package ppx_compose
Install
Dune Dependency
Authors
Maintainers
Sources
sha256=414f72a7659f2e85cf87ddcbf9981f793aa78ea3a607c35a8237e5ee305811b3
sha512=d69bfab88b4d4949bc5189724f954f33e1c2fa36d9fcf1dded351d379c241345533bf12bf493b26acbbcb6bd726674c22c934f037ec0b2820b6a5f99cfbc9ba3
Description
ppx_compose
is a simple syntax extension which rewrites code containing
function compositions into compositionfree 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 ηexpansion, then the above rule applies.

Any partially applied composition operators are passed though unchanged.
E.g.
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)))
Published: 12 Oct 2021
README
README.md
ppx_compose
 Inlined Function Composition
ppx_compose
is a simple syntax extension which rewrites code containing function compositions into compositionfree 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 ηexpansion, then the above rule applies.
Any partially applied composition operators are passed though unchanged.
E.g.
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)))
Is It Needed?
Recent flambdaenabled compilers can inline the following alternative definitions of the composition operators [1]:
let (%) g f = (); fun x > g (f x)
let (%>) f g = (); fun x > g (f x)
so this syntax extension will likely be retired at some point.