Currying and partial application in PHP 7

Helpers are provided to curry and partially apply arguments to closures.

Motivation

1. Functional patterns are helpful and interesting.
2. PHP 7 offers new features that make currying and partial application easier.
3. While some existing PHP libraries exist that claim to address partial application and/or currying are just doing partial application and aren't using the PHP 7 hotness.

Helpers

curry(Closure $closure)

Curries the given closure, left-precedent arguments.

curry_right(Closure $closure)

Curries the given closure, right-precedent arguments.

bind(Closure $closure, ...$args)

Partially applies arguments to the given closure, left-precedent arguments.

bind_right(Closure $closure, ...$args)

Partially applies arguments to the given closure, right-precedent arguments.

@todo

• Some examples in this readme pls
• bind_args with placeholders
• See https://javascript.info/currying-partials for more