With PieMixin

In this thread: Trying to guess the programming language based on a single keyword and angle brackets. 🙃

44

True, but that's definitely C#

10

In Scala:

case class Fix[F[_]](unfix: F[Fix[F]])
case class Pie[T](filling: T)
def ohNo: Fix[Pie] = Fix(Pie(ohNo))

16

Type erasure sure does go brr...

3

is something which is completely unhinged out of context, and sometimes even in context.

12

I understand the syntax but i dont get the joke.

2

It's an asdf video. "I've got a pie! What flavour? Pie flavourrrr"

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Which language are we talking here? Cpp? Because typeof hasn't ever seemed useful to me in how I use cpp or how I have ever really used a language. I also remember it being criticized in java class more than 20 years ago when OOP was solely preached, even for scientific people like me.

-23

This sure looks like C#. I use typeof every once in a while when I want to check that the type of a reference is a specific type and not a parent or derived type. But yea, really not that often.

38
- It looks exactly like c++ and c# and java and probably others.
  
  9
- Yeah in C# it has quite a few uses.
  
  I'm working on a background fun project where there's a base class that is for olde style CPU emulation. Where you can derive a class from the base class and essentially design 8bit style CPUs.
  
  I have a separate class as a generic Assembler that will work with any of the created CPUs. But, to be able to do that I need to be able to get information about instructions, arguments, opcodes, registers etc from the derived class.
  
  So the assembler is instantiated with Assembler\ and then it uses typeof to instantiate the actual CPU class being used to get all the information.
  
  So, that's just an example of when you'd use something like this.
  
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  2
This is likely referring to TypeScript.

TypeScript has all of these patterns, they are used very frequently and they are necessary because TypeScript tends to be interesting from time to time since its types only exist at compile time, because it compiles to JavaScript, which is a language without types.

TypeScript also allows any as a keyword, which says "I don't know which type this is and I don't care", which still produces valid JavaScript. To get back to typed variables it is necessary to use typeof (or similar constructs like a type guard).

https://www.typescriptlang.org/docs/handbook/2/typeof-types.html

25
- But generic type syntax is a feature exclusive to Typescript while typeof is a JavaScript thing. You'd never get Pie[Pie[T]] as a result from a typeof check. (Please excuse the square brackets; seems like the markdown parser here isn't quite right and it keeps messing up the angle brackets)
  
  Also, it's typeof foo not typeof(foo) in js
  
  3
- Given the callout as a mixin, you're probably right. Other languages have them, but I've only heard something described in practice as a mixin working in Angular and Typescript. (Neither of which are my forte, so if I'm wrong, I'm wrong.)
  
  1
I'm not shy about using typeof for logging when it's appropriate. Anything braver than that and you're probably getting into reflection, which also means you're probably not writing the code the way you should.

4
- Your assumption that "using reflection means the code is wrong" seems a bit extreme, at least in .Net. Every time you interact with types, you use reflection. Xml and Json serialization/deserialization uses reflection, and also Entity Framework. If you use mocking in test you are using reflection.
  
  We have an excel export functionality on our sites that uses reflection because we can write 1 function and export any types we want, thanks to reflection.
  
  16
- Hm, I'm currently working on a project with a ton of runtime-configurable plug-ins and dependencies between them. All of that is held together with a copious amount of black QMetaObject magic. I had the same thought about it, but I'm not sure how you'd get similar functionality without reflection and not making it even more convoluted and fragile...
  
  5
It's very useful in zig's comptime.

2
TypeScript?

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