Project Ramda

A practical functional library for Javascript programmers.

Goals

Using this library should feel as much like using Javascript as possible. Of course it's functional Javascript, but we're not introducting lambda expressions in strings, we're not borrowing consed lists, we're not porting over all of the Clojure functions.

Our basic data structures will be normal Javascript objects, and our usual collections will be Javascript arrays. We will not try to reach the point where all the functions have only zero, one, or two arguments. We will certainly try to keep some of the normal features of Javascript that seem to be unusual in functional languages, including variable length function signatures and functions as objects with properties.

Functional programming is in good part about immutable objects and side-effect free functions. We will stick to that as much as feasible, but will not be dogmatic about it.

As much as we can, we would like the implementation to be both clean and elegant. But the API is king: we will sacrifice a great deal of implementation elegance for even a slightly cleaner API.

Unlike the developers of that silly-named Eweda project, though, this one will focus also on performance, striving for a reliable and quick implementation over any notions of functional purity.

Installation

To use with node:

npm install ramda

Then in the console:

var ramda = require('ramda')

To use directly in the browser:

 <script src="path/to/yourCopyOf/ramda.js"></script>

or the minified version:

 <script src="path/to/yourCopyOf/ramda.min.js"></script>

These script tags add the variable ramda on the browser's global scope.

Documentation

Please review the annotated source code documentation (generated by Docco). So far, that's the only documentation available.

The Name

Ok, so we like sheep. That's all. It's a short name, not already taken. It could as easily have been eweda, but then we would be forced to say eweda lamb!, and no one wants that. For non-English speakers, lambs are baby sheep, ewes are female sheep, and rams are male sheep. So perhaps ramda is a grown-up lambda... but probably not.

Structure

Automatic Currying

The functions included should automatically allow for partial application without an explicit call to lPartial. Many of these operate on lists. A single list parameter should probably come last, which might conflict with the design of other libraries that have strong functional components (I'm looking at you Underscore!)

The idea is that, if foldl has this signature:

var foldl = function(fn, accum, arr) { /* ... */}

and we have this simple function:

var add = function(a, b) {return a + b;};

then, instead of having to manually call lPartial like this:

 var sum = lPartial(foldl, add, 0);
 var total = sum([1, 2, 3, 4]);

with ramda, we can just do this:

 var sum = foldl(add, 0);
 var total = sum([1, 2, 3, 4]);

So What's With Eweda?

The eweda library was written by the developers of this library, with similar goals. But that one strove more for implementation elegance than for practical capabilities. Ramda is all about giving users real-world tools. Eweda can be seen more as an academic excercise, mostly proving out what does and doesn't work, and doing so as elegantly as possible.

Acknowledgements

Thanks to J. C. Phillipps for the Ramda logo. Ramda logo artwork © 2014 J. C. Phillipps. Licensed Creative Commons CC BY-NC-SA 3.0.