anchor.diff:  #
   # We need to keep around at least the latest version released with a stable
   # NixOS
  -
   let
     archs = {
  -    x86_64-linux  = "linux-x86_64";
  -    i686-linux    = "linux-i686";
  +    x86_64-linux = "linux-x86_64";
  +    i686-linux = "linux-i686";
       x86_64-darwin = "darwin-x86_64";
     };
   
  
positive.code: , fetchFromGitHub
  , fetchurl
  , lib
  # Dependencies
  , boehmgc
  , coreutils
  , git
  
negative.code:   checkInputs = [ git gmp openssl readline libxml2 libyaml ];
  
    genericBinary = { version, sha256s, rel ? 1 }:
      stdenv.mkDerivation rec {
        pname = "crystal-binary";
        inherit version;
  
        src = fetchurl {
          url = "https://github.com/crystal-lang/crystal/releases/download/${version}/crystal-${version}-${toString rel}-${arch}.tar.gz";
          sha256 = sha256s.${stdenv.system};
        };
  
        buildCommand = ''
          mkdir -p $out
          tar --strip-components=1 -C $out -xf ${src}
        '';
      };
  
    commonBuildInputs = extraBuildInputs: [
      boehmgc
      libatomic_ops
      pcre
      libevent
      libyaml
      zlib
      libxml2
      openssl
    ] ++ extraBuildInputs
    ++ lib.optionals stdenv.isDarwin [ libiconv ];
  
    generic = (
      { version
      , sha256
      , binary
      , doCheck ? true
      , extraBuildInputs ? [ ]
      , buildFlags ? [ "all" "docs" ]
      }:
      lib.fix (compiler: stdenv.mkDerivation {
        pname = "crystal";
        inherit buildFlags doCheck version;
  
        src = fetchFromGitHub {
          owner = "crystal-lang";
          repo = "crystal";
          rev = version;
          inherit sha256;
        };
  
        outputs = [ "out" "lib" "bin" ];
  
        postPatch = ''
          # Add dependency of crystal to docs to avoid issue on flag changes between releases
          # https://github.com/crystal-lang/crystal/pull/8792#issuecomment-614004782
          substituteInPlace Makefile \
            --replace 'docs: ## Generate standard library documentation' 'docs: crystal ## Generate standard library documentation'
  
          substituteInPlace src/crystal/system/unix/time.cr \
            --replace /usr/share/zoneinfo ${tzdata}/share/zoneinfo
  
          ln -sf spec/compiler spec/std
  
          # Dirty fix for when no sandboxing is enabled
          rm -rf /tmp/crystal
          mkdir -p /tmp/crystal
  
          substituteInPlace spec/std/file_spec.cr \
            --replace '/bin/ls' '${coreutils}/bin/ls' \
            --replace '/usr/share' '/tmp/crystal' \
            --replace '/usr' '/tmp'
  
          substituteInPlace spec/std/process_spec.cr \
            --replace '/bin/cat' '${coreutils}/bin/cat' \
            --replace '/bin/ls' '${coreutils}/bin/ls' \
            --replace '/usr/bin/env' '${coreutils}/bin/env' \
            --replace '"env"' '"${coreutils}/bin/env"' \
            --replace '"/usr"' '"/tmp"'
  
          substituteInPlace spec/std/socket/tcp_server_spec.cr \
            --replace '{% if flag?(:gnu) %}"listen: "{% else %}"bind: "{% end %}' '"bind: "'
  
          substituteInPlace spec/std/system_spec.cr \
            --replace '`hostname`' '`${hostname}/bin/hostname`'
  
          # See https://github.com/crystal-lang/crystal/pull/8640
          substituteInPlace spec/std/http/cookie_spec.cr \
            --replace '01 Jan 2020' '01 Jan #{Time.utc.year + 2}'
  
          # See https://github.com/crystal-lang/crystal/issues/8629
          substituteInPlace spec/std/socket/udp_socket_spec.cr \
            --replace 'it "joins and transmits to multicast groups"' 'pending "joins and transmits to multicast groups"'
  
          # See https://github.com/crystal-lang/crystal/pull/8699
          substituteInPlace spec/std/xml/xml_spec.cr \
            --replace 'it "handles errors"' 'pending "handles errors"'
        '';
  
        buildInputs = commonBuildInputs extraBuildInputs;
  
        nativeBuildInputs = [ binary makeWrapper which pkg-config llvmPackages.llvm ];
  
        makeFlags = [
          "CRYSTAL_CONFIG_VERSION=${version}"
        ];
  
        LLVM_CONFIG = "${llvmPackages.llvm}/bin/llvm-config";
  
        FLAGS = [
          "--release"
          "--single-module" # needed for deterministic builds
        ];
  
