Fixed issue #13

src/libexpr/eval.hh

@@ -63,6 +63,8 @@ typedef std::list<SearchPathElem> SearchPath;
 /* Initialise the Boehm GC, if applicable. */
 void initGC();
 
+typedef std::vector<std::pair<std::string, std::string>> RegistryOverrides;
+
 
 class EvalState
 {
@@ -89,6 +91,9 @@ public:
 
     const ref<Store> store;
 
+    RegistryOverrides registryOverrides;
+
+
 private:
     SrcToStore srcToStore;
 
@@ -211,6 +216,8 @@ public:
        path.  Nothing is copied to the store. */
     Path coerceToPath(const Pos & pos, Value & v, PathSet & context);
 
+    void addRegistryOverrides(RegistryOverrides overrides) { registryOverrides = overrides; }
+
 public:
 
     /* The base environment, containing the builtin functions and