diff --git a/configure.ac b/configure.ac
index 06054cf00c..54db203171 100644
--- a/configure.ac
+++ b/configure.ac
@@ -33,6 +33,7 @@ AC_CONFIG_FILES([Makefile
    src/nix/Makefile
    src/nix-hash/Makefile
    src/fix/Makefile
+   src/fix-ng/Makefile
    scripts/Makefile
    corepkgs/Makefile
    corepkgs/fetchurl/Makefile
diff --git a/src/Makefile.am b/src/Makefile.am
index 200ea45fb0..57af4dbc8f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1 +1 @@
-SUBDIRS = boost libnix libmain nix nix-hash fix
+SUBDIRS = boost libnix libmain nix nix-hash fix fix-ng
diff --git a/src/fix-ng/Makefile.am b/src/fix-ng/Makefile.am
new file mode 100644
index 0000000000..64e8b2ed3a
--- /dev/null
+++ b/src/fix-ng/Makefile.am
@@ -0,0 +1,8 @@
+bin_PROGRAMS = fix-ng
+
+fix_ng_SOURCES = fix.cc
+fix_ng_LDADD = ../libmain/libmain.a ../libnix/libnix.a ../boost/format/libformat.a \
+ -L../../externals/inst/lib -ldb_cxx -lATerm
+
+AM_CXXFLAGS = \
+ -I.. -I../../externals/inst/include -I../libnix -I../libmain
diff --git a/src/fix-ng/fix.cc b/src/fix-ng/fix.cc
new file mode 100644
index 0000000000..9a8ff15130
--- /dev/null
+++ b/src/fix-ng/fix.cc
@@ -0,0 +1,488 @@
+#include <map>
+#include <iostream>
+
+#include "globals.hh"
+#include "normalise.hh"
+#include "shared.hh"
+
+
+typedef ATerm Expr;
+
+typedef map<ATerm, ATerm> NormalForms;
+typedef map<Path, PathSet> PkgPaths;
+typedef map<Path, Hash> PkgHashes;
+
+struct EvalState 
+{
+    Paths searchDirs;
+    NormalForms normalForms;
+    PkgPaths pkgPaths;
+    PkgHashes pkgHashes; /* normalised package hashes */
+    Expr blackHole;
+
+    EvalState()
+    {
+        blackHole = ATmake("BlackHole()");
+        if (!blackHole) throw Error("cannot build black hole");
+    }
+};
+
+
+static Expr evalFile(EvalState & state, const Path & path);
+static Expr evalExpr(EvalState & state, Expr e);
+
+
+static Path searchPath(const Paths & searchDirs, const Path & relPath)
+{
+    if (string(relPath, 0, 1) == "/") return relPath;
+
+    for (Paths::const_iterator i = searchDirs.begin();
+         i != searchDirs.end(); i++)
+    {
+        Path path = *i + "/" + relPath;
+        if (pathExists(path)) return path;
+    }
+
+    throw Error(
+        format("path `%1%' not found in any of the search directories")
+        % relPath);
+}
+
+
+static Expr substExpr(string x, Expr rep, Expr e)
+{
+    char * s;
+    Expr e2;
+
+    if (ATmatch(e, "Var(<str>)", &s))
+        if (x == s)
+            return rep;
+        else
+            return e;
+
+    ATermList formals;
+    if (ATmatch(e, "Function([<list>], <term>)", &formals, &e2)) {
+        while (!ATisEmpty(formals)) {
+            if (!ATmatch(ATgetFirst(formals), "<str>", &s))
+                throw badTerm("not a list of formals", (ATerm) formals);
+            if (x == (string) s)
+                return e;
+            formals = ATgetNext(formals);
+        }
+    }
+
+    /* Generically substitute in subterms. */
+
+    if (ATgetType(e) == AT_APPL) {
+        AFun fun = ATgetAFun(e);
+        int arity = ATgetArity(fun);
+        ATermList args = ATempty;
+
+        for (int i = arity - 1; i >= 0; i--)
+            args = ATinsert(args, substExpr(x, rep, ATgetArgument(e, i)));
+        
+        return (ATerm) ATmakeApplList(fun, args);
+    }
+
+    if (ATgetType(e) == AT_LIST) {
+        ATermList in = (ATermList) e;
+        ATermList out = ATempty;
+
+        while (!ATisEmpty(in)) {
+            out = ATinsert(out, substExpr(x, rep, ATgetFirst(in)));
+            in = ATgetNext(in);
+        }
+
+        return (ATerm) ATreverse(out);
+    }
+
+    throw badTerm("do not know how to substitute", e);
+}
+
+
+static Expr substExprMany(ATermList formals, ATermList args, Expr body)
+{
+    char * s;
+    Expr e;
+
+    /* !!! check args against formals */
+
+    while (!ATisEmpty(args)) {
+        ATerm tup = ATgetFirst(args);
+        if (!ATmatch(tup, "(<str>, <term>)", &s, &e))
