get_in ppx

An exploration of the "safe call operators" pull-request, implemented as a ppx.

Installation

npm i get_in_ppx

bsconfig.json

"ppx-flags": ["get_in_ppx/ppx"]

Operators

This ppx includes two operators, that are valid within the [%get_in ] form.

• #?? is to be used when both sides are optional. E.g. the object on the left is optional, and the attribute you're getting out is also optional. e.g. option({. "attr": option(int)})
• #? is to be used when only the object is optional, but the attribute you're getting out is not. e.g. option({. "attr": int})

Usage

/* some data with optional attributes in javascript objects (e.g. from graphql) */
let one = Some({"two": Some({"three": 4})});

let x: option(int) = [%get_in one#??two#?three];