Proposing new syntax for zero-cost unwrapping options/results

I’m usually a fan of map and flatMap when using Option, but removing the runtime hit for calling functions is very appealing.

Here’s I function I found in one of my projects.

let query =
  ctx.url.search
  ->String.replace("?", "")
  ->String.split("&")
  ->Array.map(String.split(_, "="))
  ->Array.find(x => x[0] == Some("query"))
  ->Option.flatMap(Array.at(_, 1))
  ->Option.map(decodeURIComponent)
  ->Option.getOr("")

Which I think would look like this:

let query = {
  let? Some(query) = ctx.url.search
    ->String.replace("?", "")
    ->String.split("&")
    ->Array.map(String.split(_, "="))
    ->Array.find(x => x[0] == Some("query"))

  let? Some(uriComponent) = query->Array.at(1)
  let? Some(decoded) = decodeUriComponent(uriComponent)

  decoded->Option.getOr("")
}

I’m not a fan of the extra names for things and I would probably just use Some(x) all the time. This would remove any ReScript specific functions from the output (excluding the getOr), which would be really nice.

Having a way to easily bail to a fallback value like Option.getOr would be nice to have. I would have to have that be a switch right now to get rid of that function.

I’m not sure anything I am doing get seriously impacted enough by the performance for me to move away from the pipe and pointfree style I like, but it is nice to have this available.