akh

Akh

Javascript Monad and Monad Transformer Collection

Overview

Collection of simple monad and monad transformers that implement Fantasy Land's interfaces.

Monad Transformers

• IdentityT - akh::trans::identity - Transforms a monad to itself. (Monad, Functor, Applicative Functor)
• StateT - akh::trans::state - State transformer. (Monad, Monoid, Functor, Applicative Functor)
• ListT - akh::trans::list - List transformer. (Monad, Monoid, Functor, Applicative Functor)
• ContT - akh::trans::cont - Continuation transformer. (Monad, Functor, Applicative Functor)
• DContT - akh::trans::dcont - Delimited continuation transformer. (Monad, Functor, Applicative Functor)
• EitherT - akh::trans::either - Either transformer. (Monad, Monoid, Functor, Applicative Functor)
• ErrorT - akh::trans::error - Error transformer. (Monad, Monoid, Functor, Applicative Functor)
• UniqueT - akh::unique Add unique int to monad (Monad, Monoid, Functor, Applicative Functor)

Monads

• Identity - akh::identity - Identity computation. (Monad, Functor, Applicative Functor)
• State - akh::state - Stateful computation. (Monad, Functor, Applicative Functor)
• List - akh::list - List computation. (Monad, Monoid, Functor, Applicative Functor)
• Cont - akh::cont - Continuation computation. (Monad, Functor, Applicative Functor)
• DCont - akh::dcont - Delimited continuation computation. (Monad, Functor, Applicative Functor)
• EitherT - akh::either - Either computation. (Monad, Functor, Applicative Functor)
• ErrorT - akh::error - Error computation. (Monad, Functor, Applicative Functor)
• Trampoline - akh::trampoline Trampolined computation (Monad, Functor, Applicative Functor)
• Unique - akh::unique Get Unique int (Monad, Monoid, Functor, Applicative Functor)

Install

Node

Node files live in dist_node

$ npm install akh

var List = require('akh').list;

var c =
    List.of(1)
        .chain(function(x) {
            return List.of([x, x + 1])
        })
        .chain(function(x) {
            return List.of([x, x * 2]);
        });

List.runList(c); // [1, 2, 2, 4];

With AMD

Node files live in dist

requirejs.config({
    paths: {
        'bennu': './dist'
    }
});

require(['akh/list'], function(List) {
    ...
});

Contribute

Improvement and additions to Akh are welcome. Please report any issues or send a pull request.

Code

Akh is written in Khepri. Khepri is an ECMAScript derived language focused on functional programming that compiles to Javascript. Khepri sources are in lib directory with node output in dist_node and AMD output in dist.

# Compile all Khepri files
$ npm run build

# Run tests
$ npm test

# While developing, auto compile changed files
$ ./node_modules/.bin/khepri -w lib -o dist_node --package_manager=node

Changelog

0.8.0 - March 24, 2014

• Transformers expose their inner type with inner since there is no type system to recover this information.
• Transforming and Transformer will generated have an additional method liftInner on the output to lift from the inner Transformer's inner to the outer transformer. liftInner can be chained to lift multiple levels.

  var M = StateT (StateT (StateT (StateT Identity))));
  
  // Lift get from inner most state.
   M.liftInner.liftInner(M.inner.inner.inner.get);