A syntax extension for Rust's matches! in OCaml 🐪

This library has not yet been released to opam. To install it, first

opam install ppx_matches

Users of dune can then use this PPX on their libraries and executables by adding the appropriate stanza field:

(library
 ...
 (preprocess (pps ppx_matches)))

In short:

• [%matches? pat [when cond]] expands to

  function
  | pat [when cond] -> true
  | _ -> false
  

• [%matches? pat [when cond]] matchee expands to the inlined version:

  match matchee with
  | pat [when cond] -> true
  | _ -> false