https://github.com/sol/aeson-qq

JSON quasiquoter for Haskell
https://github.com/sol/aeson-qq

Last synced: 27 days ago
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JSON quasiquoter for Haskell

• Host: GitHub
• URL: https://github.com/sol/aeson-qq
• Owner: sol
• License: mit
• Created: 2011-04-16T14:29:44.000Z (over 13 years ago)
• Default Branch: main
• Last Pushed: 2023-05-21T12:45:15.000Z (over 1 year ago)
• Last Synced: 2024-10-29T22:00:30.403Z (about 2 months ago)
• Language: Haskell
• Homepage: http://hackage.haskell.org/package/aeson-qq
• Size: 52.7 KB
• Stars: 80
• Watchers: 40
• Forks: 14
• Open Issues: 3
• Metadata Files:
  • Readme: README.lhs
  • License: LICENSE

Awesome Lists containing this project

• awesome-json - aeson-qq - JSON quasiquoter for Haskell. (Libraries)

README

        
# aeson-qq: JSON quasiquoter for Haskell

This package exposes the function

[`aesonQQ`](http://hackage.haskell.org/package/aeson-qq/docs/Data-Aeson-QQ.html#v:aesonQQ)

that compile-time converts a string representation of a JSON value into a

[`Data.Aeson.Value`](http://hackage.haskell.org/package/aeson-0.7.0.6/docs/Data-Aeson.html#t:Value).

`aesonQQ` has the signature

```haskell ignore

aesonQQ :: QuasiQuoter

```

and is used like

```haskell

{-# LANGUAGE QuasiQuotes #-}

import Data.Aeson.QQ

import Data.Aeson (Value)

john :: Value

john = [aesonQQ| {age: 23, name: "John", likes: ["linux", "Haskell"]} |]

```

The quasiquoter can also interpolate variables like

```haskell

jane :: Value

jane = [aesonQQ| {age: #{age}, name: #{name}} |]

  where

    age = 23 :: Int

    name = "Jane"

```

where the function

[`toJSON`](http://hackage.haskell.org/package/aeson-0.7.0.6/docs/Data-Aeson.html#v:toJSON).

will be called on `age` and `name` at runtime.

You can also interpolate arbitrary Haskell expressions:

```haskell

mary :: Value

mary = [aesonQQ| {age: #{succ age}, name: "Mary"} |]

  where

    age = 23 :: Int

```

If you want to replace the name of the key in a hash you'll use the $-syntax:

```haskell

joe :: Value

joe = [aesonQQ| {$key: 23, name: "Joe"} |]

  where

    key = "age"

```