Refractive PPX
PPX Rewriter for generating Refractive lenses and selectors.
To enable
Install @tizoc/refractive_ppx:
npm i --save-dev @tizoc/refractive_ppx
Add this to your bsconfig.json file:
"ppx-flags": [
"@tizoc/refractive_ppx/ppx.exe"
],How to use
Add a [@refractive.derive] annotation to a type declaration (only record types are supported):
[@refractive.derive]
type t = { ... };The expansion will define two new modules:
-
Lensesif the type name ist, or<Titlecased-type-name>Lensesfor any other name. -
Selectorsif the type name ist, or<Titlecased-type-name>Selectorsfor any other name.
The Lenses module will include one lense declaration for each record field, with the same name.
The Selectors module will include one selector declaration for each record field, with the same name. The path will be the same as the name of the field, and a lense of the same name will be used.
For recursive type definitions, the [@refractive.derive] has to be added to each type declaration for which lenses and selectors should be generated.
Example
The following declaration:
module User = {
[@refractive.derive]
type t = {
id: string,
email: string,
username: string,
score: int,
};
};gets expanded to:
module User = {
type t = {
id: string,
email: string,
username: string,
score: int,
};
module Lenses = {
let id =
Refractive.Lens.make(
~get=x => x.id,
~set=(newVal, x) => {...x, id: newVal},
);
let email =
Refractive.Lens.make(
~get=x => x.email,
~set=(newVal, x) => {...x, email: newVal},
);
let username =
Refractive.Lens.make(
~get=x => x.username,
~set=(newVal, x) => {...x, username: newVal},
);
let score =
Refractive.Lens.make(
~get=x => x.score,
~set=(newVal, x) => {...x, score: newVal},
);
};
module Selectors = {
let id = Refractive.Selector.make(~lens=Lenses.id, ~path=[|"id"|]);
let email = Refractive.Selector.make(~lens=Lenses.email, ~path=[|"email"|]);
let username = Refractive.Selector.make(~lens=Lenses.username, ~path=[|"username"|]);
let score = Refractive.Selector.make(~lens=Lenses.score, ~path=[|"score"|]);
};
};For a type named t, no prefix is added to the generated modules. Otherwise, the name of the type is titlecased and used as a prefix. A type named user will generate modules named UserLenses and UserSelectors.