crypto.hash_string?

[Blue Slime]

Hi there!
A hash_string function would be very nice to have, instead of being required to use BitString.

Let's say we want to hash a string composed of other strings without compromising performance (a very common operation with crypto-releated stuff).
With Elixir, we could do something like this:

  def hash_block(block) do
    :crypto.hash(:sha256, [block.id, block.data, Integer.to_string(block.timestamp])
  end

With Gleam this is a little bit more complicated, since crypto.hash method requires a BitString. The code above would probably look like something like this:

pub fn hash_block(block: Block) {
  bit_builder.from_string(block.id)
  |> bit_builder.append_string(block.data)
  |> bit_builder.append_string(int.to_string(block.timestamp))
  |> bit_builder.to_bit_string
  |> crypto.hash(crypto.Sha256, _)
  ...
}

This is obviously too much.

Instead, there could be a function that takes String as an input. The code above would look something like this:

pub fn hash_block(block: Block) {
  string_builder.from_strings([
    block.id,
    block.data,
    int.to_string(block.timestamp)
  ])
  |> string_builder.to_string
  |> crypto.hash_string(crypto.Sha256, _)
  ...
}

Much better!

NOTE: I tried adding the function and it works just fine, passes all tests + new ones I added for this purpose specifically. I don't think it will cause any problems since Gleam already uses UTF-8 binaries under the hood. If it sounds good to you guys I can create the pull request with everything.

[Louis Pilfold]

Could be handy, though in this specific case I would use a bit string literal.

pub fn hash_block(block: Block) {
  crypto.hash(
    crypto.Sha256,
    <<
      block.id:utf8,
      block.data:utf8,
      int.to_string(block.timestamp):utf8,
    >>
  )
}

[Louis Pilfold]

Closing due to lack of activity.