+            throw badTerm("expected an argument tuple", tup);
+
+        body = substExpr(s, e, body);
+
+        args = ATgetNext(args);
+    }
+    
+    return body;
+}
+
+
+static PathSet nixExprRootsCached(EvalState & state, const Path & nePath)
+{
+    PkgPaths::iterator i = state.pkgPaths.find(nePath);
+    if (i != state.pkgPaths.end())
+        return i->second;
+    else {
+        PathSet paths = nixExprRoots(nePath);
+        state.pkgPaths[nePath] = paths;
+        return paths;
+    }
+}
+
+
+static Hash hashPackage(EvalState & state, NixExpr ne)
+{
+    if (ne.type == NixExpr::neDerivation) {
+	PathSet inputs2;
+        for (PathSet::iterator i = ne.derivation.inputs.begin();
+             i != ne.derivation.inputs.end(); i++)
+        {
+            PkgHashes::iterator j = state.pkgHashes.find(*i);
+            if (j == state.pkgHashes.end())
+                throw Error(format("don't know expression `%1%'") % (string) *i);
+            inputs2.insert(j->second);
+        }
+	ne.derivation.inputs = inputs2;
+    }
+    return hashTerm(unparseNixExpr(ne));
+}
+
+
+static string processBinding(EvalState & state, Expr e, NixExpr & ne)
+{
+    char * s1;
+
+    if (ATmatch(e, "NixExpr(<str>)", &s1)) {
+        Path nePath(s1);
+        PathSet paths = nixExprRootsCached(state, nePath);
+        if (paths.size() != 1) abort();
+        Path path = *(paths.begin());
+        ne.derivation.inputs.insert(nePath);
+        return path;
+    }
+    
+    if (ATmatch(e, "<str>", &s1))
+        return s1;
+
+    if (ATmatch(e, "True")) return "1";
+    
+    if (ATmatch(e, "False")) return "";
+
+    ATermList l;
+    if (ATmatch(e, "[<list>]", &l)) {
+	string s;
+	bool first = true;
+        while (!ATisEmpty(l)) {
+	    if (!first) s = s + " "; else first = false;
+	    s += processBinding(state, evalExpr(state, ATgetFirst(l)), ne);
+            l = ATgetNext(l);
+        }
+	return s;
+    }
+    
+    throw badTerm("invalid package binding", e);
+}
+
+
+static Expr evalExpr2(EvalState & state, Expr e)
+{
+    char * s1;
+    Expr e1, e2, e3, e4;
+    ATermList bnds;
+
+    /* Normal forms. */
+    if (ATmatch(e, "<str>", &s1) ||
+        ATmatch(e, "[<list>]", &e1) ||
+        ATmatch(e, "True") ||
+        ATmatch(e, "False") ||
+        ATmatch(e, "Function([<list>], <term>)", &e1, &e2) ||
+        ATmatch(e, "NixExpr(<str>)", &s1))
+        return e;
+
+    try {
+        Hash pkgHash = hashPackage(state, parseNixExpr(e));
+        Path pkgPath = writeTerm(e, "");
+        state.pkgHashes[pkgPath] = pkgHash;
+        return ATmake("NixExpr(<str>)", pkgPath.c_str());
+    } catch (...) { /* !!! catch parse errors only */
+    }
+
+    /* Application. */
+    if (ATmatch(e, "Call(<term>, [<list>])", &e1, &e2) ||
+        ATmatch(e, "App(<term>, [<list>])", &e1, &e2)) {
+        e1 = evalExpr(state, e1);
+        if (!ATmatch(e1, "Function([<list>], <term>)", &e3, &e4))
+            throw badTerm("expecting a function", e1);
+        return evalExpr(state,
+            substExprMany((ATermList) e3, (ATermList) e2, e4));
+    }
+
+    /* Conditional. */
+    if (ATmatch(e, "If(<term>, <term>, <term>)", &e1, &e2, &e3)) {
+        e1 = evalExpr(state, e1);
+        Expr x;
+        if (ATmatch(e1, "True")) x = e2;
+        else if (ATmatch(e1, "False")) x = e3;
+        else throw badTerm("expecting a boolean", e1);
+        return evalExpr(state, x);
+    }
+
+    /* Ad-hoc function for string matching. */
+    if (ATmatch(e, "HasSubstr(<term>, <term>)", &e1, &e2)) {
+        e1 = evalExpr(state, e1);
+        e2 = evalExpr(state, e2);
+        
+        char * s1, * s2;
+        if (!ATmatch(e1, "<str>", &s1))
+            throw badTerm("expecting a string", e1);
+        if (!ATmatch(e2, "<str>", &s2))
+            throw badTerm("expecting a string", e2);
+        
+        return
+            string(s1).find(string(s2)) != string::npos ?
