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Comment by michaelmior | Hacker News Reader

I guess I haven't read enough Rust code to come across this patterns, but I don't think I particularly like it. Perhaps I would get used to it though :)

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It works the same way in Haskell, eg

  main = do
    let x = 2
    let x = "foo"
    y <- pure 3
    y <- pure "bar"
    putStrLn $ x ++ y

which is really the same as

  main =
    let x = 2
    in let x = "foo"
       in pure 3 >>= \y ->
                       pure "bar" >>= \y ->
                                        putStrLn $ x ++ y

So it works pretty naturally where each assignment is kind of like a new scope. If the type system is good, I don't think it really causes issues.

Haskell has got to be by far the least readable language in the world, all of that is incomprehensible

I'm not sure what you find incomprehensible about the first example. The syntax is pretty standard. The only exotic thing is `$`, which is basically just like putting brackets around the rest of the line. Here's the first example roughly translated to Python:

  def main():
      x = 2
      [x] = ["foo"]
      y = 3
      [y] = ["bar"]
      print(x + y)

Seems about the same level of comprehensibility to me. Is there anything in particular you find difficult to understand?

The second example is expanded out and not how a person would normally write it, but if you're familiar with the basic concepts it's using, it shows why it works very clearly; think of it like assembler.

Er, actually

  x = 2
  x = "foo"
  [y] = [3]
  [y] = ["bar"]

Sorry, I didn't re-read the code before translating.

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