhd2 » Wed, Nov 23, 2022, 1:05 PM UTC

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…

Same. I have quite a bit of OOP background, and I use CLOS, but it's clunky enough (compared to Ruby e.g.) to be a tool of last resort.

That said, I mostly work on CL code by myself, maybe CLOS is more useful to large teams, maybe that's where it really shines and why people praise it.

Re: Common Lisp Object System (CLOS)

#18

Post by _old_dude_ » Wed, Nov 23, 2022, 1:19 PM UTC

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…

"mold", but the mold is also an instance of a mold.

    i = c()
    print(i.a)
    i.a = 42
    print(i.a)

Re: Common Lisp Object System (CLOS)

#19

Post by Koshkin » Wed, Nov 23, 2022, 1:28 PM UTC

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…

Even C++ does not need ‘class,’ as it already has ‘struct’ that it inherited from C. (A saner language would just use the word ‘type.’)

Re: Common Lisp Object System (CLOS)

#20

Post by orthoxerox » Wed, Nov 23, 2022, 1:30 PM UTC

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…

From what I know about CLOS, it's a great tool if you have a tight-knit team of seasoned devs, but it's a giant sack of footguns otherwise. You can redefine so much about the object system that your codebase will instantly become unmaintainable.