+            ATmake("True") : ATmake("False");
+    }
+
+    /* Platform constant. */
+    if (ATmatch(e, "Platform")) {
+        return ATmake("<str>", thisSystem.c_str());
+    }
+
+    /* Fix inclusion. */
+    if (ATmatch(e, "IncludeFix(<str>)", &s1)) {
+        Path fileName(s1);
+        return evalFile(state, s1);
+    }
+
+    /* Relative files. */
+    if (ATmatch(e, "Relative(<str>)", &s1)) {
+        Path srcPath = searchPath(state.searchDirs, s1);
+        Path dstPath = addToStore(srcPath);
+
+        ClosureElem elem;
+        NixExpr ne;
+        ne.type = NixExpr::neClosure;
+        ne.closure.roots.insert(dstPath);
+        ne.closure.elems[dstPath] = elem;
+
+        Hash pkgHash = hashPackage(state, ne);
+        Path pkgPath = writeTerm(unparseNixExpr(ne), "");
+        state.pkgHashes[pkgPath] = pkgHash;
+
+        msg(lvlChatty, format("copied `%1%' -> closure `%2%'")
+            % srcPath % pkgPath);
+
+        return ATmake("NixExpr(<str>)", pkgPath.c_str());
+    }
+
+    /* Packages are transformed into Nix derivation expressions. */
+    if (ATmatch(e, "Package([<list>])", &bnds)) {
+
+        /* Evaluate the bindings and put them in a map. */
+        map<string, ATerm> bndMap;
+        bndMap["platform"] = ATmake("<str>", thisSystem.c_str());
+        while (!ATisEmpty(bnds)) {
+            ATerm bnd = ATgetFirst(bnds);
+            if (!ATmatch(bnd, "(<str>, <term>)", &s1, &e1))
+                throw badTerm("binding expected", bnd);
+            bndMap[s1] = evalExpr(state, e1);
+            bnds = ATgetNext(bnds);
+        }
+
+        /* Gather information for building the derivation
+           expression. */
+        NixExpr ne;
+        ne.type = NixExpr::neDerivation;
+        ne.derivation.platform = thisSystem;
+        string name;
+        Path outPath;
+        Hash outHash;
+        bool outHashGiven = false;
+        bnds = ATempty;
+
+        for (map<string, ATerm>::iterator it = bndMap.begin();
+             it != bndMap.end(); it++)
+        {
+            string key = it->first;
+            ATerm value = it->second;
+
+            if (key == "args") {
+                ATermList args;
+                if (!ATmatch(value, "[<list>]", &args))
+                    throw badTerm("list expected", value);
+                
+                while (!ATisEmpty(args)) {
+                    Expr arg = evalExpr(state, ATgetFirst(args));
+                    ne.derivation.args.push_back(processBinding(state, arg, ne));
+                    args = ATgetNext(args);
+                }
+            }
+
+            else {
+                string s = processBinding(state, value, ne);
+                ne.derivation.env[key] = s;
+
+                if (key == "build") ne.derivation.builder = s;
+                if (key == "name") name = s;
+                if (key == "outPath") outPath = s;
+                if (key == "id") { 
+                    outHash = parseHash(s);
+                    outHashGiven = true;
+                }
+            }
+
+            bnds = ATinsert(bnds, 
+                ATmake("(<str>, <term>)", key.c_str(), value));
+        }
+
+        if (ne.derivation.builder == "")
+            throw badTerm("no builder specified", e);
+        
+        if (name == "")
+            throw badTerm("no package name specified", e);
+        
+        /* Determine the output path. */
+        if (!outHashGiven) outHash = hashPackage(state, ne);
+        if (outPath == "")
+            /* Hash the Nix expression with no outputs to produce a
+               unique but deterministic path name for this package. */
+            outPath = 
+                canonPath(nixStore + "/" + ((string) outHash).c_str() + "-" + name);
+        ne.derivation.env["out"] = outPath;
+        ne.derivation.outputs.insert(outPath);
