3 ms·

Simula 67 is much closer to the mainstream OO concepts we see in C++, Java, C# and Python than Smalltalk, or let alone Self. ST was the first dynamically typed

by Rochus 4y ago

Simula 67 is much closer to the mainstream OO concepts we see in C++, Java, C# and Python than Smalltalk, or let alone Self. ST was the first dynamically typed OO language (scripting language actually) though.

vidarh 4y ago
Ii is, because it inspired both the Smalltalk branch and the more mainstream OO languages, and hence it makes sense to consider it as a possible ur-language in that sense. Smalltalk is a branch, but it's an important enough branch introducing important enough new concepts that unlike with Self I wouldn't have an issue with people considering Smalltalk it's own ur-language, and because I agree with you that Simula at least on the surface will seem more familiar to people familiar with ALGOL-derived languages with OO mechanisms than to Smalltalk. Self, on the other hand, is less important for its concepts (ok, so it has prototypes instead of classes, but classes in Smalltalk are also objects, so I don't buy that it's that conceptually different, especially in a dynamic language where you can dynamically instantiate and mutate classes) than it is for the papers on its implementation.
- Rochus 4y ago
  > introducing important enough new concepts What do you have in mind, apart from duck typing? > considering Smalltalk it's own ur-language, and because I agree with you that Simula at least on the surface will seem more familiar to people familiar with ALGOL-derived For ST we have to differentiate the 72 and 74 from the 76 and later versions. Starting from 76 it has inheritance, compiled methods and virtual method dispatch quite similar to (though less efficient than) Simula 67.
  - vidarh 4y ago
    > What do you have in mind, apart from duck typing? The focus on message passing and late binding combined. "Duck typing" is seriously diminishing it. You can write code that appears that way even in C++ with RTTI and inheriting from a shared root class and heavy use of virtual. But to achieve the equivalent of the combination of message passing and late binding in a language like C++ not built for it you typically end up having to build your own message dispatch machinery with no syntactic support to make it cleaner that will make your code look fundamentally un-idiomatic, and so doing so is tends to be limited to specific problems. It's this combination that makes Smalltalk-derived languages feel different. > For ST we have to differentiate the 72 and 74 from the 76 and later versions. Starting from 76 it has inheritance, compiled methods and virtual method dispatch quite similar to (though less efficient than) Simula 67. I'd argue when we say Smalltalk without qualifying it, most of us will be talking about Smalltalk-80.
    - Rochus 4y ago
      > message passing and late binding combined. "Duck typing" is seriously diminishing it Actually even ST-72 made synchronous calls, but at least with a token stream interpreted by the receiving object (thus at least a bit of "message passing"). In ST-76 and later versions "message passing" is just nomenclature used by the ST folks for something that is just ordinary method dispatch and call (if you have doubts, you can analyze the innards of the ST-80 VM yourself e.g. with these tools: https://github.com/rochus-keller/Smalltalk https://github.com/rochus-keller/Smalltalk ). The major difference is the dispatch based on signature hash (similar to e.g. Java interface method calls) instead of static offsets, which enables late binding (at the expense of performance); and since everything including ordinary integers derive from Object, all values and objects are subject to dynamic method dispatch; it's no coincidence that Smalltalk was the first language to be associated with duck typing. The unification of scalar values and references, dynamic typing, and likewise the minimal syntax where control structures are implemented by means of runtime constructs were already known from Lisp; also closures (i.e. ST blocks) were already known before they were added to ST.
      - vidarh 4y ago
        > Actually even ST-72 made synchronous calls I've not suggested it is anything but synchronous, so I don't know why you're bringing that up. It's not what we're talking about when we talk about "message passing" in this context. > In ST-76 and later versions "message passing" is just nomenclature used by the ST folks for something that is just ordinary method dispatch and call (if you have doubts, you can analyze the innards of the ST-80 VM yourself e.g. with these tools: https://github.com/rochus-keller/Smalltalk https://github.com/rochus-keller/Smalltalk ). Sure, you can implement method dispatch the same way. I've written a (partial; unfinished; very buggy) Ruby compiler that allows dynamic method redefinition with even basic C++-style vtables. The point is not the dispatch method but the ability to override them at will. > The major difference is the dispatch based on signature hash (similar to e.g. Java interface method calls) instead of static offsets, which enables late binding That late binding is an important part of it. But you don't even need to deviate from static offsets to enable that late binding (you do need to do so if you want the ability to do dynamic interface-based inheritance, but even then you can use a vtable-like approach - see e.g. Protocol Extension: A Technique for Structuring Large Extensible Software-Systems, M. Franz, 1995 - which adds dynamic inheritance at runtime to Oberon) as long as the dictionaries/vtables/whatever you look them up in are mutable.
- cratermoon 4y ago
  > prototypes instead of classes Maybe the author picked that one as being in the lineage of JavaScript?
  - vidarh 4y ago
    It is absolutely reasonable to group Self and Javascript together for that reasons, sure. I just don't think even that is sufficient reason to consider Self the "ur-language". If he'd created a separate category for prototype-base OO, Self would belong there, though.

