diff --git a/nix/lib.nix b/nix/lib.nix
index 3ad473e7d..0fe10056b 100644
--- a/nix/lib.nix
+++ b/nix/lib.nix
@@ -22,7 +22,7 @@ in rec {
 
   opam2nix = { src, opamFile ? findOpamFile src, ... }@args:
     pkgs.runCommandNoCC (args.pname or opamFile + ".nix") args
-    "cat ${src}/${opamFile} | ${opam-parser} > $out";
+    "cat ${src}/${opamFile} | ${pkgs.glibc.bin}/bin/iconv -c -f utf-8 -t ascii | ${opam-parser} > $out";
 
   traverseOPAMRepo = repo: self: super:
     let
@@ -33,25 +33,42 @@ in rec {
         (builtins.attrNames (builtins.readDir "${repo}/packages/${pkg}"));
       latestVersion = builtins.foldl'
         (x: acc: if builtins.compareVersions x acc == 1 then x else acc) "";
-      opamPkgs = builtins.mapAttrs (n: _:
+      opamPkgs = builtins.mapAttrs (name: _:
         let
-          v = latestVersion (versions n);
-          file = opam2nix {
-            src = "${repo}/packages/${n}/${n}.${v}";
-            opamFile = "opam";
-            pname = n;
-            version = v;
-          };
-        in self.callPackage file { }) pkgNames;
+          file = version:
+            opam2nix {
+              src = "${repo}/packages/${name}/${name}.${version}";
+              opamFile = "opam";
+              pname = name;
+              inherit version;
+            };
+          package = version: self.callPackage (file version) { };
+          latest = package (latestVersion (versions name));
+          others = map package (versions name);
+        in latest // {
+          versions = builtins.listToAttrs (map (p: {
+            name = p.version;
+            value = p;
+          }) others);
+        }) pkgNames;
     in opamPkgs;
 
