6 ms·

A lot of the recent trend towards OOP-bashing comes from bad implementations of OOP, just as bashing design patterns is more to do with badly thought out archit

A lot of the recent trend towards OOP-bashing comes from bad implementations of OOP, just as bashing design patterns is more to do with badly thought out architectures and overuse of those patterns. In fact, the origins of OOP are basically what we would now call microservice architecture (CSP-inspired languages like Go being a specialisation of this). Each service can be as stateless or as stateful as it needs to be (without shared state) and services should be loosely coupled. That's quite different to most large-scale OOP architectures, but it is possible to code in that style in any OOP language. Heavy reliance on inheritance for code reuse is a whole problem class in itself that again has little to do with OOP and lots to do with the influence of C++.

archagon 12y ago
It seems to me that you can't really do message passing in most languages with high efficiency? (Objective-C and Swift being the exceptions.)
- Joeri 12y ago
  I think it's a bit charitable to call what Objective C does to be "message passing". The messages are not asynchronous and have only a single recipient, so in practice I would say they're method calls with late binding.
  - archagon 12y ago
    You can do one-to-many messages via notifications, though it's less elegant.
  - mpweiher 12y ago
    However, they can easily be made asynchronous and address multiple recipients. See Higher Order Messaging[1][2], first implemented in Objective-C[3]. So for example: [[myView onMainThread] setNeedsDisplay:YES]; result = [[someObject future] someMessage:arg]; combined = [[prefixes collect] stringByAppendingString:[suffixes each]]; The reason this is easy in Objective-C is because its brand of message passing is just (barely) powerful enough to qualify as message passing. In fact, if you squint just a little, you can see it as fully reified message passing with the common-case (a synchronous method is invoked) optimized. [1] http://en.wikipedia.org/wiki/Higher_order_message http://en.wikipedia.org/wiki/Higher_order_message [2] http://www.metaobject.com/papers/Higher_Order_Messaging_OOPSLA_2005.pdf http://www.metaobject.com/papers/Higher_Order_Messaging_OOPS... [3] https://github.com/mpw/MPWFoundation https://github.com/mpw/MPWFoundation
  - xsmasher 12y ago
    At least you can redirect messages to another recipient, and write a handler for "unhandled messages." Impossible with c++, at least with standard method calls.
- rurban 12y ago
  Rather the opposite. Almost all HPC (high-performance computing) systems use message passing and not shared memory. The fastest and imho best unix-like kernel L4 is entirely MP based. So if you want to embrace high performance (and concurrent), go message passing. Alan Kay's favor of late binding does not help performance, as method lookup at run-time dominates the cost then, but the fast systems are early bound, i.e. typed.
  - seanmcdirmid 12y ago
    Well, you are discounting CUDA, which has been seen as suited for many tasks when compared to MPI. Of course, you can use MPI and CUDA together (people are working on that), which you then have messaging between nodes and shared memory (via GPU-style SIMD) within. Of course, you are probably referring to NUMA, but people still actually use that. Pure OO isn't very much desired in the HPC world, but then neither is pure FP.
alan82 12y ago
In sports, training coaches sometimes forbid to use some play element. In OOP classes there should be an assignment to design a system without inheritance. Just to show what is most important in OOP.
- Jare 12y ago
  I was taught OOP using Modula-2 in 1989, by defining structures and functions that took a pointer to the struct as first parameter. No inheritance goodies! I used that style in C until 1996 when I definitely moved to C++. Probably why I am not terribly dismissive of OOP but very much of things like inheritance trees, the Java OOP style, and the overuse of GoF in architecture, literature and especially programming discussions.
- vince_refiti 12y ago
  In Ada, I remember reading that you can limit the inheritance depth.
- thewarrior 12y ago
  How would you design something like : Person --> Full Time Employee --> Manager Person --> Contract Employee Without inheritance assuming that salary calculation is the only thing which differentiates them.
  - derefr 12y ago
    Something like... Person HAS A IEmploymentRelationship ContractEmployment IMPLEMENTS IEmploymentRelationship FullTimeEmployment IMPLEMENTS IEmploymentRelationship FullTimeEmployment HAS A IDirectReport Manager HAS A Person Manager IMPLEMENTS IDirectReport And then salary() is a polymorphic function declared by the IEmploymentRelationship interface, where FullTimeEmployment instances use the manager somehow, and ContractEmployment doesn't. You can even put some sugar on that by having a salary() function on Person that calls the salary() function on its IEmploymentRelationship—but I wouldn't, for the same reason I wouldn't denormalize a relational database.
    - 12y ago
tailrecursion 12y ago
If we redefine the word "OOP:object" to mean process-with-mailbox, and redefine the word "OOP:message" to mean asynchronous message passing, then objects and messages make sense and are useful. Those are not Smalltalk's definitions -- even though I think you're right on about Alan Kay's original inspiration -- and confusion can arise if we redefine terms.
rumcajz 12y ago
Alan Kay may have coined the term, but OOP (as any other word or term) is what people believe it to be. Which is pretty far from CSP.
trhway 12y ago
>A lot of the recent trend towards OOP-bashing comes from bad implementations of OOP, just as bashing design patterns is more to do with badly thought out architectures and overuse of those patterns. sorry, but this is no true Scotsman fallacy. All these "bad implementations" is OOP, real OOP, not some idealized ephemeral non-existent Avalon. If an idea easily and more frequently than not lands itself to the bad implementations then there is something wrong with the idea. (I happen to come from a country which was pursuing what was looking like a pretty good idea - communism - which has got a lot of bashing during recent decades, due to "bad implementations" i guess, and as result it was critically rethought and now we know what it is not a good idea really)

archagon 12y ago

It seems to me that you can't really do message passing in most languages with high efficiency? (Objective-C and Swift being the exceptions.)

