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ExWeb3 / ex_keccak

Elixir library for computing Keccak SHA3-256 hashes using a NIF built tiny-keccak Rust crate.
Apache License 2.0
25 stars 20 forks source link

Add throwing variant `ExKeccak.hash_256!/1` #4

Closed tsutsu closed 3 years ago

tzumby commented 3 years ago

Hey @tsutsu, thanks for contributing! What's the benefit of delegating to the Impl module here ?

tsutsu commented 3 years ago

This is a common pattern in NIFs. The Erlang-side NIF module has to expose only the public functions that exist in the NIF itself. But the API surface of the NIF itself should be kept to a minimum, because it's harder to write/prove trustworthy code in a native language. So the usual solution is to create an Impl module into which the NIF is loaded, which simply mirrors the minimal API of the NIF itself; and then to hide this impl module behind a wrapper module, that uses Erlang glue-code (rather than native glue-code) to safely decorate the API into a more usable form.

If you're asking about defdelegate — it's strictly equivalent to just writing def foo(...), do: Module.foo(...). It just expresses intent more explicitly. (It also automatically defines functions for all arities the remote function is defined with, but that's not relevant here.)

tzumby commented 3 years ago

Thanks @tsutsu! I'll approve and merge this, do you mind bumping the version to 0.1.3 and updating the Changelog ?

tsutsu commented 3 years ago

Sure, no problem