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Thanks! Let me know if you have any questions - I've long wanted to write something "system-level" in Elixir.

by qdotme 5mo ago

kajman 5mo ago
I've bounced off learning (hobby-tier) Elixir a few times now. For me, the gradual type system combined with the functional flow has been hardest to wrap my head around when it comes to solving problems. I'm curious about how you approached handling a lower-level protocol in Elixir. When you began implementation, did you start thinking at the level of packets as structs, or maybe first as just maps that flowed through functions?
- qdotme 5mo ago
  Pretty much functions with pattern matching all-across, passing around bitstrings, relatively dynamically typed. Grab a buffer, make sure it's at least as long as BHS, shove into BHS, ok, make sure it's at least as long as what the BHS requires... Pattern matching is the hidden power of Elixir that's probably the hardest to get fluent with, it's IMHO harder than Rust's equivalent (because of gradual typing!) - but when it works it blows Pythons' match syntax way, way out. # Example: Login Request with immediate = 0x03 | 0x40 = 0x43. defp parse_lengths(<< _reserved::1, _i_bit::1, opcode::6, _flags::8, _specific1::16, ahs_length::8, data_length::24, _rest::binary >>) do {:ok, opcode, ahs_length * 4, data_length} end defp parse_lengths(_), do: {:error, :invalid_bhs}
  - kajman 5mo ago
    That is an interesting example, thank you for the insight. It is amazing how simple logic is when you're able to front-load pre-reqs into a pattern match, but the idea of defining a function multiple times still feels "wrong" to me for now. Overall, it's really cool to see Elixir applied like this. Congrats on the launch!
    - qdotme 5mo ago
      Thanks! It's truly a special concept somewhere between an overload and a pattern match. And unexpectedly performant - most of these are just type coercions, that resolve compile-time.

Thanks! Let me know if you have any questions - I've long wanted to write something "system-level" in Elixir.

by qdotme 5mo ago

Thanks! Let me know if you have any questions - I've long wanted to write something "system-level" in Elixir.

I've bounced off learning (hobby-tier) Elixir a few times now. For me, the gradual type system combined with the functional flow has been hardest to wrap my head around when it comes to solving problems. I'm curious about how you approached handling a lower-level protocol in Elixir. When you began implementation, did you start thinking at the level of packets as structs, or maybe first as just maps that flowed through functions?

qdotme 5mo ago
Pretty much functions with pattern matching all-across, passing around bitstrings, relatively dynamically typed. Grab a buffer, make sure it's at least as long as BHS, shove into BHS, ok, make sure it's at least as long as what the BHS requires... Pattern matching is the hidden power of Elixir that's probably the hardest to get fluent with, it's IMHO harder than Rust's equivalent (because of gradual typing!) - but when it works it blows Pythons' match syntax way, way out. # Example: Login Request with immediate = 0x03 | 0x40 = 0x43. defp parse_lengths(<< _reserved::1, _i_bit::1, opcode::6, _flags::8, _specific1::16, ahs_length::8, data_length::24, _rest::binary >>) do {:ok, opcode, ahs_length * 4, data_length} end defp parse_lengths(_), do: {:error, :invalid_bhs}
- kajman 5mo ago
  That is an interesting example, thank you for the insight. It is amazing how simple logic is when you're able to front-load pre-reqs into a pattern match, but the idea of defining a function multiple times still feels "wrong" to me for now. Overall, it's really cool to see Elixir applied like this. Congrats on the launch!
  - qdotme 5mo ago
    Thanks! It's truly a special concept somewhere between an overload and a pattern match. And unexpectedly performant - most of these are just type coercions, that resolve compile-time.