trying a thing

.github/FUNDING.yml

@@ -0,0 +1,4 @@
+github: NorfairKing
+patreon: NorfairKing
+liberapay: NorfairKing
+custom: https://cs-syd.eu/support

.github/workflows/nix-build.yml

@@ -0,0 +1,20 @@
+name: "Nix Build"
+on:
+  pull_request:
+  push:
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: cachix/install-nix-action@v12
+    - name: free disk space
+      run: |
+        sudo rm -rf /opt
+    - uses: cachix/cachix-action@v8
+      with:
+        name: yamlparse
+        extraPullNames: validity,safe-coloured-text,sydtest
+        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
+    - run: nix-build default.nix
+    - run: nix-build ci.nix

.gitignore

@@ -0,0 +1,4 @@
+.stack-work
+*.yaml.lock
+result*
+.pre-commit-config.yaml

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 Tom Sydney Kerckhove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,9 @@
+# Autodocodec
+
+Autodocodec is short for "self(auto)- documenting encoder and decoder".
+
+## Goals:
+
+* Correct-by-construction encoding and decoding, without generating code.
+* Generate automatically-correct documentation from code.
+* Fun but not important: Be able to provide instances without depending on aeson and/or yaml.

autodocodec-aeson/.gitignore

@@ -0,0 +1,2 @@
+.stack-work/
+*~

autodocodec-aeson/Changelog.md

@@ -0,0 +1,31 @@
+# Changelog
+
+## [Unreleased]
+
+### Added
+
+* `FieldParserOptional` and `FieldParserOptionalWithDefault`
+
+### Changed
+
+* `FieldParserOptional` is now called `FieldParserOptionalOrNull` and
+  `FieldParserOptionalWithDefault` is now called `FieldParserOptionalOrNullWithDefault`, but
+  if you don't use these constructors explicitly, no behaviour has changed.
+
+
+## [0.1.0.2] - 2020-10-12
+
+### Added
+
+* `prettyColourisedSchemaDoc`
+* `prettyColourisedParserDoc`
+* `prettyColourisedSchema`
+* `confDescWith`
+
+
+## [0.1.0.1] - 2020-05-10
+
+### Added
+
+* `prettySchemaDoc`
+* `prettyParserDoc`

autodocodec-aeson/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020-2021 Tom Sydney Kerckhove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

autodocodec-aeson/autodocodec-aeson.cabal

@@ -0,0 +1,56 @@
+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.34.4.
+--
+-- see: https://github.com/sol/hpack
+
+name:           autodocodec-aeson
+version:        0.0.0.0
+synopsis:       Self-documenting encoder and decoder for aeson
+homepage:       https://github.com/NorfairKing/autodocodec#readme
+bug-reports:    https://github.com/NorfairKing/autodocodec/issues
+author:         Tom Sydney Kerckhove
+maintainer:     syd@cs-syd.eu
+copyright:      2021 Tom Sydney Kerckhove
+license:        MIT
+license-file:   LICENSE
+build-type:     Simple
+
+source-repository head
+  type: git
+  location: https://github.com/NorfairKing/autodocodec
+
+library
+  exposed-modules:
+      Autodocodec.Aeson
+  other-modules:
+      Paths_autodocodec_aeson
+  hs-source-dirs:
+      src
+  build-depends:
+      aeson
+    , base >=4.7 && <5
+    , bytestring
+    , text
+  default-language: Haskell2010
+
+test-suite autodocodec-aeson-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  other-modules:
+      Autodocodec.AesonSpec
+      Paths_autodocodec_aeson
+  hs-source-dirs:
+      test/
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall
+  build-tool-depends:
+      sydtest-discover:sydtest-discover
+  build-depends:
+      aeson
+    , autodocodec
+    , autodocodec-aeson
+    , base >=4.7 && <5
+    , bytestring
+    , sydtest
+    , text
+  default-language: Haskell2010

autodocodec-aeson/package.yaml

@@ -0,0 +1,39 @@
+name: autodocodec-aeson
+version: 0.0.0.0
+github: "NorfairKing/autodocodec"
+license: MIT
+license-file: LICENSE
+author: "Tom Sydney Kerckhove"
+maintainer: "syd@cs-syd.eu"
+copyright: "2021 Tom Sydney Kerckhove"
+synopsis: Self-documenting encoder and decoder for aeson
+
+dependencies:
+- base >= 4.7 && < 5
+
+library:
+  source-dirs: src
+  dependencies:
+  - aeson
+  - autodocodec
+  - bytestring
+  - text
+
+tests:
+  autodocodec-aeson-test:
+    main: Spec.hs
+    source-dirs: test/
+    build-tools: sydtest-discover
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    - -Wall
+    dependencies:
+    - text
+    - sydtest
+    - bytestring
+    - aeson
+    - autodocodec-aeson
+    - autodocodec
+

