README.md

Pipeline.sjs

This library provides pipelining syntax to achieve naturally expressive functional composition with a little help from Sweet.js. It can be installed in whichever way you prefer, but I recommend NPM.

The motivation was to make reading functional composition more natural by writing left to right rather than inside out. My original choice of operator was |> to match a similar operator in Elixir, but due to some limitations of Sweet.js this wasn't possible. The examples below show usage with the default >> operator.

Usage examples

var foo = function(){},
    bar = function(){},
    baz = function(){};

// Basic composition
123 >> foo; // Compiles to foo(123);

// Functional composition
foo >> bar; // Compiles to bar(foo);

// Chained composition
123 >> foo >> bar; // Compiles to bar(foo(123));

// Multi-line composition
123
>> foo
>> bar
>> baz; // Compiles to baz(bar(foo(123)));

// Partially applied composition
foo >> bar >> baz(123); // Compiles to baz(123, bar(foo));

// Partially applied with many arguments
foo >> bar(1, 2, 3) >> baz; // Compiles to baz(bar(1, 2, 3, foo));

// Partially applied with backreference
foo >> bar >> baz(&, 123); // Compiles to baz(bar(foo), 123);

Transpiling

Whenever you use this or any other Sweet.js macro, you need to run it through sjs.

$ npm install pipeline.sjs sweet.js
$ node_modules/.bin/sjs -m pipeline.sjs/macro mysweetfile.sjs

Custom operators

You can change the operators used in this macro by running the build script with your own choice.

$ MACRO_OP='>>' MACRO_REF='&' npm run build

Contributing

I accept contributions to the source via Pull Request, but passing unit tests must be included before it will be considered for merge.

$ npm run build
$ npm test

If you have Vagrant installed, you can build the dev environment to assist development. The repository will be mounted in /srv.

$ curl -O https://raw.github.com/adlawson/vagrantfiles/master/nodejs/Vagrantfile
$ vagrant up
$ vagrant ssh

Welcome to Ubuntu 12.04 LTS (GNU/Linux 3.2.0-23-generic x86_64)
$ cd /srv

License

The content of this library is released under the MIT License by Andrew Lawson.
You can find a copy of this license in LICENSE or at http://www.opensource.org/licenses/mit.