cabal-version:       3.0
name:                stock-aeson
version:             0.1.0.0
synopsis:            Derive ToJSON / FromJSON via the stock plugin
description:
  The @stock@ plugin provides a datatype for deriving and synthesising
  instances at compile time. @stock-aeson@ extends the @stock@ with
  support for @FromJSON@ and @ToJSON@, and their higher-kinded variants.

  > {-# options_ghc -fplugin Stock #-}
  > 
  > {-# language DerivingVia #-}
  > 
  > import Stock
  > import Stock.Aeson
  > 
  > data T = MkT Int String
  >   deriving (ToJSON, FromJSON) via Stock T

  The wire format reproduces aeson's @genericToJSON \/ genericParseJSON
  defaultOptions@ exactly (a self-inverse tagged object,
  @{ "tag": "Con", "contents": [field0, …] }@), so @stock-aeson@ is a drop-in
  for @deriving stock Generic@ + @deriving anyclass (ToJSON, FromJSON)@.

  > instance DeriveStock  ToJSON     ..
  > instance DeriveStock  FromJSON   ..
  > instance DeriveStock1 ToJSON1    ..
  > instance DeriveStock1 FromJSON1  ..
  > instance DeriveStock2 ToJSON2    ..
  > instance DeriveStock2 FromJSON2  ..

  The lifted variants derive the same zero-cost way (no @Generic@ at runtime):
  parameter fields route through the supplied per-parameter encoders\/parsers, so
  the bytes still match @aeson@'s generic deriving.

  > data F a   = MkF a [a]   deriving (ToJSON1, FromJSON1) via Stock1 F
  > data P a b = MkP a b [b] deriving (ToJSON2, FromJSON2) via Stock2 P

  (@aeson@ has no @Generic2@; the arity-2 encoding is defined to coincide with
  the value encoding when both per-parameter encoders are @toJSON@.)
license:             BSD-3-Clause
license-file:        LICENSE
author:              Baldur Blöndal
maintainer:          baldur.blondal@iohk.io
category:            Type System
build-type:          Simple
tested-with:         GHC == 9.8.1, GHC == 9.10.3, GHC == 9.12.4, GHC == 9.14.1

library
  exposed-modules:   Stock.Aeson
  build-depends:     base >=4.18 && <5,
                     ghc >=9.6 && <9.16,
                     stock >=0.1 && <0.2,
                     aeson >=2 && <3
  hs-source-dirs:    .
  default-language:  GHC2021
  ghc-options:       -Wall

test-suite test
  type:              exitcode-stdio-1.0
  main-is:           Test.hs
  build-depends:     base, stock, stock-aeson, aeson, bytestring
  ghc-options:       -fplugin=Stock
  hs-source-dirs:    test
  default-language:  GHC2021

source-repository head
  type:     git
  location: https://github.com/Icelandjack/stock.git
  subdir:   aeson