by Rochus 4y ago

vidarh 4y ago

Ii is, because it inspired both the Smalltalk branch and the more mainstream OO languages, and hence it makes sense to consider it as a possible ur-language in that sense. Smalltalk is a branch, but it's an important enough branch introducing important enough new concepts that unlike with Self I wouldn't have an issue with people considering Smalltalk it's own ur-language, and because I agree with you that Simula at least on the surface will seem more familiar to people familiar with ALGOL-derived languages with OO mechanisms than to Smalltalk. Self, on the other hand, is less important for its concepts (ok, so it has prototypes instead of classes, but classes in Smalltalk are also objects, so I don't buy that it's that conceptually different, especially in a dynamic language where you can dynamically instantiate and mutate classes) than it is for the papers on its implementation.

Rochus 4y ago
> introducing important enough new concepts What do you have in mind, apart from duck typing? > considering Smalltalk it's own ur-language, and because I agree with you that Simula at least on the surface will seem more familiar to people familiar with ALGOL-derived For ST we have to differentiate the 72 and 74 from the 76 and later versions. Starting from 76 it has inheritance, compiled methods and virtual method dispatch quite similar to (though less efficient than) Simula 67.
- vidarh 4y ago
  > What do you have in mind, apart from duck typing? The focus on message passing and late binding combined. "Duck typing" is seriously diminishing it. You can write code that appears that way even in C++ with RTTI and inheriting from a shared root class and heavy use of virtual. But to achieve the equivalent of the combination of message passing and late binding in a language like C++ not built for it you typically end up having to build your own message dispatch machinery with no syntactic support to make it cleaner that will make your code look fundamentally un-idiomatic, and so doing so is tends to be limited to specific problems. It's this combination that makes Smalltalk-derived languages feel different. > For ST we have to differentiate the 72 and 74 from the 76 and later versions. Starting from 76 it has inheritance, compiled methods and virtual method dispatch quite similar to (though less efficient than) Simula 67. I'd argue when we say Smalltalk without qualifying it, most of us will be talking about Smalltalk-80.
  - Rochus 4y ago
    > message passing and late binding combined. "Duck typing" is seriously diminishing it Actually even ST-72 made synchronous calls, but at least with a token stream interpreted by the receiving object (thus at least a bit of "message passing"). In ST-76 and later versions "message passing" is just nomenclature used by the ST folks for something that is just ordinary method dispatch and call (if you have doubts, you can analyze the innards of the ST-80 VM yourself e.g. with these tools: https://github.com/rochus-keller/Smalltalk https://github.com/rochus-keller/Smalltalk ). The major difference is the dispatch based on signature hash (similar to e.g. Java interface method calls) instead of static offsets, which enables late binding (at the expense of performance); and since everything including ordinary integers derive from Object, all values and objects are subject to dynamic method dispatch; it's no coincidence that Smalltalk was the first language to be associated with duck typing. The unification of scalar values and references, dynamic typing, and likewise the minimal syntax where control structures are implemented by means of runtime constructs were already known from Lisp; also closures (i.e. ST blocks) were already known before they were added to ST.
    - vidarh 4y ago
      > Actually even ST-72 made synchronous calls I've not suggested it is anything but synchronous, so I don't know why you're bringing that up. It's not what we're talking about when we talk about "message passing" in this context. > In ST-76 and later versions "message passing" is just nomenclature used by the ST folks for something that is just ordinary method dispatch and call (if you have doubts, you can analyze the innards of the ST-80 VM yourself e.g. with these tools: https://github.com/rochus-keller/Smalltalk https://github.com/rochus-keller/Smalltalk ). Sure, you can implement method dispatch the same way. I've written a (partial; unfinished; very buggy) Ruby compiler that allows dynamic method redefinition with even basic C++-style vtables. The point is not the dispatch method but the ability to override them at will. > The major difference is the dispatch based on signature hash (similar to e.g. Java interface method calls) instead of static offsets, which enables late binding That late binding is an important part of it. But you don't even need to deviate from static offsets to enable that late binding (you do need to do so if you want the ability to do dynamic interface-based inheritance, but even then you can use a vtable-like approach - see e.g. Protocol Extension: A Technique for Structuring Large Extensible Software-Systems, M. Franz, 1995 - which adds dynamic inheritance at runtime to Oberon) as long as the dictionaries/vtables/whatever you look them up in are mutable.
cratermoon 4y ago
> prototypes instead of classes Maybe the author picked that one as being in the lineage of JavaScript?
- vidarh 4y ago
  It is absolutely reasonable to group Self and Javascript together for that reasons, sure. I just don't think even that is sufficient reason to consider Self the "ur-language". If he'd created a separate category for prototype-base OO, Self would belong there, though.