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Alain
Alain

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Using `let.opt` in Rescript with latest Reason/OCaml

#rescript #reason #melange #ocaml

This is your Reason (let.opt) definition.

let (let.opt) = (x, f) => switch (x) { | None => None | Some(x) => f(x) }; let (and.opt) = (a, b) => switch (a, b) { | (Some(a), Some(b)) => Some((a, b)) | _ => None }; let z = (a,b)=> { let.opt a = a and.opt b = b; Some(a + b); };
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This is your Rescript file on ocaml@4.12.0:

//Demo.res let a = Some(10); let b = Some(3); Js.log2("using ocaml 4.12 compiled reasonml let.opt in Rescript", Opts.z(a,b));
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Here is a gist.

Here is a project you can run:

GitHub logo idkjs / letop-rescript

using (let.opt) style in rescript

Resources: https://github.com/ocaml/ocaml/pull/1947
Melange:https://github.com/melange-re/melange
Rescript:https://rescript-lang.org/
Discord:https://discord.gg/KAJBzYaf

Top comments (1)

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danielo515 profile image
Daniel Rodríguez Rivero •

Do you mean explaining how is this applied ? And expects a and b, and returns a tuple, which I don’t see used in z nor in the first letop. Can you expand further ?