        # This makes sure we don't keep depending on the previous version of
        # crystal used to build this one.
        CRYSTAL_LIBRARY_PATH = "${placeholder "lib"}/crystal";
  
        # We *have* to add `which` to the PATH or crystal is unable to build
        # stuff later if which is not available.
        installPhase = ''
          runHook preInstall
  
          install -Dm755 .build/crystal $bin/bin/crystal
          wrapProgram $bin/bin/crystal \
            --suffix PATH : ${lib.makeBinPath [ pkg-config llvmPackages.clang which ]} \
            --suffix CRYSTAL_PATH : lib:$lib/crystal \
            --suffix CRYSTAL_LIBRARY_PATH : ${
              lib.makeLibraryPath (commonBuildInputs extraBuildInputs)
            }
          install -dm755 $lib/crystal
          cp -r src/* $lib/crystal/
  
          install -dm755 $out/share/doc/crystal/api
          cp -r docs/* $out/share/doc/crystal/api/
          cp -r samples $out/share/doc/crystal/
  
          install -Dm644 etc/completion.bash $out/share/bash-completion/completions/crystal
          install -Dm644 etc/completion.zsh $out/share/zsh/site-functions/_crystal
  
          install -Dm644 man/crystal.1 $out/share/man/man1/crystal.1
  
          install -Dm644 -t $out/share/licenses/crystal LICENSE README.md
  
          mkdir -p $out
          ln -s $bin/bin $out/bin
          ln -s $lib $out/lib
  
          runHook postInstall
        '';
  
        enableParallelBuilding = true;
  
        dontStrip = true;
  
        checkTarget = "compiler_spec";
  
        preCheck = ''
          export HOME=/tmp
          mkdir -p $HOME/test
  
          export LIBRARY_PATH=${lib.makeLibraryPath checkInputs}:$LIBRARY_PATH
          export PATH=${lib.makeBinPath checkInputs}:$PATH
        '';
  
        passthru.buildCrystalPackage = callPackage ./build-package.nix {
          crystal = compiler;
        };
  
        meta = with lib; {
          description = "A compiled language with Ruby like syntax and type inference";
          homepage = "https://crystal-lang.org/";
          license = licenses.asl20;
          maintainers = with maintainers; [ david50407 fabianhjr manveru peterhoeg ];
          platforms = builtins.attrNames archs;
        };
      })
    );
  
  in
  rec {
    binaryCrystal_0_31 = genericBinary {
      version = "0.31.1";
      sha256s = {
        x86_64-linux = "0r8salf572xrnr4m6ll9q5hz6jj8q7ff1rljlhmqb1r26a8mi2ih";
        i686-linux = "0hridnis5vvrswflx0q67xfg5hryhz6ivlwrb9n4pryj5d1gwjrr";
        x86_64-darwin = "1dgxgv0s3swkc5cwawzgpbc6bcd2nx4hjxc7iw2h907y1vgmbipz";
      };
    };
  
    crystal_0_31 = generic {
      version = "0.31.1";
      sha256 = "1dswxa32w16gnc6yjym12xj7ibg0g6zk3ngvl76lwdjqb1h6lwz8";
      doCheck = false; # 5 checks are failing now
      binary = binaryCrystal_0_31;
    };
  
    crystal_0_32 = generic {
      version = "0.32.1";
      sha256 = "120ndi3nhh2r52hjvhwfb49cdggr1bzdq6b8xg7irzavhjinfza6";
      binary = crystal_0_31;
    };
  
    crystal_0_33 = generic {
      version = "0.33.0";
      sha256 = "1zg0qixcws81s083wrh54hp83ng2pa8iyyafaha55mzrh8293jbi";
      binary = crystal_0_32;
    };
  
    crystal_0_34 = generic {
      version = "0.34.0";
      sha256 = "110lfpxk9jnqyznbfnilys65ixj5sdmy8pvvnlhqhc3ccvrlnmq4";
      binary = crystal_0_33;
    };
  
    crystal_0_35 = generic {
      version = "0.35.1";
      sha256 = "0p51bjl1nsvwsm64lqq421dcsxa201w7wwq8plw4r8wqarpq0g69";
      binary = crystal_0_34;
      # Needs git to build as per https://github.com/crystal-lang/crystal/issues/9789
      extraBuildInputs = [ git ];
    };
  
    crystal_0_36 = generic {
      version = "0.36.1";
      sha256 = "sha256-5rjrvwZKM4lHpmxLyUVbi0Zw98xT+iJKonxwfUwS/Wk=";
      binary = crystal_0_35;
    };
  
    crystal = crystal_0_36;
  
    crystal2nix = callPackage ./crystal2nix.nix { };
  }
  