Programmer Humor @lemmy.ml lawrence @lemmy.world 9mo ago

Ok, at some point we made a big mistake.

Hacker News post about this: https://news.ycombinator.com/item?id=39309783 (source available)

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I've written some magic templates that I assume are not easy to read by those who don't know.

But this is seemingly unmaintainable... terrifying... and kind of neat.
This doesn't actually read as serious TypeScript, moreso as someone trying to showcase unhinged code.

I'd be happy to be proven wrong with a link to the source code so that I can look the beast in the eye.
- Take a look at some typescript libraries and frameworks and you will see stuff like this. Completely unreadable mess.
  
  I have seen image recognition or text RPGs with type script types, but const ok:true = true as Grid< 4, 9, 2 Wtf
  
  Styled Components' type system is one of the most impressive and most fucked up things I've ever had to dive into.
  
  For example?
After 5 minutes of staring at it: Its typesystem sudoku. Each row and each col in the grid must add up to 15 (T<>), bit each number in the grid must be different (Df<>).

Grid will only be a type alias for the value true (google "Dependent types") only if all Type Parameters (wich are values) hold up to the Sudoku conditions).

The file would not compile with "true as Grid" when grid type-aliases to false.

Fun to understand.

EDIT: too late
I like to think I can usually look at code in languages I don't know and still get the gist of what it does but I am drawing a complete blank. Is this even slightly legible to anyone and if yes please explain
- TL;DR: Grid simplifies to true, if and only if it is a 3x3 magic square.
  
  full explanation
  
  Fifteen is an array of length 15
  
  T checks if an array of length A+B+C is equivalent to an array of length 15, thus checking if A+B+C is equal to 15
  
  And is simplifies to X if A is true, else it simplifies to false
  
  Df checks if A and B are Diffrent , simplifying to X if they are
  
  Grid first checks if every row, column and diagonal is equal to 15, then checks if every item is unique.
- Yea, i was really trying to understand… and then I was like yeah fuck this and regex too.
  
  Gotta learn regex... C++ not so much 😹
  
  Fear not, template abuse is not a necessary practice
  
  Edit: wait what is this I thought it was c++ at first. Java? C#? Has an extends keyword
Why tf
I think I can pinpoint the exact date things went sideways. It was a dark day on Monday, October 1, 2012.
Yeah, and apparently type checking/inference is trivial, says the "CTO" of Xitter. /s
I'm really trying to figure out what this is used for and why it was done this way.

I'm not having much success
- Looks like something that checks that the rows in a grid att up to 15. Why? IDK, a game?
This seems like a generic type of problem that could happen to anyone. Hopefully we can learn from this and avoid appending it to our already large grid of problems.
- I see what you did there
My soul hurts
I don't want to look at this anymore
If TypeScript didn’t have terrible type-level ergonomics, this wouldn’t look so bad—even if this toy example is largely just a brain exercise
That's why macro_rules!
- This is not rust :D Nothing will save typescript
Too much focus on compile time.

31 comments