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by devmunchies 1937 days ago
Does gleam let me destructure a list so that I can bind the head and body each to a variable?

e.g. in f#

    let splitHeadAndTail = function
      | h :: [] -> printfn "got head and EMPTY tail"
      | h :: t -> printfn "got head and tail"
      | [] -> printfn "got empty list"
The example in their docs does a 1:1 map and doesn't show if you can bind the whole tail[1]

[1]: https://gleam.run/book/tour/case-expressions.html#destructur...
2 comments
derefr 1937 days ago
Yes; see https://hexdocs.pm/gleam_stdlib/gleam/list/. The syntax is [head, ..tail]

It'd be kind of silly to create a greenfield BEAM language that doesn't expose one of the most fundamental operations you can do in BEAM bytecode, and that every list-processing function ultimately relies upon :)

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devmunchies 1937 days ago
> It'd be kind of silly to have a BEAM language that doesn't expose one of the most primitive operations you can do in the BEAM, that every list-processing function ultimately relies upon :)

Agree, which is why i was confused it wasn't in the tour I linked to in the Lists or Destructuring sections

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centimeter 1936 days ago
Why not just use Haskell? You don't get OTP/Beam, but the GHC runtime provides almost all the same functionality (plus a lot more), to the point where the Cloud Haskell library is basically a full clone of Erlang's actor functionality.
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nine_k 1936 days ago
Does it provide all of the OTP? Can you write in the "let it fail" style and be certain that the failing parts will be restarted, etc?

Also, BEAM is somehow more battle-tested.

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