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He who takes his examples of generics from C++ and Java has a huge blind spot. The FP crowd came up with simple and useable generics (Hindley-Milner type infer

He who takes his examples of generics from C++ and Java has a huge blind spot. The FP crowd came up with simple and useable generics (Hindley-Milner type inference) in 1982. It's like Go's creators haven't even read Pierce's Types and Programming languages. This is inexcusable. Even more so from Rob Pike and Ken Thomson —you'd expect better from such big shots.

AnimalMuppet 11y ago
It's like you assume that, since they didn't do it your way, they're either stupid, ignorant, or malicious - which I also find to be pretty inexcusable.
- aninhumer 11y ago
  I'd like to give them the benefit of the doubt, but even within their stated goal of "simplicity", some of their design choices still seem ignorant of PL theory. The obvious one being including a null value, which is widely recognised to be a terrible idea with pretty much no redeeming qualities. Another subtler example is the use of multiple return values for error handling, rather than some kind of sum type. It just suggests the designer doesn't have any experience working with ADTs. (Not that I'm suggesting Go should have used full blown ADTs, just that they change the way you think about data.)
  - AnimalMuppet 11y ago
    Simplicity is, I think, a secondary goal. A big part of the motivation for creating Go was 45 minute C++ compile times. A major reason for the emphasis on simplicity is to keep the compiler fast, even on huge codebases. So: How much would adding sum types slow down the compiler? I don't know. How fast does Go compile compared to Haskell? (Is that a fair comparison?)
    - aninhumer 11y ago
      I'm a little dubious of the speed advantage to be honest. Sure compile time is important, and C++ is pretty bad on this front, but you don't need to try that hard to do better. And no, I don't think sum types would slow the compiler down much, especially if they were limited to a special case for error handling (which seems more in line with the rest of Go).
  - sacado2 11y ago
    Sum types don't fit well with zero values. What is the zero value of an `(int|string)` union type ?
    - aninhumer 11y ago
      Well I don't think zero values are a very good idea to start with (if you want a default value, make it explicit), but if one insists on having them, they can just use the first case. So for your example it would be int 0.
- loup-vaillant 11y ago
  Well… I have seen generics that (i) don't blow up the compile times like C++ templates do, (ii) are very simple to use, and (iii) are relatively simple to implement. (I'm thinking of Hindley-Milner type inference and system F.) So when some famous guys state they avoided generics for simplicity's sake, yeah, I tend to assume they missed it. And it's not hard to miss either. When you google "generics", you tend to stumble upon Java, C#, and maybe C++. The FP crowd talks about "parametric polymorphism". Plus, if you already know Java, C# and C++, 3 mainstream examples of generics, fetching a fourth example looks like a waste of time. I bet they expected "parametric polymorphism" (ML, Haskell…) to be just as complex as "generics" (C++, Java, C#). On the other hand, when you study PL theory, you learn very quickly about Hindley-Milner type inference and System-F. Apparently they haven't. Seriously, one does not simply make a language for the masses without some PL theory.
  - AnimalMuppet 11y ago
    > On the other hand, when you study PL theory, you learn very quickly about Hindley-Milner type inference and System-F. Apparently they haven't. Again you assume that, since they didn't include it, they must not have known about it. You keep claiming that. Given the breadth of these guys' knowledge (it's not just Java, C#, and C++, not by a long shot), I really struggle to see any justification for you assuming that. I know you think that system F is all that and a bag of chips, but it is not the only reasonable way to design a language! Assuming that they did it wrong because they didn't do it the way you think is right... that's a bit much. But I'll ask you the same question I asked aninhumer: How fast does Go compile compared to Haskell? And, is that a fair comparison? If not, why not?
    - pjmlp 11y ago
      > How fast does Go compile compared to Haskell? And, is that a fair comparison? If not, why not? For this to be a fair comparison, you need to compare a Go LLVM compiler against an Haskell LLVM compiler, as possible example. For this to be viable comparison one needs to compare similar toolchains.
    - loup-vaillant 11y ago

AnimalMuppet 11y ago

It's like you assume that, since they didn't do it your way, they're either stupid, ignorant, or malicious - which I also find to be pretty inexcusable.

aninhumer 11y ago
I'd like to give them the benefit of the doubt, but even within their stated goal of "simplicity", some of their design choices still seem ignorant of PL theory. The obvious one being including a null value, which is widely recognised to be a terrible idea with pretty much no redeeming qualities. Another subtler example is the use of multiple return values for error handling, rather than some kind of sum type. It just suggests the designer doesn't have any experience working with ADTs. (Not that I'm suggesting Go should have used full blown ADTs, just that they change the way you think about data.)
- AnimalMuppet 11y ago
  Simplicity is, I think, a secondary goal. A big part of the motivation for creating Go was 45 minute C++ compile times. A major reason for the emphasis on simplicity is to keep the compiler fast, even on huge codebases. So: How much would adding sum types slow down the compiler? I don't know. How fast does Go compile compared to Haskell? (Is that a fair comparison?)
  - aninhumer 11y ago
    I'm a little dubious of the speed advantage to be honest. Sure compile time is important, and C++ is pretty bad on this front, but you don't need to try that hard to do better. And no, I don't think sum types would slow the compiler down much, especially if they were limited to a special case for error handling (which seems more in line with the rest of Go).
- sacado2 11y ago
  Sum types don't fit well with zero values. What is the zero value of an `(int|string)` union type ?
  - aninhumer 11y ago
    Well I don't think zero values are a very good idea to start with (if you want a default value, make it explicit), but if one insists on having them, they can just use the first case. So for your example it would be int 0.
loup-vaillant 11y ago
Well… I have seen generics that (i) don't blow up the compile times like C++ templates do, (ii) are very simple to use, and (iii) are relatively simple to implement. (I'm thinking of Hindley-Milner type inference and system F.) So when some famous guys state they avoided generics for simplicity's sake, yeah, I tend to assume they missed it. And it's not hard to miss either. When you google "generics", you tend to stumble upon Java, C#, and maybe C++. The FP crowd talks about "parametric polymorphism". Plus, if you already know Java, C# and C++, 3 mainstream examples of generics, fetching a fourth example looks like a waste of time. I bet they expected "parametric polymorphism" (ML, Haskell…) to be just as complex as "generics" (C++, Java, C#). On the other hand, when you study PL theory, you learn very quickly about Hindley-Milner type inference and System-F. Apparently they haven't. Seriously, one does not simply make a language for the masses without some PL theory.
- AnimalMuppet 11y ago
  > On the other hand, when you study PL theory, you learn very quickly about Hindley-Milner type inference and System-F. Apparently they haven't. Again you assume that, since they didn't include it, they must not have known about it. You keep claiming that. Given the breadth of these guys' knowledge (it's not just Java, C#, and C++, not by a long shot), I really struggle to see any justification for you assuming that. I know you think that system F is all that and a bag of chips, but it is not the only reasonable way to design a language! Assuming that they did it wrong because they didn't do it the way you think is right... that's a bit much. But I'll ask you the same question I asked aninhumer: How fast does Go compile compared to Haskell? And, is that a fair comparison? If not, why not?
  - pjmlp 11y ago
    > How fast does Go compile compared to Haskell? And, is that a fair comparison? If not, why not? For this to be a fair comparison, you need to compare a Go LLVM compiler against an Haskell LLVM compiler, as possible example. For this to be viable comparison one needs to compare similar toolchains.
  - loup-vaillant 11y ago