Delimted continuation monad and monad transformer for Akh Javascript monad transformer library

The [delimited continuation][dcont] transformer, DContT, layers delimited control over a monad. The base type, DCont, provides delimited control on its own.
The delimited continuation transformer is a monad, functor, and applicative functor.

``bash


To use as standalone package

$ npm install --save akh.dcont

To use as part of akh library

$ npm install --save akh
`

Usage

The dcont monad/transformer implements the [Fantasy Land][fl] monad, function, and applicative functor interfaces.

`js
// Delimited continuation monad
require('akh.dcont').DCont
require('akh').DCont

// Delimited continuation monad transformer
require('akh.dcont').DContT
require('akh').DContT
`

#### DCont.run(m, k), m.run(k)
Perform a delimited continuation computation m and complete with outer continuation k.

`js
const liftM2 = require('akh').base.liftM2
const dcont = require('akh').dcont

var list = liftM2.bind(null, (x, y) -> [x, y])

const c = dcont.reset((p) =>
liftM2((x, y) => x + y,
dcont.shift(p, k =>
list(k(of(1)), k(of(2))),
dcont.shift(p, k =>
list(k(of(10)), k(of(20))))

dcont.run(c, console.log) // logs: [[11, 21], [12, 22]]
`

#### DContT.run(m, k)
Same as DContT::run but for transformed types




Delimited Control Interface

All DCont operations and methods are defined on both the type and its instances.

#### M.newPrompt
Create a new unique prompt that can be used to delimit a continuation.

#### M.pushPrompt(prompt, c)
Push prompt on to the control stack, delimiting the continuation, and evaluate computation c.

#### M.withSubCont(prompt, f)
Capture the continuation delimited by prompt and call f with it. f maps the delimited continuation to a computation. The delimited control structure passed to f should be considered opaque.

#### M.pushSubCont(subk, c)
Push an entire sub continuation sunk onto the stack and evaluate computation c.

#### M.reset(f)
Delimit a continuation, calling f with delimiting prompt. f maps the prompt to a computation that is performed inside the delimited context.

#### M.shift(p, f)
Capture the continuation delimited by p, reify the continuation, and pass it to f. f can invoke the reified continuation with a computation to evaluate the rest of the delimited continuation, or return a computation directly to break out.




Contributing

Contributions are welcome.

To get started:

`bash
$ cd akh-dcont
$ npm install # install dev packages
$ npm test # run tests
``

[dcont]: http://en.wikipedia.org/wiki/Delimited_continuation