autodocodec-aeson/src/Autodocodec/Aeson.hs

@@ -0,0 +1 @@
+module Autodocodec.Aeson where

autodocodec-aeson/test/Autodocodec/AesonSpec.hs

@@ -0,0 +1,6 @@
+module Autodocodec.AesonSpec (spec) where
+
+import Test.Syd
+
+spec :: Spec
+spec = pure ()

autodocodec-aeson/test/Spec.hs

@@ -0,0 +1 @@
+{-# OPTIONS_GHC -F -pgmF sydtest-discover #-}

autodocodec/.gitignore

@@ -0,0 +1,2 @@
+.stack-work/
+*~

autodocodec/Changelog.md

@@ -0,0 +1,31 @@
+# Changelog
+
+## [Unreleased]
+
+### Added
+
+* `FieldParserOptional` and `FieldParserOptionalWithDefault`
+
+### Changed
+
+* `FieldParserOptional` is now called `FieldParserOptionalOrNull` and
+  `FieldParserOptionalWithDefault` is now called `FieldParserOptionalOrNullWithDefault`, but
+  if you don't use these constructors explicitly, no behaviour has changed.
+
+
+## [0.1.0.2] - 2020-10-12
+
+### Added
+
+* `prettyColourisedSchemaDoc`
+* `prettyColourisedParserDoc`
+* `prettyColourisedSchema`
+* `confDescWith`
+
+
+## [0.1.0.1] - 2020-05-10
+
+### Added
+
+* `prettySchemaDoc`
+* `prettyParserDoc`

autodocodec/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020-2021 Tom Sydney Kerckhove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

autodocodec/autodocodec.cabal

@@ -0,0 +1,36 @@
+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.34.4.
+--
+-- see: https://github.com/sol/hpack
+
+name:           autodocodec
+version:        0.0.0.0
+synopsis:       Self-documenting encoder and decoder
+homepage:       https://github.com/NorfairKing/autodocodec#readme
+bug-reports:    https://github.com/NorfairKing/autodocodec/issues
+author:         Tom Sydney Kerckhove
+maintainer:     syd@cs-syd.eu
+copyright:      2021 Tom Sydney Kerckhove
+license:        MIT
+license-file:   LICENSE
+build-type:     Simple
+
+source-repository head
+  type: git
+  location: https://github.com/NorfairKing/autodocodec
+
+library
+  exposed-modules:
+      Autodocodec
+      Autodocodec.Class
+      Autodocodec.Codec
+  other-modules:
+      Paths_autodocodec
+  hs-source-dirs:
+      src
+  build-depends:
+      base >=4.7 && <5
+    , bytestring
+    , text
+  default-language: Haskell2010

autodocodec/package.yaml

@@ -0,0 +1,18 @@
+name: autodocodec
+version: 0.0.0.0
+github: "NorfairKing/autodocodec"
+license: MIT
+license-file: LICENSE
+author: "Tom Sydney Kerckhove"
+maintainer: "syd@cs-syd.eu"
+copyright: "2021 Tom Sydney Kerckhove"
+synopsis: Self-documenting encoder and decoder
+
+dependencies:
+- base >= 4.7 && < 5
+
+library:
+  source-dirs: src
+  dependencies:
+  - bytestring
+  - text

autodocodec/src/Autodocodec.hs

@@ -0,0 +1,9 @@
+module Autodocodec
+  ( -- * To make sure we definitely export everything
+    module Autodocodec.Class,
+    module Autodocodec.Codec,
+  )
+where
+
+import Autodocodec.Class
+import Autodocodec.Codec

autodocodec/src/Autodocodec/Class.hs

@@ -0,0 +1,12 @@
+{-# LANGUAGE FlexibleInstances #-}
+
+module Autodocodec.Class where
+
+import Autodocodec.Codec
+import Data.Text (Text)
+
+class HasCodec a where
+  codec :: Codec a a
+
+field :: HasCodec output => Text -> ObjectCodec output output
+field k = KeyCodec k codec