-  callOPAMPackage' = callPackage: src: newAttrs: overrides:
-    (callPackage (opam2nix (newAttrs // { inherit src; }))
-      overrides).overrideAttrs ({ buildInputs, src ? src, ... }:
-        {
-          inherit src;
-          buildInputs = buildInputs ++ newAttrs.extraBuildInputs or [ ];
-          propagatedBuildInputs = buildInputs
-            ++ newAttrs.extraBuildInputs or [ ];
-        } // newAttrs);
+  traverseOPAMRepo' = repo: self: super:
+    let traversed = traverseOPAMRepo repo self super;
+    in traversed // builtins.mapAttrs (name: v:
+      v // {
+        versions = (traversed.${name} or { versions = { }; }).versions;
+      }) super;
+
+  callOPAMPackage = self: super: {
+    callOPAMPackage = src: newAttrs: overrides:
+      (self.callPackage (opam2nix (newAttrs // { inherit src; }))
+        overrides).overrideAttrs ({ buildInputs, ... }@args:
+          {
+            inherit src;
+            buildInputs = buildInputs ++ newAttrs.extraBuildInputs or [ ];
+            propagatedBuildInputs = buildInputs
+              ++ newAttrs.extraBuildInputs or [ ];
+          } // newAttrs);
+  };
 }
diff --git a/nix/ocaml-overlay.nix b/nix/ocaml-overlay.nix
index 377ef67d7..c750a9f27 100644
--- a/nix/ocaml-overlay.nix
+++ b/nix/ocaml-overlay.nix
@@ -2,18 +2,82 @@
 self: super:
 let lib = import ./lib.nix self;
 in {
-  ocamlPackages = super.ocaml-ng.ocamlPackages_4_09.overrideScope'
+  ocamlPackages = super.ocaml-ng.ocamlPackages_4_07.overrideScope'
     (builtins.foldl' self.lib.composeExtensions (_: _: { }) [
-      (oself: osuper:
-        (lib.traverseOPAMRepo (builtins.fetchTarball
-          "https://github.com/ocaml/opam-repository/archive/master.tar.gz") oself osuper)
-        // osuper)
-      (lib.traverseOPAMRepo ../../tezos-opam-repository)
+      (lib.traverseOPAMRepo' sources.opam-repository)
+      (lib.traverseOPAMRepo sources.tezos-opam-repository)
+      (lib.callOPAMPackage)
       (oself: osuper:
         with oself; {
           ocamlfind = findlib;
           lwt = lwt4;
-          bigstring-unix = null;
+          bigstring = osuper.bigstring.overrideAttrs (_: { doCheck = false; });
+          xmldiff =
+            osuper.xmldiff.overrideAttrs (_: { src = sources.xmldiff; });
+          ipaddr = osuper.ipaddr.versions."4.0.0";
+          conduit = osuper.conduit.versions."2.1.0";
+          conduit-lwt-unix = osuper.conduit-lwt-unix.versions."2.0.2";
+          cohttp-lwt-unix = osuper.cohttp-lwt-unix.versions."2.4.0";
+          cohttp-lwt = osuper.cohttp-lwt.versions."2.4.0";
+          macaddr = osuper.macaddr.versions."4.0.0";
+          ocaml-migrate-parsetree = osuper.ocaml-migrate-parsetree.versions."1.4.0";
+          ppx_tools_versioned = osuper.ppx_tools_versioned.versions."5.2.3";
+          tezos-protocol-compiler = osuper.tezos-protocol-compiler.overrideAttrs
+            (oa: {
+              buildInputs = oa.buildInputs ++ [ oself.pprint ];
+              postInstall =
+                "ln -s $out/lib/ocaml/*/site-lib/tezos-protocol-compiler/* $out";
+            });
+          conf-gmp = self.gmp;
+          conf-libev = self.libev;
+          conf-hidapi = self.hidapi;
+          conf-pkg-config = self.pkg-config;
+
+          tezos-protocol-006-PsCARTHA =
+            oself.callOPAMPackage ../vendors/ligo-utils/tezos-protocol-alpha {
+              pname = "tezos-protocol-006-PsCARTHA";
+              version = "0.0.0";
+              opamFile = "tezos-protocol-006-PsCARTHA.opam";
+            } { };
+
+          tezos-protocol-006-PsCARTHA-parameters = oself.callOPAMPackage
+            ../vendors/ligo-utils/tezos-protocol-alpha-parameters {
+              pname = "tezos-protocol-006-PsCARTHA-parameters";
+              version = "0.0.0";
+            } { };
+
+          tezos-utils =
+            oself.callOPAMPackage ../vendors/ligo-utils/tezos-utils {
+              pname = "tezos-utils";
+              version = "0.1";
+            } { };
+          proto-alpha-utils =
+            oself.callOPAMPackage ../vendors/ligo-utils/proto-alpha-utils {
+              pname = "proto-alpha-utils";
+              version = "0.1";
+              extraBuildInputs =
+                [ oself.tezos-protocol-006-PsCARTHA-parameters ];
+            } { };
+          simple-utils =
+            oself.callOPAMPackage ../vendors/ligo-utils/simple-utils {
+              pname = "simple-utils";
+              version = "0.1";
+            } { };
+          tezos-memory-proto-alpha =
+            oself.callOPAMPackage ../vendors/ligo-utils/memory-proto-alpha {
+              pname = "tezos-memory-proto-alpha";
+              version = "0.0.0";
+            } { };
+          michelson-parser = oself.callOPAMPackage
+            ../vendors/ligo-utils/tezos-utils/michelson-parser {
+              pname = "michelson-parser";
+              version = "0.0.0";
+            } { ocamlfind = oself.findlib; };
+
+          ligo = oself.callOPAMPackage ../. {
+            version = "0.1";
+            extraBuildInputs = with oself; [ ppx_tools_versioned getopt ];
+          } { };
         })
     ]);
 }
diff --git a/nix/opam-parser.hs b/nix/opam-parser.hs
index a71315252..5c8cbd705 100644
--- a/nix/opam-parser.hs
+++ b/nix/opam-parser.hs
@@ -8,65 +8,121 @@ import Control.Monad (void)
 import Data.List (intersperse, nub, isPrefixOf)
 import qualified Control.Applicative as A (optional)
 