Joeri 12y ago
I think it's a bit charitable to call what Objective C does to be "message passing". The messages are not asynchronous and have only a single recipient, so in practice I would say they're method calls with late binding.
- archagon 12y ago
  You can do one-to-many messages via notifications, though it's less elegant.
- mpweiher 12y ago
  However, they can easily be made asynchronous and address multiple recipients. See Higher Order Messaging[1][2], first implemented in Objective-C[3]. So for example: [[myView onMainThread] setNeedsDisplay:YES]; result = [[someObject future] someMessage:arg]; combined = [[prefixes collect] stringByAppendingString:[suffixes each]]; The reason this is easy in Objective-C is because its brand of message passing is just (barely) powerful enough to qualify as message passing. In fact, if you squint just a little, you can see it as fully reified message passing with the common-case (a synchronous method is invoked) optimized. [1] http://en.wikipedia.org/wiki/Higher_order_message http://en.wikipedia.org/wiki/Higher_order_message [2] http://www.metaobject.com/papers/Higher_Order_Messaging_OOPSLA_2005.pdf http://www.metaobject.com/papers/Higher_Order_Messaging_OOPS... [3] https://github.com/mpw/MPWFoundation https://github.com/mpw/MPWFoundation
- xsmasher 12y ago
  At least you can redirect messages to another recipient, and write a handler for "unhandled messages." Impossible with c++, at least with standard method calls.
rurban 12y ago
Rather the opposite. Almost all HPC (high-performance computing) systems use message passing and not shared memory. The fastest and imho best unix-like kernel L4 is entirely MP based. So if you want to embrace high performance (and concurrent), go message passing. Alan Kay's favor of late binding does not help performance, as method lookup at run-time dominates the cost then, but the fast systems are early bound, i.e. typed.
- seanmcdirmid 12y ago
  Well, you are discounting CUDA, which has been seen as suited for many tasks when compared to MPI. Of course, you can use MPI and CUDA together (people are working on that), which you then have messaging between nodes and shared memory (via GPU-style SIMD) within. Of course, you are probably referring to NUMA, but people still actually use that. Pure OO isn't very much desired in the HPC world, but then neither is pure FP.

alan82 12y ago

In sports, training coaches sometimes forbid to use some play element. In OOP classes there should be an assignment to design a system without inheritance. Just to show what is most important in OOP.

Jare 12y ago
I was taught OOP using Modula-2 in 1989, by defining structures and functions that took a pointer to the struct as first parameter. No inheritance goodies! I used that style in C until 1996 when I definitely moved to C++. Probably why I am not terribly dismissive of OOP but very much of things like inheritance trees, the Java OOP style, and the overuse of GoF in architecture, literature and especially programming discussions.
vince_refiti 12y ago
In Ada, I remember reading that you can limit the inheritance depth.
thewarrior 12y ago
How would you design something like : Person --> Full Time Employee --> Manager Person --> Contract Employee Without inheritance assuming that salary calculation is the only thing which differentiates them.
- derefr 12y ago
  Something like... Person HAS A IEmploymentRelationship ContractEmployment IMPLEMENTS IEmploymentRelationship FullTimeEmployment IMPLEMENTS IEmploymentRelationship FullTimeEmployment HAS A IDirectReport Manager HAS A Person Manager IMPLEMENTS IDirectReport And then salary() is a polymorphic function declared by the IEmploymentRelationship interface, where FullTimeEmployment instances use the manager somehow, and ContractEmployment doesn't. You can even put some sugar on that by having a salary() function on Person that calls the salary() function on its IEmploymentRelationship—but I wouldn't, for the same reason I wouldn't denormalize a relational database.
  - 12y ago

tailrecursion 12y ago

If we redefine the word "OOP:object" to mean process-with-mailbox, and redefine the word "OOP:message" to mean asynchronous message passing, then objects and messages make sense and are useful. Those are not Smalltalk's definitions -- even though I think you're right on about Alan Kay's original inspiration -- and confusion can arise if we redefine terms.

rumcajz 12y ago

Alan Kay may have coined the term, but OOP (as any other word or term) is what people believe it to be. Which is pretty far from CSP.

trhway 12y ago

>A lot of the recent trend towards OOP-bashing comes from bad implementations of OOP, just as bashing design patterns is more to do with badly thought out architectures and overuse of those patterns. sorry, but this is no true Scotsman fallacy. All these "bad implementations" is OOP, real OOP, not some idealized ephemeral non-existent Avalon. If an idea easily and more frequently than not lands itself to the bad implementations then there is something wrong with the idea. (I happen to come from a country which was pursuing what was looking like a pretty good idea - communism - which has got a lot of bashing during recent decades, due to "bad implementations" i guess, and as result it was critically rethought and now we know what it is not a good idea really)