autodocodec/src/Autodocodec/Codec.hs

@@ -0,0 +1,68 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Autodocodec.Codec where
+
+import Data.Text (Text)
+
+data Codec input output where
+  NullCodec :: Codec () ()
+  BoolCodec :: Codec Bool Bool
+  StringCodec :: Codec Text Text
+  ObjectCodec :: ObjectCodec value value -> Codec value value
+  PureCodec :: output -> Codec input output
+  BimapCodec :: (oldOutput -> newOutput) -> (newInput -> oldInput) -> Codec oldInput oldOutput -> Codec newInput newOutput
+
+fmapCodec :: (oldOutput -> newOutput) -> Codec input oldOutput -> Codec input newOutput
+fmapCodec f = BimapCodec f id
+
+comapCodec :: (newInput -> oldInput) -> Codec oldInput output -> Codec newInput output
+comapCodec g = BimapCodec id g
+
+bimapCodec :: (oldOutput -> newOutput) -> (newInput -> oldInput) -> Codec oldInput oldOutput -> Codec newInput newOutput
+bimapCodec = BimapCodec
+
+instance Functor (Codec input) where
+  fmap = fmapCodec
+
+data ObjectCodec input output where
+  KeyCodec :: Text -> Codec input output -> ObjectCodec input output
+  PureObjectCodec :: output -> ObjectCodec input output
+  BimapObjectCodec :: (oldOutput -> newOutput) -> (newInput -> oldInput) -> ObjectCodec oldInput oldOutput -> ObjectCodec newInput newOutput
+  ApObjectCodec :: ObjectCodec input (output -> newOutput) -> ObjectCodec input output -> ObjectCodec input newOutput
+
+fmapObjectCodec :: (oldOutput -> newOutput) -> ObjectCodec input oldOutput -> ObjectCodec input newOutput
+fmapObjectCodec f = BimapObjectCodec f id
+
+comapObjectCodec :: (newInput -> oldInput) -> ObjectCodec oldInput output -> ObjectCodec newInput output
+comapObjectCodec g = BimapObjectCodec id g
+
+bimapObjectCodec :: (oldOutput -> newOutput) -> (newInput -> oldInput) -> ObjectCodec oldInput oldOutput -> ObjectCodec newInput newOutput
+bimapObjectCodec = BimapObjectCodec
+
+instance Functor (ObjectCodec input) where
+  fmap = fmapObjectCodec
+
+instance Applicative (ObjectCodec input) where
+  pure = pureObjectCodec
+  (<*>) = apObjectCodec
+
+pureObjectCodec :: output -> ObjectCodec input output
+pureObjectCodec = PureObjectCodec
+
+apObjectCodec :: ObjectCodec input (output -> newOutput) -> ObjectCodec input output -> ObjectCodec input newOutput
+apObjectCodec = ApObjectCodec
+
+(.=) :: ObjectCodec oldInput output -> (newInput -> oldInput) -> ObjectCodec newInput output
+(.=) = flip comapObjectCodec
+
+boolCodec :: Codec Bool Bool
+boolCodec = BoolCodec
+
+textCodec :: Codec Text Text
+textCodec = StringCodec
+
+object :: ObjectCodec value value -> Codec value value
+object = ObjectCodec

ci.nix

@@ -0,0 +1,24 @@
+let
+  sources = import ./nix/sources.nix;
+
+  versions = {
+    "lts-13_19" = "82d2c663b4dffbd635ed694bcc301284987b8097";
+    "lts-14_23" = "a87b506140a7267477103759c3f8da5b2e8d994e";
+    "lts-15_03" = "beeb24f1e939be7d85fdd64e31f13b8fe8238150";
+    "lts-16_11" = "89db531aea80df58584c9a9e3504ffd9617e6b48";
+  };
+
+  mkReleaseForVersion = version: rev:
+    let
+      pkgsf = builtins.fetchGit {
+        url = "https://github.com/NixOS/nixpkgs";
+        inherit rev;
+      };
+      p = import ./nix/pkgs.nix { inherit sources; inherit pkgsf; };
+    in
+    p.yamlparseApplicativeRelease.overrideAttrs (old: { name = "yamlparse-applicative-release-${version}"; });
+in
+{
+  release = (import ./nix/pkgs.nix { inherit sources; }).yamlparseApplicativeRelease;
+  pre-commit-check = (import ./nix/pre-commit.nix { }).run;
+} // builtins.mapAttrs mkReleaseForVersion versions

default.nix

@@ -0,0 +1,4 @@
+let
+  pkgs = import ./nix/pkgs.nix { };
+in
+pkgs.yamlparseApplicativePackages