-type Package = String
-
 data OPAM
   = OPAM
   { name :: Maybe String
   , version :: Maybe String
-  , depends :: Maybe [String]
-  , build :: Maybe [[String]]
-  , source :: Maybe (String)
+  , nativeBuildInputs :: Maybe [String]
+  , buildInputs :: Maybe [String]
+  , buildPhase :: Maybe [[String]]
+  , checkInputs :: Maybe [String]
+  , checkPhase :: Maybe [[String]]
+  , source :: Maybe String
   } deriving Show
-
 opam2nix :: OPAM -> String
 opam2nix OPAM {..} =
-  let depends' = nub ([ "findlib", "ocaml", "opaline", "dune" ]
-                      ++ (map (\case 'b':'a':'s':'e':_ -> "base"; s -> s)
-                          $ mconcat $ maybeToList depends))
+  let
+    normalize = nub . map (\case 'b':'a':'s':'e':'-':_ -> "base"; s -> s)
+    buildInputs' = [ "findlib" ] ++ mconcat (maybeToList buildInputs);
+    checkInputs' = mconcat $ maybeToList checkInputs
+    nativeBuildInputs' = [ "dune", "opaline", "ocaml", "findlib" ]
+      ++ (if any (isPrefixOf "conf-")
+           (buildInputs' ++ checkInputs' ++ mconcat (maybeToList nativeBuildInputs))
+           then ["conf-pkg-config"]
+           else [])
+      ++ mconcat (maybeToList nativeBuildInputs)
+    inputs = buildInputs' ++ checkInputs' ++ nativeBuildInputs'
+    deps = mconcat $ intersperse ", " $ normalize $ inputs
+    sepspace = mconcat . intersperse " " . normalize
+    preparephase = mconcat . intersperse " " . mconcat . intersperse ["\n"]
   in
-    "{ stdenv, fetchzip, " <> (mconcat $ intersperse ", " depends') <> " }:\n"
+    "{ stdenv, fetchzip, " <>deps<> " }:\n"
   <>"stdenv.mkDerivation rec {\n"
-  <>foldMap (\name -> "  pname = \""<>name<>"\";\n") name
-  <>foldMap (\version -> "  version = \""<>version<>"\";\n") version
+  <>foldMap (\name' -> "  pname = \""<>name'<>"\";\n") name
+  <>foldMap (\version' -> "  version = \""<>version'<>"\";\n") version
   <>foldMap (\url -> "  src = builtins.fetchTarball { url = \""<>url<>"\"; };\n") source
-  <>"  buildInputs = [ "<>(mconcat $ intersperse " " depends')<>" ];\n"
+  <>"  buildInputs = [ "<>sepspace buildInputs'<>" ];\n"
+  <>"  checkInputs = [ "<>sepspace checkInputs'<>" ];\n"
+  <>"  nativeBuildInputs = [ "<>sepspace nativeBuildInputs'<>" ];\n"
   <>"  propagatedBuildInputs = buildInputs;\n"
-  <>foldMap (\build -> "  buildPhase = ''runHook preBuild\n"<>(mconcat $ intersperse " " $ mconcat $ intersperse ["\n"] $ build)<>"\nrunHook postBuild\n'';\n") build
-  <>(if "dune" `elem` depends' then "  installPhase = ''\nrunHook preInstall\nopaline -prefix $out -libdir $OCAMLFIND_DESTDIR\nrunHook postInstall\n'';\n" else "")
+  <>"  propagatedNativeBuildInputs = nativeBuildInputs;\n"
+  <>foldMap (\buildPhase' ->
+                "  buildPhase = ''runHook preBuild\n"
+              <> preparephase buildPhase'
+              <>"\nrunHook postBuild\n'';\n") buildPhase
+  <>foldMap (\checkPhase' ->
+                "  checkPhase = ''runHook preCheck\n"
+              <>preparephase checkPhase'
+              <>"\nrunHook postCheck\n'';\n") checkPhase
+  <>"  installPhase = ''\nrunHook preInstall\nopaline -prefix $out -libdir $OCAMLFIND_DESTDIR\nrunHook postInstall\n'';\n"
+
   <>"}\n"
 
-getSha512 :: [String] -> String
-getSha512 cs = (tail.tail.tail.tail.tail.tail.tail) $ head $ filter (isPrefixOf "sha512=") cs
+update :: Maybe a -> a -> Maybe a
+update old new = if isNothing old then Just new else old
 