+
+        /* Write the resulting term into the Nix store directory. */
+        Hash pkgHash = outHashGiven
+            ? hashString((string) outHash + outPath)
+            : hashPackage(state, ne);
+        Path pkgPath = writeTerm(unparseNixExpr(ne), "-d-" + name);
+        state.pkgHashes[pkgPath] = pkgHash;
+
+        msg(lvlChatty, format("instantiated `%1%' -> `%2%'")
+            % name % pkgPath);
+
+        return ATmake("NixExpr(<str>)", pkgPath.c_str());
+    }
+
+    /* BaseName primitive function. */
+    if (ATmatch(e, "BaseName(<term>)", &e1)) {
+        e1 = evalExpr(state, e1);
+        if (!ATmatch(e1, "<str>", &s1)) 
+            throw badTerm("string expected", e1);
+        return ATmake("<str>", baseNameOf(s1).c_str());
+    }
+
+    /* Barf. */
+    throw badTerm("invalid expression", e);
+}
+
+
+static Expr evalExpr(EvalState & state, Expr e)
+{
+    Nest nest(lvlVomit, format("evaluating expression: %1%") % printTerm(e));
+
+    /* Consult the memo table to quickly get the normal form of
+       previously evaluated expressions. */
+    NormalForms::iterator i = state.normalForms.find(e);
+    if (i != state.normalForms.end()) {
+        if (i->second == state.blackHole)
+            throw badTerm("infinite recursion", e);
+        return i->second;
+    }
+
+    /* Otherwise, evaluate and memoize. */
+    state.normalForms[e] = state.blackHole;
+    Expr nf = evalExpr2(state, e);
+    state.normalForms[e] = nf;
+    return nf;
+}
+
+
+static Expr evalFile(EvalState & state, const Path & relPath)
+{
+    Path path = searchPath(state.searchDirs, relPath);
+    Nest nest(lvlTalkative, format("evaluating file `%1%'") % path);
+    Expr e = ATreadFromNamedFile(path.c_str());
+    if (!e) 
+        throw Error(format("unable to read a term from `%1%'") % path);
+    return evalExpr(state, e);
+}
+
+
+static Expr evalStdin(EvalState & state)
+{
+    Nest nest(lvlTalkative, format("evaluating standard input"));
+    Expr e = ATreadFromFile(stdin);
+    if (!e) 
+        throw Error(format("unable to read a term from stdin"));
+    return evalExpr(state, e);
+}
+
+
+static void printNixExpr(EvalState & state, Expr e)
+{
+    ATermList es;
+    char * s;
+    if (ATmatch(e, "NixExpr(<str>)", &s)) {
+        cout << format("%1%\n") % s;
+    } 
+    else if (ATmatch(e, "[<list>]", &es)) {
+        while (!ATisEmpty(es)) {
+            printNixExpr(state, evalExpr(state, ATgetFirst(es)));
+            es = ATgetNext(es);
+        }
+    }
+    else throw badTerm("top level does not evaluate to a (list of) Nix expression(s)", e);
+}
+
+
+void run(Strings args)
+{
+    EvalState state;
+    Strings files;
+    bool readStdin = false;
+
+    state.searchDirs.push_back(".");
+    state.searchDirs.push_back(nixDataDir + "/fix");
+    
+    for (Strings::iterator it = args.begin();
+         it != args.end(); )
+    {
+        string arg = *it++;
+
+        if (arg == "--includedir" || arg == "-I") {
+            if (it == args.end())
+                throw UsageError(format("argument required in `%1%'") % arg);
+            state.searchDirs.push_back(*it++);
+        }
+        else if (arg == "--verbose" || arg == "-v")
+            verbosity = (Verbosity) ((int) verbosity + 1);
+        else if (arg == "-")
+            readStdin = true;
+        else if (arg[0] == '-')
+            throw UsageError(format("unknown flag `%1%`") % arg);
+        else
+            files.push_back(arg);
+    }
+
+    openDB();
+
+    if (readStdin) {
+        Expr e = evalStdin(state);
+        printNixExpr(state, e);
+    }
+
+    for (Strings::iterator it = files.begin();
+         it != files.end(); it++)
+    {
+        Expr e = evalFile(state, *it);
+        printNixExpr(state, e);
+    }
+}
+
+
+string programId = "fix";