nix/overlay.nix

@@ -0,0 +1,29 @@
+final:
+previous:
+with final.haskell.lib;
+{
+  yamlparseApplicativePackages =
+    let
+      yamlparseApplicativePkg = name:
+        doBenchmark (buildStrictly (final.haskellPackages.callCabal2nixWithOptions name (final.gitignoreSource (../. + "/${name}")) "--no-hpack" { }));
+    in
+    final.lib.genAttrs [
+      "yamlparse-applicative"
+      "yamlparse-applicative-demo"
+    ]
+      yamlparseApplicativePkg;
+
+  yamlparseApplicativeRelease =
+    final.symlinkJoin {
+      name = "yamlparse-applicative-release";
+      paths = final.lib.attrValues final.yamlparseApplicativePackages;
+    };
+
+  haskellPackages = previous.haskellPackages.override (
+    old: {
+      overrides = final.lib.composeExtensions (old.overrides or (_: _: { })) (
+        self: super: final.yamlparseApplicativePackages
+      );
+    }
+  );
+}

nix/pkgs.nix

@@ -0,0 +1,17 @@
+{ sources ? import ./sources.nix
+, pkgsf ? sources.nixpkgs
+}:
+let
+  pkgs =
+    import pkgsf {
+      overlays = [
+        (import (sources.validity + "/nix/overlay.nix"))
+        (import (sources.safe-coloured-text + "/nix/overlay.nix"))
+        (import (sources.sydtest + "/nix/overlay.nix"))
+        (final: previous: { inherit (import sources.gitignore { inherit (final) lib; }) gitignoreSource; })
+        (import ./overlay.nix)
+      ];
+      config.allowUnfree = true;
+    };
+in
+pkgs

nix/pre-commit.nix

@@ -0,0 +1,21 @@
+{ sources ? import ./sources.nix }:
+let
+  pre-commit-hooks = import sources.pre-commit-hooks;
+in
+{
+  run = pre-commit-hooks.run {
+    src = ../.;
+    hooks = {
+      hlint.enable = true;
+      hpack.enable = true;
+      nixpkgs-fmt.enable = true;
+      ormolu.enable = true;
+    };
+  };
+  tools = with pre-commit-hooks; [
+    hlint
+    hpack
+    nixpkgs-fmt
+    ormolu
+  ];
+}

nix/sources.json

@@ -0,0 +1,86 @@
+{
+    "gitignore": {
+        "branch": "master",
+        "description": "Nix function for filtering local git sources",
+        "homepage": "",
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "rev": "211907489e9f198594c0eb0ca9256a1949c9d412",
+        "sha256": "06j7wpvj54khw0z10fjyi31kpafkr6hi1k0di13k1xp8kywvfyx8",
+        "type": "tarball",
+        "url": "https://github.com/hercules-ci/gitignore.nix/archive/211907489e9f198594c0eb0ca9256a1949c9d412.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "niv": {
+        "branch": "master",
+        "description": "Easy dependency management for Nix projects",
+        "homepage": "https://github.com/nmattia/niv",
+        "owner": "nmattia",
+        "repo": "niv",
+        "rev": "94080ae8286024820c570a2a24ed7c36d7ad04a9",
+        "sha256": "0wlk52zwlrq727x3z1vg9d9qq4zw62ab5jzg4068iqb6hyb0cr0w",
+        "type": "tarball",
+        "url": "https://github.com/nmattia/niv/archive/94080ae8286024820c570a2a24ed7c36d7ad04a9.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs": {
+        "branch": "nixos-21.05",
+        "description": "Nix Packages collection",
+        "homepage": "",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "aa576357673d609e618d87db43210e49d4bb1789",
+        "sha256": "1868s3mp0lwg1jpxsgmgijzddr90bjkncf6k6zhdjqihf0i1n2np",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/aa576357673d609e618d87db43210e49d4bb1789.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "pre-commit-hooks": {
+        "branch": "master",
+        "description": "Seamless integration of https://pre-commit.com git hooks with Nix.",
+        "homepage": "",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "2e7fac06108b4fc81f5ff9ed9a02bc4f6ede7001",
+        "sha256": "17xlb7cb1n6cyw8my6ks4iacrz49a6wfqrdj2gvjc52qc91wxvj7",
+        "type": "tarball",
+        "url": "https://github.com/cachix/pre-commit-hooks.nix/archive/2e7fac06108b4fc81f5ff9ed9a02bc4f6ede7001.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "safe-coloured-text": {
+        "branch": "master",
+        "description": null,
+        "homepage": "https://cs-syd.eu/posts/2021-03-07-safe-coloured-text",
+        "owner": "NorfairKing",
+        "repo": "safe-coloured-text",
+        "rev": "d5788740052925aebf1dec1cf1669f66d3a35120",
+        "sha256": "0mrrfnvvwvdq2cf2figvan8z4jk0bypa0xmg11n3af6vsjryih43",
+        "type": "tarball",
+        "url": "https://github.com/NorfairKing/safe-coloured-text/archive/d5788740052925aebf1dec1cf1669f66d3a35120.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "sydtest": {
+        "branch": "master",
+        "description": "A modern testing framework for Haskell with good defaults and advanced testing features.",
+        "homepage": "",
+        "owner": "NorfairKing",
+        "repo": "sydtest",
+        "rev": "0125c6d6d17d44753c793adc8dcaa4284fef2b7d",
+        "sha256": "1mxvwngv7md0z7jddn4ffpqffs6qp8ka3ffbw3v545q5aijnkbhy",
+        "type": "tarball",
+        "url": "https://github.com/NorfairKing/sydtest/archive/0125c6d6d17d44753c793adc8dcaa4284fef2b7d.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "validity": {
+        "branch": "master",
+        "description": "Validity and validity-based testing",
+        "homepage": "https://www.youtube.com/watch?v=eIs9qNh17SM",
+        "owner": "NorfairKing",
+        "repo": "validity",
+        "rev": "549f92de456dd7fbf21b84f2f6fdca9a3c6506d9",
+        "sha256": "1gbs61kcpyd8nha1g13dsmkhslkbmhxyjfb5fmg2nwqayxvdha58",
+        "type": "tarball",
+        "url": "https://github.com/NorfairKing/validity/archive/549f92de456dd7fbf21b84f2f6fdca9a3c6506d9.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    }
+}

