> Gleam doesn’t have access to most of the Erlang / Elixir ecosystem out of the box.

Gleam has access to the entire ecosystem out of the box, because all languages on the BEAM interoperate with one another. For example, here's a function inside the module for gleam_otp's static supervisor:

    @external(erlang, "supervisor", "start_link")
    fn erlang_start_link(
      module: Atom,
      args: #(ErlangStartFlags, List(ErlangChildSpec)),
    ) -> Result(Pid, Dynamic)

As another example, I chose a package[0] at random that implements bindings to the Elixir package blake2[1].

    @external(erlang, "Elixir.Blake2", "hash2b")
    pub fn hash2b(message m: BitArray, output_size output_size: Int) -> BitArray

    @external(erlang, "Elixir.Blake2", "hash2b")
    pub fn hash2b_secret(
      message m: BitArray,
      output_size output_size: Int,
      secret_key secret_key: BitArray,
    ) -> BitArray

It's ok if you don't vibe with Gleam – no ad-hoc poly and no macros are usually dealbreakers for certain types of developer – but it's wrong to say you can't lean on the wider BEAM ecosystem!

[0]: https://github.com/sisou/nimiq_gleam/blob/main/gblake2/src/g...

[1]: https://hex.pm/packages/blake2