 evaluateField :: OPAM -> Field -> OPAM
-evaluateField o@(OPAM {..}) = \case
-  Name s -> o { name = if isNothing name then Just s else name }
-  Version s -> o { version = if isNothing version then Just s else version }
-  Depends s -> o { depends = if isNothing depends then Just s else depends }
-  Build e -> o { build = if isNothing build then Just (fmap (evaluateExp $ fromJust $ name) <$> e) else build }
-  URL url -> o { source = if isNothing source then Just url else source }
+evaluateField o@OPAM {..} = \case
+  Name s -> o { name = update name s }
+  Version s -> o { version = update version s }
+  Depends s -> o {
+    buildInputs = update buildInputs $
+      fmap identifier $ filter (\(Package _ info) -> not $ ("with-test" `elem` info || "build" `elem` info)) s,
+    nativeBuildInputs = update nativeBuildInputs $
+      fmap identifier $ filter (\(Package _ info) -> "build" `elem` info) s,
+    checkInputs = update checkInputs $
+      fmap identifier $ filter (\(Package _ info) -> "with-test" `elem` info) s
+  }
+  Build e -> o {
+    buildPhase = update buildPhase
+      $ fmap ((fmap evaluateExp) . command) $ filter (\(Command _ info) -> not $ "with-test" `elem` info) e,
+    checkPhase = update checkPhase
+      $ fmap ((fmap evaluateExp) . command) $ filter (\(Command _ info) -> "with-test" `elem` info) e
+  }
+  URL url -> o { source = update source url}
   Other _ -> o
 
 evaluateFields :: OPAM -> [Field] -> OPAM
 evaluateFields = foldl evaluateField
 
+data Package
+  = Package
+  { identifier :: String
+  , additionalPackageInfo :: [String]
+  } deriving Show
+
+data Exp = Str String | Var String deriving Show
+
+data Command
+  = Command
+  { command :: [Exp]
+  , additionalCommandInfo :: [String]
+  } deriving Show
+
 data Field
   = Name String
   | Version String
   | Depends [Package]
-  | Build [[Exp]]
+  | Build [Command]
   | URL String
   | Other String
   deriving Show
 
-data Exp = Raw String | NameVar | JobsVar deriving Show
-
-evaluateExp :: String -> Exp -> String
-evaluateExp name = \case
-  Raw s -> s
-  NameVar -> name
-  JobsVar -> "1"
+evaluateExp :: Exp -> String
+evaluateExp =
+  let
+    repl ('%':'{':xs) = '$':'{':repl xs
+    repl (':':_:_:_:'}':'%':xs) = '}':repl xs
+    repl (x:xs) = x:repl xs
+    repl "" = ""
+    in
+    \case
+      Str s -> repl s
+      Var "name" -> "${pname}"
+      Var "make" -> "make"
+      Var "prefix" -> "$out"
+      Var "jobs" -> "1"
+      Var s -> "${"<>s<>"}"
 
 opamFile :: ParsecT String u Identity [Field]
 opamFile = many field <* eof
@@ -77,10 +133,10 @@ field = Name <$> fieldParser "name" stringParser
     <|> Depends <$> fieldParser "depends" (listParser packageParser)
     <|> Build <$> fieldParser "build" (pure <$> try commandParser <|> listParser commandParser)
     <|> sectionParser "url" (URL <$> (fieldParser "src" stringParser <* many (noneOf "}")))
-    <|> Other <$> ((many (noneOf "\n")) <* char '\n')
+    <|> Other <$> (many (noneOf "\n") <* char '\n')
 
 fieldParser :: String -> ParsecT String u Identity t -> ParsecT String u Identity t
-fieldParser name valueParser = try $ between (string (name<>":") >> (many $ oneOf " \n")) (many $ oneOf " \n") valueParser <* commentParser
+fieldParser name valueParser = try $ between (string (name<>":") >> many (oneOf " \n")) (many $ oneOf " \n") valueParser <* commentParser
 
 sectionParser :: String -> ParsecT String u Identity t -> ParsecT String u Identity t
 sectionParser name valueParser = try $ between (string name >> many (oneOf " ") >> string "{" >> many (oneOf " \n")) (many (oneOf " \n") >> char '}' >> char '\n') valueParser
@@ -89,15 +145,19 @@ stringParser :: ParsecT String u Identity String
 stringParser = between (char '"') (char '"') (many $ noneOf "\"")
 
 expParser :: ParsecT String u Identity Exp
-expParser = try (string "name" >> return NameVar)
-        <|> try (string "jobs" >> return JobsVar)
-        <|> Raw <$> stringParser
+expParser = try (Str <$> stringParser)
+        <|> Var <$> many1 (noneOf " \n\"{}[]")
 
