Writer

The Writer monad is one that has - in addition to a transformable value in its monadic context - a log proviso. It allows for accumulation of logs throughout multiple computations.

writer

writer(result, output)

writer :: a -> w -> Writer (a, w)

Create a new instance of the writer monad.

Since:

• bingo-functional - v1.11.0
• bingo-functional-js - v0.1.0

Argument(s):

• result - Primary monad input
• output - Ancillary log data

JavaScript

import { writer } from 'bingo-functional-js'
const result = writer(2, 'put 2')

PHP

use function Chemem\Bingo\Functional\Functors\Monads\Writer\writer;
$result = writer(2, 'put 2');

tell

tell(msg)

tell :: w -> m ()

Produces a Writer monad's output.

Since:

• bingo-functional - v1.11.0
• bingo-functional-js - v0.1.0

Argument(s):

• msg - Writer monad output

JavaScript

import { tell } from 'bingo-functional-js'
const result = tell('put 2').map((x) => x + 2)

PHP

use function Chemem\Bingo\Functional\Functors\Monads\{  bind,  Writer\tell};
$result = tell('put 2')->map(fn ($x): int => $x + 2);

runWriter

runWriter(writer)

runWriter :: Writer a w -> (a, w)

Unwraps a writer computation as a (result, output) pair.

Since:

• bingo-functional - v1.11.0
• bingo-functional-js - v0.1.0

Argument(s):

• writer - Instance of Writer monad

JavaScript

import { writer, runWriter } from 'bingo-functional-js'
const result = writer(2, 'put 2')
runWriter(result)

PHP

use function Chemem\Bingo\Functional\Functors\Monads\Writer\{  writer,  runWriter};
$result = writer(2, 'put 2');
runWriter($result);

execWriter

execWriter(writer)

execWriter :: Writer a w -> w

Extracts the output from a writer computation.

Since:

• bingo-functional - v1.11.0
• bingo-functional-js - v0.1.0

Argument(s):

• writer - Instance of Writer monad

JavaScript

import { writer, execWriter } from 'bingo-functional-js'
const result = writer(2, 'put 2')
execWriter(result)

PHP

use function Chemem\Bingo\Functional\Functors\Monads\Writer\{  writer,  execWriter};
$result = writer(2, 'put 2');
execWriter($result);