https://github.com/rizo/optimist

Everything is going to be Ok.
https://github.com/rizo/optimist

Last synced: about 1 month ago
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Everything is going to be Ok.

• Host: GitHub
• URL: https://github.com/rizo/optimist
• Owner: rizo
• License: mit
• Created: 2024-03-25T17:41:58.000Z (10 months ago)
• Default Branch: main
• Last Pushed: 2024-04-22T16:44:10.000Z (9 months ago)
• Last Synced: 2024-04-22T18:12:05.427Z (9 months ago)
• Language: OCaml
• Size: 13.7 KB
• Stars: 6
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Optimist

An OCaml ppx that helps you write happier code.

## Supported rewrite rules

```ocaml

let%ok ... = ... in ...

let%some ... = ... in ...

let%await ... = ... in ...

let%await.ok ... = ... in ...

let%await.some ... = ... in ...

match%ok ... with ...

match%some ... with ...

match%await ... with ...

match%await.ok ... with ...

match%await.some ... with ...

if%ok ... then ... else ...

if%some ... then ... else ...

if%await ... then ... else ...

if%await.ok ... then ... else ...

if%await.some ... then ... else ...

```

## Lwt backtrace propagation

The main difference between using `(let*)` and `let%await` (or the standard

`let%lwt`) is that, with the ppx version, the async exceptions will correctly

propagate their backtraces.

The following example demonstrates the fully expanded code for `%await.ok`

```ocaml

let%await.ok p = m in e

(* Is desugared into... *)

let module Reraise = struct

  external reraise : exn -> 'a = "%reraise"

end

in

Lwt.backtrace_bind

  (fun exn -> try Reraise.reraise exn with exn -> exn)

  m

  (fun p_result ->

    match with

    | Ok p -> e

    | Error err -> Lwt.return (Error err))

```