Initial commit

.envrc

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+use flake

.githooks/pre-commit

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+#!/usr/bin/env bash
+set -e
+
+filesToFormat=$(
+  git --no-pager diff --name-status --no-color --cached | \
+    awk '$1 != "D" && $2 ~ /\.hs/ {print $NF}'
+)
+
+for path in $filesToFormat
+do
+  google-java-format --replace $path
+  git add $path
+done;

.gitignore

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+# direnv
+*.sw?
+.direnv
+.gopath
+/direnv
+/direnv.test
+/dist
+/test/config
+/test/data
+/test/scenarios/inherited/.envrc
+
+# haskell
+dist
+dist-*
+cabal-dev
+*.o
+*.hi
+*.hie
+*.chi
+*.chs.h
+*.dyn_o
+*.dyn_hi
+.hpc
+.hsenv
+.cabal-sandbox/
+cabal.sandbox.config
+*.prof
+*.aux
+*.hp
+*.eventlog
+.stack-work/
+cabal.project.local
+cabal.project.local~
+.HTF/
+.ghc.environment.*

README.md

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+# hello-world
+
+## Formatting
+
+A `pre-commit` file is included in `.githooks` to ensure consistent formatting.
+Run the following to configure `git` to using it:
+
+```bash
+git config --local core.hooksPath .githooks/
+```

app/Main.hs

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+module Main where
+
+main :: IO ()
+main = putStrLn "Hello, World!"

flake.lock

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+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1644229661,
+        "narHash": "sha256-1YdnJAsNy69bpcjuoKdOYQX0YxZBiCYZo4Twxerqv7k=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "3cecb5b042f7f209c56ffd8371b2711a290ec797",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1646011258,
+        "narHash": "sha256-+aen4zu5uVp52arEcgL2maCS0zQDuG1t+Azwd/O1gN4=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "a25df4c2b79c4343bcc72ad671200e5a3e286c41",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

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+{
+  description = "A minimal Haskell flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-21.11";
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, flake-utils }: {
+    overlay = final: prev: {
+      hello-world = prev.haskellPackages.callCabal2nix "hello-world" self { };
+    };
+  } // (flake-utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = import nixpkgs {
+        inherit system;
+        overlays = [ self.overlay ];
+      };
+
+      haskell = {
+        ghc = pkgs.haskellPackages.ghc;
+        hls = pkgs.haskell-language-server.override {
+          supportedGhcVersions = [ "8107" ];
+        };
+      };
+    in
+    with pkgs; {
+      packages = { inherit hello-world; };
+
+      defaultPackage = self.packages.${system}.hello-world;
+
+      devShell = mkShell {
+        buildInputs = lib.attrValues self.packages.${system} ++ [
+          haskell.ghc
+          haskell.hls
+          gdb
+          # GHC depends on LANG so need this package to properly interpret our
+          # files with e.g. tasty-discover.
+          # https://www.reddit.com/r/Nix/comments/jyczts/nixshell_locale_issue/
+          glibcLocales
+          haskellPackages.cabal-install
+          haskellPackages.ormolu
+          haskellPackages.tasty-discover
+        ];
+      };
+    }));
+}

hello-world.cabal

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+  cabal-version:      3.0
+  name:               hello-world
+  version:            0.1.0.0
+
+  synopsis:           The Corner programming language.
+  -- A longer description of the package.
+  -- description:
+
+  -- license:
+  author:             <author>
+  maintainer:         <author>@<email>.com
+  bug-reports:        https://github.com/<owner>/<repo>/issues
+
+  -- A copyright notice.
+  -- copyright:
+  -- category:
+  extra-source-files:
+    CHANGELOG.md
+    README.md
+
+common hello-world-common
+  default-language:   Haskell2010
+  default-extensions: BangPatterns,
+                      BinaryLiterals,
+                      ConstrainedClassMethods,
+                      ConstraintKinds,
+                      DeriveDataTypeable,
+                      DeriveFoldable,
+                      DeriveFunctor,
+                      DeriveGeneric,
+                      DeriveLift,
+                      DeriveTraversable,
+                      DoAndIfThenElse,
+                      EmptyCase,
+                      EmptyDataDecls,
+                      EmptyDataDeriving,
+                      ExistentialQuantification,
+                      ExplicitForAll,
+                      -- Enabled by default, but not supported by ghc-8.10.
+                      -- FieldSelectors,
+                      FlexibleContexts,
+                      FlexibleInstances,
+                      ForeignFunctionInterface,
+                      GADTSyntax,
+                      GeneralisedNewtypeDeriving,
+                      HexFloatLiterals,
+                      ImplicitPrelude,
+                      ImportQualifiedPost,
+                      InstanceSigs,
+                      KindSignatures,
+                      MonomorphismRestriction,
+                      MultiParamTypeClasses,
+                      NamedFieldPuns,
+                      NamedWildCards,
+                      NumericUnderscores,
+                      PatternGuards,
+                      PolyKinds,
+                      PostfixOperators,
+                      RankNTypes,
+                      RelaxedPolyRec,
+                      ScopedTypeVariables,
+                      StandaloneDeriving,
+                      StandaloneKindSignatures,
+                      StarIsType,
+                      TraditionalRecordSyntax,
+                      TupleSections,
+                      TypeApplications,
+                      TypeOperators,
+                      TypeSynonymInstances
+  build-depends:      base,
+                      relude
+  mixins:             base hiding (Prelude),
+                      relude (Relude as Prelude),
+                      relude
+  ghc-options:        -Wall
+
+executable hello-world
+  import:             hello-world-common
+  main-is:            Main.hs
+  hs-source-dirs:     app

hie.yaml

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+cradle:
+  cabal: