nixpkgs/pkgs/development/eclipse/ecj/default.nix

{ stdenv, fetchurl, unzip, ant, gcj }:

let
  version = "3.7.2";
  date    = "201202080800";
  isGCJ   = stdenv.lib.strings.substring 0 3 gcj.name == "gcj";
  javaExec  = if isGCJ then "gij" else "java";
  javaFlags = if isGCJ then "--cp" else "-cp";
in

stdenv.mkDerivation rec {
  name = "ecj-${version}";

  src = fetchurl {
    url = "http://eclipse.ialto.org/eclipse/downloads/drops/R-${version}-${date}/ecjsrc-${version}.jar";
    sha256 = "0swyysbyfmv068x8q1c5jqpwk5zb4xahg17aypx5rwb660f8fpbm";
  };

  buildInputs = [ unzip ant gcj ];

  unpackPhase = ''
    mkdir "${name}"
    cd "${name}"
    unzip "$src"
  '';

  # Use whatever compiler Ant knows.
  buildPhase = "ant build";

  installPhase = ''
    mkdir -pv "$out/lib/java"
    cp -v *.jar "$out/lib/java"

    mkdir -pv "$out/bin"
    cat > "$out/bin/ecj" <<EOF
#! /bin/sh
exec "$(type -P ${javaExec})" ${javaFlags} "$out/lib/java/ecj.jar" org.eclipse.jdt.internal.compiler.batch.Main \$@
EOF

    chmod u+x "$out/bin/ecj"
  '';

  meta = {
    description = "The Eclipse Compiler for Java (ECJ)";

    longDescription = ''
      ECJ is an incremental Java compiler.  Implemented as an Eclipse
      builder, it is based on technology evolved from VisualAge for Java
      compiler.  In particular, it allows users to run and debug code which
      still contains unresolved errors.
    '';

    homepage = http://www.eclipse.org/jdt/core/index.php;

    # http://www.eclipse.org/legal/epl-v10.html (free software, copyleft)
    license = "EPLv1.0";
  };
}