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https://github.com/amarpotghan/crjdt-haskell

A Conflict-Free Replicated JSON Datatype for Haskell
https://github.com/amarpotghan/crjdt-haskell

crdt haskell json

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A Conflict-Free Replicated JSON Datatype for Haskell

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# A Conflict-Free Replicated JSON Datatype for Haskell

*crjdt-haskell* provides high level interface to CRDT which is formalised in the [paper](https://arxiv.org/pdf/1608.03960v1.pdf) by Martin Kleppmann and Alastair R. Beresford.

## Documentation

See [haddocks](https://hackage.haskell.org/package/crjdt-haskell).

## Example

```haskell

{-# LANGUAGE OverloadedStrings #-}

module Main where

import Data.Crjdt as C

-- Original state
original :: Command ()
original = doc .> key "key" =: "A"

-- First replica updates doc["key"] to "B"
replica1 :: Command ()
replica1 = original *> doc .> key "key" =: "B"

-- Second replica updates doc["key"] to "C"
replica2 :: Command ()
replica2 = original *> doc .> key "key" =: "C"

main :: IO ()
main = do
-- Sync first and second replica
let Right (r1, r2) = sync (1, replica1) (2, replica2)

let replica1' = execEval 1 r1
replica2' = execEval 2 r2

-- Both replicas converge to: {"key": {"B", "C"}}
print (document replica1' == document replica2') -- True
```

## Future work

* Improve documentation
* Aeson support
* Simplify API as described in [second version](https://arxiv.org/abs/1608.03960) of the paper

## Other implementations

* [Scala CRJDT](https://github.com/fthomas/crjdt)

## LICENSE

Copyright © 2017-2018 Amar Potghan

Distributed under BSD License.