1 files changed, 37 insertions, 3 deletions
diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh
index c06b5a6d1153..62bdd9281f08 100644
--- a/src/libexpr/value.hh
+++ b/src/libexpr/value.hh
@@ -12,7 +12,9 @@ typedef enum {
     tPath,
     tNull,
     tAttrs,
-    tList,
+    tList1,
+    tList2,
+    tListN,
     tThunk,
     tApp,
     tLambda,
@@ -20,6 +22,7 @@ typedef enum {
     tPrimOp,
     tPrimOpApp,
     tExternal,
+    tFloat
 } ValueType;
 
 
@@ -36,6 +39,7 @@ class XMLWriter;
 
 
 typedef long NixInt;
+typedef float NixFloat;
 
 /* External values must descend from ExternalValueBase, so that
  * type-agnostic nix functions (e.g. showType) can be implemented
@@ -119,9 +123,10 @@ struct Value
         const char * path;
         Bindings * attrs;
         struct {
-            unsigned int length;
+            unsigned int size;
             Value * * elems;
-        } list;
+        } bigList;
+        Value * smallList[2];
         struct {
             Env * env;
             Expr * expr;
@@ -138,7 +143,28 @@ struct Value
             Value * left, * right;
         } primOpApp;
         ExternalValueBase * external;
+        NixFloat fpoint;
     };
+
+    bool isList() const
+    {
+        return type == tList1 || type == tList2 || type == tListN;
+    }
+
+    Value * * listElems()
+    {
+        return type == tList1 || type == tList2 ? smallList : bigList.elems;
+    }
+
+    const Value * const * listElems() const
+    {
+        return type == tList1 || type == tList2 ? smallList : bigList.elems;
+    }
+
+    unsigned int listSize() const
+    {
+        return type == tList1 ? 1 : type == tList2 ? 2 : bigList.size;
+    }
 };
 
 
@@ -158,6 +184,14 @@ static inline void mkInt(Value & v, NixInt n)
 }
 
 
+static inline void mkFloat(Value & v, NixFloat n)
+{
+    clearValue(v);
+    v.type = tFloat;
+    v.fpoint = n;
+}
+
+
 static inline void mkBool(Value & v, bool b)
 {
     clearValue(v);