nix/sources.nix

@@ -0,0 +1,177 @@
+# This file has been generated by Niv.
+
+let
+
+  #
+  # The fetchers. fetch_<type> fetches specs of type <type>.
+  #
+
+  fetch_file = pkgs: name: spec:
+    let
+      name' = sanitizeName name + "-src";
+    in
+    if spec.builtin or true then
+      builtins_fetchurl { inherit (spec) url sha256; name = name'; }
+    else
+      pkgs.fetchurl { inherit (spec) url sha256; name = name'; };
+
+  fetch_tarball = pkgs: name: spec:
+    let
+      name' = sanitizeName name + "-src";
+    in
+    if spec.builtin or true then
+      builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
+    else
+      pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
+
+  fetch_git = name: spec:
+    let
+      ref =
+        if spec ? ref then spec.ref else
+        if spec ? branch then "refs/heads/${spec.branch}" else
+        if spec ? tag then "refs/tags/${spec.tag}" else
+        abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!";
+    in
+    builtins.fetchGit { url = spec.repo; inherit (spec) rev; inherit ref; };
+
+  fetch_local = spec: spec.path;
+
+  fetch_builtin-tarball = name: throw
+    ''[${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
+        $ niv modify ${name} -a type=tarball -a builtin=true'';
+
+  fetch_builtin-url = name: throw
+    ''[${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
+        $ niv modify ${name} -a type=file -a builtin=true'';
+
+  #
+  # Various helpers
+  #
+
+  # https://github.com/NixOS/nixpkgs/pull/83241/files#diff-c6f540a4f3bfa4b0e8b6bafd4cd54e8bR695
+  sanitizeName = name:
+    (
+      concatMapStrings (s: if builtins.isList s then "-" else s)
+        (
+          builtins.split "[^[:alnum:]+._?=-]+"
+            ((x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0) name)
+        )
+    );
+
+  # The set of packages used when specs are fetched using non-builtins.
+  mkPkgs = sources: system:
+    let
+      sourcesNixpkgs =
+        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { inherit system; };
+      hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
+      hasThisAsNixpkgsPath = <nixpkgs> == ./.;
+    in
+    if builtins.hasAttr "nixpkgs" sources
+    then sourcesNixpkgs
+    else if hasNixpkgsPath && ! hasThisAsNixpkgsPath then
+      import <nixpkgs> { }
+    else
+      abort
+        ''
+          Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
+          add a package called "nixpkgs" to your sources.json.
+        '';
+
+  # The actual fetching function.
+  fetch = pkgs: name: spec:
+
+    if ! builtins.hasAttr "type" spec then
+      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
+    else if spec.type == "file" then fetch_file pkgs name spec
+    else if spec.type == "tarball" then fetch_tarball pkgs name spec
+    else if spec.type == "git" then fetch_git name spec
+    else if spec.type == "local" then fetch_local spec
+    else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
+    else if spec.type == "builtin-url" then fetch_builtin-url name
+    else
+      abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
+
+  # If the environment variable NIV_OVERRIDE_${name} is set, then use
+  # the path directly as opposed to the fetched source.
+  replace = name: drv:
+    let
+      saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
+      ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
+    in
+    if ersatz == "" then drv else
+      # this turns the string into an actual Nix path (for both absolute and
+      # relative paths)
+    if builtins.substring 0 1 ersatz == "/" then /. + ersatz else /. + builtins.getEnv "PWD" + "/${ersatz}";