-commandParser :: ParsecT String u Identity [Exp]
+additionalInfoParser :: ParsecT String u Identity [String]
+additionalInfoParser = option [] $ try
+  $ between (many (char ' ') >> char '{') (char '}')
+  ((many $ noneOf " &}") `sepBy` (oneOf " &"))
+
+commandParser :: ParsecT String u Identity Command
 commandParser = do
-  command <- listParser expParser
-  optional $ try $ between (many (char ' ') >> char '{') (char '}') (many $ noneOf "}")
-  return command
+  command <- listParser $ try expParser
+  additionalInfo <- additionalInfoParser
+  return $ Command command additionalInfo
 
 commentParser :: ParsecT String u Identity ()
 commentParser = optional $ do
@@ -107,8 +167,8 @@ commentParser = optional $ do
 packageParser :: ParsecT String u Identity Package
 packageParser = do
   name <- stringParser
-  optional $ try $ between (many (char ' ') >> string "{") (char '}') (many $ noneOf "}")
-  return name
+  additionalInfo <- additionalInfoParser
+  return $ Package name additionalInfo
 
 listParser :: ParsecT String u Identity t -> ParsecT String u Identity [t]
 listParser valueParser =
@@ -116,9 +176,9 @@ listParser valueParser =
     valueParser `sepBy` sep
   where
     startPadding = sep
-    endPadding = optional $ oneOf " \n"
+    endPadding = whiteSpace
     sep = (whiteSpace >> commentParser) <|> whiteSpace
-    whiteSpace = (optional $ many $ oneOf " \n")
+    whiteSpace = optional $ many $ oneOf " \n"
 
 main :: IO ()
 main = do
@@ -128,8 +188,11 @@ main = do
     <*> pure Nothing
     <*> pure Nothing
     <*> pure Nothing
+    <*> pure Nothing
+    <*> pure Nothing
+    <*> pure Nothing
 
   getContents >>= \s -> case parse opamFile "(unknown)" s of
-    Left e -> putStrLn $ show e
+    Left e -> print e
     Right fs -> putStrLn $ opam2nix $ evaluateFields initialOPAM fs
-    -- Right fs -> print fs
+    -- Right fs -> mapM_ print fs
diff --git a/nix/sources.json b/nix/sources.json
index 08be60b04..48ba70104 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -1,4 +1,16 @@
 {
+    "UnionFind": {
+        "branch": "master",
+        "description": "Some variant implementations of the Union-Find algorithm",
+        "homepage": null,
+        "owner": "rinderknecht",
+        "repo": "UnionFind",
+        "rev": "97fdfa78a830e74fd3736e433152b662796840be",
+        "sha256": "0grsrv03x7r5azdcbcbsfdxq7myqnpr4wjgn14faxhnspkigcl9x",
+        "type": "tarball",
+        "url": "https://github.com/rinderknecht/UnionFind/archive/97fdfa78a830e74fd3736e433152b662796840be.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
     "bigstring": {
         "branch": "master",
         "description": "Overlay over bigarrays of chars",
@@ -107,6 +119,18 @@
         "url": "https://github.com/stedolan/ocaml-afl-persistent/archive/a37c4f581ba417d7e09a6efb34fdd8a90a7e9ede.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
+    "opam-repository": {
+        "branch": "master",
+        "description": "Main public package repository for OPAM, the source package manager of OCaml.",
+        "homepage": "https://opam.ocaml.org",
+        "owner": "ocaml",
+        "repo": "opam-repository",
+        "rev": "d67e70b40203a6a1c77ccb2edbe136c1509a73a3",
+        "sha256": "1yphw9xcss284p51qnml5jvfs4mhjcjgdka3wk25q0437zdzqj4n",
+        "type": "tarball",
+        "url": "https://github.com/ocaml/opam-repository/archive/d67e70b40203a6a1c77ccb2edbe136c1509a73a3.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
     "resto": {
         "ref": "master",
         "repo": "https://gitlab.com/nomadic-labs/resto",
@@ -137,6 +161,12 @@
         "rev": "be706b7060cc9805d66fce1a032a586d09ee8718",
         "type": "git"
     },
+    "tezos-opam-repository": {
+        "ref": "master",
+        "repo": "https://gitlab.com/ligolang/tezos-opam-repository",
+        "rev": "dfc46bd895b070bd89028a7ad98741d05ec684df",
+        "type": "git"
+    },
     "uecc": {
         "ref": "master",
         "repo": "https://gitlab.com/nomadic-labs/ocaml-uecc",