{ stdenv, fetchurl }:

assert stdenv.is64bit;
assert stdenv.isLinux || stdenv.isDarwin;

let
    osdir = if stdenv.isDarwin then "osx-64" else "linux-64";
    sha256 = if stdenv.isDarwin
             then "e50e84a017a585f9459302ce2670c04385e1f59adcacc3ecdecad79edce6ed07"
             else "6c4b776e85fe04d8efb178ccc9278bd5ee31d57b11e23886226564cdc8677d06";
in stdenv.mkDerivation rec {
    name = "k";
    version = "2019.03.21-1047_g7948682";
    src = fetchurl {
        inherit sha256;
        url = "https://anaconda.org/shaktidb/shakti/${builtins.substring 0 10 version}/download/${osdir}/shakti-${version}.tar.bz2";
    };
    phases = [ "installPhase" ];
    installPhase = ''
        mkdir -p "$out"
        tar -xf "${src}" -C "$out" "bin/${name}"
        chmod +x "$out/bin/${name}"
    '';
    meta = with stdenv.lib; {
        description = "An interpreter for the k7 language.";
        license = {
            fullName = "Evaluation Agreement";
            url = https://shakti.com/license;
            free = false;
        };
        homepage = https://shakti.com/;
        platforms = with platforms; linux ++ darwin;
    };
}