AuthorPetter A. Urkedal
LicenseLGPL-3 with OCaml linking exception
Issue Trackerhttps://github.com/paurkedal/ppx_compose/issues
&jbuilder>= 1.0+beta7
Availableocaml-version >= "4.02.3"
PublishedDec 17, 2017
Source [http] https://github.com/paurkedal/ppx_compose/releases/download/v0.0.4/ppx_compose-0.0.4.tbz
StatisticsInstalled 5 times last month.

Inlined Function Composition

ppx_compose is a simple syntax extension which rewrites code containing function compositions into composition-free code, effectively inlining the composition operators. The following two operators are supported

let (%) g f x = g (f x)
let (%>) f g x = g (f x)

Corresponding definitions are not provided, so partial applications of (%) and (%>) will be undefined unless you provide the definitions.

The following rewrites are done:

  • A composition occurring to the left of an application is reduced by applying each term of the composition from right to left to the argument, ignoring associative variations.

  • A composition which is not the left side of an application is first turned into one by η-expansion, then the above rule applies.

  • Any partially applied composition operators are passed though unchanged.


h % g % f ==> (fun x -> h (f (g x)))
h % (g % f) ==> (fun x -> h (f (g x)))
(g % f) (h % h) ==> g (f (fun x -> h (h x)))
No package is dependent