+
+  # Ports of functions for older nix versions
+
+  # a Nix version of mapAttrs if the built-in doesn't exist
+  mapAttrs = builtins.mapAttrs or (
+    f: set: with builtins;
+    listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
+  );
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
+  range = first: last: if first > last then [ ] else builtins.genList (n: first + n) (last - first + 1);
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
+  stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
+  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
+  concatMapStrings = f: list: concatStrings (map f list);
+  concatStrings = builtins.concatStringsSep "";
+
+  # https://github.com/NixOS/nixpkgs/blob/8a9f58a375c401b96da862d969f66429def1d118/lib/attrsets.nix#L331
+  optionalAttrs = cond: as: if cond then as else { };
+
+  # fetchTarball version that is compatible between all the versions of Nix
+  builtins_fetchTarball = { url, name ? null, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchTarball;
+    in
+    if lessThan nixVersion "1.12" then
+      fetchTarball ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
+    else
+      fetchTarball attrs;
+
+  # fetchurl version that is compatible between all the versions of Nix
+  builtins_fetchurl = { url, name ? null, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchurl;
+    in
+    if lessThan nixVersion "1.12" then
+      fetchurl ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
+    else
+      fetchurl attrs;
+
+  # Create the final "sources" from the config
+  mkSources = config:
+    mapAttrs
+      (
+        name: spec:
+          if builtins.hasAttr "outPath" spec
+          then
+            abort
+              "The values in sources.json should not have an 'outPath' attribute"
+          else
+            spec // { outPath = replace name (fetch config.pkgs name spec); }
+      )
+      config.sources;
+
+  # The "config" used by the fetchers
+  mkConfig =
+    { sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
+    , sources ? if isNull sourcesFile then { } else builtins.fromJSON (builtins.readFile sourcesFile)
+    , system ? builtins.currentSystem
+    , pkgs ? mkPkgs sources system
+    }: rec {
+      # The sources, i.e. the attribute set of spec name to spec
+      inherit sources;
+
+      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
+      inherit pkgs;
+    };
+
+in
+mkSources (mkConfig { }) // { __functor = _: settings: mkSources (mkConfig settings); }

shell.nix

@@ -0,0 +1,13 @@
+let
+  sources = import ./nix/sources.nix;
+  pkgs = import ./nix/pkgs.nix { inherit sources; };
+  pre-commit = import ./nix/pre-commit.nix { inherit sources; };
+in
+pkgs.haskell.lib.buildStackProject {
+  name = "yamlparse-applicative-shell";
+  buildInputs = with pkgs; [
+    (import sources.niv { }).niv
+    zlib
+  ] ++ pre-commit.tools;
+  shellHook = pre-commit.run.shellHook;
+}

stack.yaml

@@ -0,0 +1,27 @@
+resolver: nightly-2021-05-10
+packages:
+- autodocodec
+- autodocodec-aeson
+  # - autodocodec-yaml
+extra-deps:
+
+- github: NorfairKing/validity
+  commit: 549f92de456dd7fbf21b84f2f6fdca9a3c6506d9
+  subdirs:
+  - validity
+  - genvalidity
+  - genvalidity-sydtest
+- github: NorfairKing/safe-coloured-text
+  commit: b8333a8956975beab54d00fceaa835ee97c3347d
+  subdirs:
+    - safe-coloured-text
+    - safe-coloured-text-terminfo
+- github: NorfairKing/sydtest
+  commit: 0125c6d6d17d44753c793adc8dcaa4284fef2b7d
+  subdirs:
+    - sydtest
+    - sydtest-discover
+- envparse-0.4.1@sha256:989902e6368532548f61de1fa245ad2b39176cddd8743b20071af519a709ce30,2842
+
+nix:
+  shell-file: shell.nix