Routing/Endpoint DSL about midas

[nono]

I don't have a lot of experiences with functional programming, but the router makes me think to pattern matching:

// users.gleam
import midas

fn list() -> midas.Response {
  // TODO return a midas.Response with the list of users
}

fn get_post(user_id: String, post_id: String) -> midas.Response {
  let published = midas.QueryParam(req, "published")
  // TODO return a midas.Response with the given post

pub fn router(req: midas.Request, path: List(String)) -> midas.Response {
  let is_user_id = midas.String([midas.MinLength(14), midas.MaxLength(14)])
  let is_post_id = midas.Integer([midas.Max(999)])
  case [req.Verb, path] {
    [midas.Get, []] -> list(req, res)
    [midas.Get, [user_id, "posts", post_id]] if is_user_id(user_id) && is_post_id(post_id) -> get_post(user_id, post_id)
    _ -> midas.error404(req)
  }
}

// router.gleam
import midas
import my_app/users

pub fn router(req: midas.Request) -> midas.Response {
  case req.SplittedPath {
    ["users" | rest] -> users.router(req, rest)
    _ -> midas.error404(req)
  }
}

A limitation is that I don't know how to make post_id an Int (and not just a String to parse).

Maybe it can give you some ideas.

Update: I've read again the README, and I feel stupid to suggest what is already there. Let's just say that I prefer what is in the README to the other suggestions.

[CrowdHailer]

The pattern matching solution is nice, it's certainly the most simple.
You hit the nail on the head about the integers though. The DSL suggested here gives you more type safety but potentially not worth the overhead.

As mentioned, it can exist as an experimental API for a while because the option of a simple case statement and matching will always exist.