1 files changed, 66 insertions, 0 deletions
diff --git a/src/libnix/expr.hh b/src/libnix/expr.hh
new file mode 100644
index 000000000000..7d0420935f9d
--- /dev/null
+++ b/src/libnix/expr.hh
@@ -0,0 +1,66 @@
+#ifndef __FSTATE_H
+#define __FSTATE_H
+
+extern "C" {
+#include <aterm2.h>
+}
+
+#include "store.hh"
+
+
+/* Abstract syntax of Nix expressions. */
+
+struct ClosureElem
+{
+    PathSet refs;
+};
+
+typedef map<Path, ClosureElem> ClosureElems;
+
+struct Closure
+{
+    PathSet roots;
+    ClosureElems elems;
+};
+
+typedef map<string, string> StringPairs;
+
+struct Derivation
+{
+    PathSet outputs;
+    PathSet inputs; /* Nix expressions, not actual inputs */
+    string platform;
+    Path builder;
+    Strings args;
+    StringPairs env;
+};
+
+struct NixExpr
+{
+    enum { neClosure, neDerivation } type;
+    Closure closure;
+    Derivation derivation;
+};
+
+
+/* Return a canonical textual representation of an expression. */
+string printTerm(ATerm t);
+
+/* Throw an exception with an error message containing the given
+   aterm. */
+Error badTerm(const format & f, ATerm t);
+
+/* Hash an aterm. */
+Hash hashTerm(ATerm t);
+
+/* Write an aterm to the Nix store directory, and return its path. */
+Path writeTerm(ATerm t, const string & suffix);
+
+/* Parse a Nix expression. */
+NixExpr parseNixExpr(ATerm t);
+
+/* Parse a Nix expression. */
+ATerm unparseNixExpr(const NixExpr & ne);
+
+
+#endif /* !__FSTATE_H */