feat(stdlib): Add String.lastIndexOf

[spotandjake]

This pr adds String.lastIndexOf, it works the same as indexOf but instead of returning the first occurance of the search it returns the last.

[ospencer]

I think what might be a bit better here is reusing the code from indexOf. The only difference between the two would be the break line in the loop.

You can turn indexOf into a helper function that takes an additional argument, maybe called findFirst, and then that if becomes

      if (Memory.compare(ptr, pptr, psize) == 0n) {
        result = idx
        if (findFirst) break
      }

And then you can call the helper for both functions:

export let indexOf = (search, string) => {
  indexOf(search, string, true)
}
export let lastIndexOf = (search, string) => {
  indexOf(search, string, false)
}

[ospencer]

I left some suggestions here—I switched up the logic a bit to avoid a Memory.compare when we're not at the start of a valid codepoint.

[ospencer]

Great work!

[ospencer]

Looks like you need to regenerate the Graindocs.

[phated]

I'm holding off my review until #1389 lands because this PR contains a bunch of formatting that shouldn't be included in the PR

[spotandjake]

Looks like you need to regenerate the Graindocs.

GrainDoc Seems To Be Up To Date

[phated]

Really cool! I like that you are diving into the low-level Grain stuff @spotandjake 🎉

[spotandjake]

Really cool! I like that you are diving into the low-level Grain stuff @spotandjake 🎉

Thank you, after working on my linker I have needed to work with a lot more low level grain stuff and realized it is actually quite friendly and easy to work with.