roundtrip-aeson: Un-/parse JSON with roundtrip invertible syntax definitions.

[ bsd3, data, library ] [ Propose Tags ]

Verily, Un-/parse JSON with roundtrip invertible syntax definitions.


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Versions 0.2.0.0, 0.2.0.1, 0.2.0.2, 0.3.0.2
Change log ChangeLog
Dependencies aeson, base (>=4.7 && <5), bytestring, containers (==0.5.*), lens, lens-aeson, roundtrip (==0.2.*), scientific, text (==1.2.*), unordered-containers, vector [details]
License BSD-3-Clause
Copyright Copyright 2014-2015 Anchor Systems and others.
Author Thomas Sutton <me@thomas-sutton.id.au>, Christian Marie <christian@ponies.io>
Maintainer Christian Marie
Category Data
Home page https://github.com/christian-marie/roundtrip-aeson
Source repo head: git clone https://github.com/christian-marie/roundtrip-aeson
Uploaded by ChristianMarie at Sun Oct 14 07:55:31 UTC 2018
Distributions NixOS:0.3.0.2
Downloads 441 total (84 in the last 30 days)
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Status Docs not available [build log]
All reported builds failed as of 2018-10-14 [all 3 reports]
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Modules

  • Data
    • Aeson
      • Data.Aeson.Roundtrip

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Readme for roundtrip-aeson-0.3.0.2

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Roundtrip Aeson

Build Status

roundtrip allows you to write invertible syntax descriptions -- or, to put it another way, a parser and pretty printer combined -- for String or XML data. This package extends this to support constructing and destructing JSON documents.

Example

Using roundtrip-aeson is relatively straightforward:

  1. Define your data type;

  2. Define partial isomorphisms for the constructors (probably using the template haskell);

  3. Describe the syntax of its JSON representation; and

  4. Use that representation to build and parse JSON.

import Data.Aeson.RoundTrip

data Invoice
    = Unpaid Bool Integer Bool
    | Paid Double
  deriving (Show)

defineIsomorphisms ''Invoice

invoiceSyntax :: JsonSyntax s => s Invoice
invoiceSyntax =
    unpaid
        <$> jsonField "overdue" jsonBool
        <*> jsonField "total"   jsonIntegral
        <*> jsonField "warned"  jsonBool
    <|> paid
        <$> jsonField "total"   jsonRealFrac

main :: IO ()
main = do
    -- Build a JSON representation.
    let Right x = runBuilder invoiceSyntax $ Unpaid False 40 [False]
    L.putStrLn $ encode x
    -- Parse a JSON representation.
    print $ runParser invoiceSyntax x

See tests/demo.hs for the complete source of this example.