* After parsing, compute level/displacement pairs for each variable

  use site, allowing environments to be stores as vectors of values
  rather than maps.  This should speed up evaluation and reduce the
  number of allocations.

1 files changed, 8 insertions, 8 deletions

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index eda081261..a24b7345e 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -18,13 +18,6 @@ struct Value;
 typedef std::map<Symbol, Value> Bindings;
 
 
-struct Env
-{
-    Env * up;
-    Bindings bindings;
-};
-
-
 typedef enum {
     tInt = 1,
     tBool,
@@ -109,6 +102,13 @@ struct Value
 };
 
 
+struct Env
+{
+    Env * up;
+    Value values[0];
+};
+
+
 static inline void mkInt(Value & v, int n)
 {
     v.type = tInt;
@@ -258,7 +258,7 @@ public:
     
     /* Allocation primitives. */
     Value * allocValues(unsigned int count);
-    Env & allocEnv();
+    Env & allocEnv(unsigned int size);
 
     void mkList(Value & v, unsigned int length);
     void mkAttrs(Value & v);