wren_value.h.diff

diff --git a/src/vm/wren_value.h b/src/vm/wren_value.h
index bdc6ed1..b32a815 100644
--- a/src/vm/wren_value.h
+++ b/src/vm/wren_value.h
@@ -106,14 +106,14 @@ typedef struct sObjClass ObjClass;
 typedef struct sObj Obj;
 struct sObj
 {
-  ObjType type;
-  bool isDark;
-
   // The object's class.
   ObjClass* classObj;
 
   // The next object in the linked list of all currently allocated objects.
   struct sObj* next;
+
+  unsigned char isDark  : 4;
+  ObjType type : 4;
 };
 
 #if WREN_NAN_TAGGING
@@ -253,15 +253,15 @@ typedef struct
   ObjModule* module;
 
   // The maximum number of stack slots this function may use.
-  int maxSlots;
+  uint16_t maxSlots;
   
   // The number of upvalues this function closes over.
-  int numUpvalues;
+  uint16_t numUpvalues;
   
   // The number of parameters this function expects. Used to ensure that .call
   // handles a mismatch between number of parameters and arguments. This will
   // only be set for fns, and not ObjFns that represent methods or scripts.
-  int arity;
+  uint8_t arity;
   FnDebug* debug;
 } ObjFn;
 
@@ -324,17 +324,17 @@ typedef struct sObjFiber
   Value* stackTop;
   
   // The number of allocated slots in the stack array.
-  int stackCapacity;
+  uint16_t stackCapacity;
   
   // The stack of call frames. This is a dynamic array that grows as needed but
   // never shrinks.
   CallFrame* frames;
   
   // The number of frames currently in use in [frames].
-  int numFrames;
+  uint16_t numFrames;
   
   // The number of [frames] allocated.
-  int frameCapacity;
+  uint16_t frameCapacity;
   
   // Pointer to the first node in the linked list of open upvalues that are
   // pointing to values still on the stack. The head of the list will be the
@@ -349,7 +349,7 @@ typedef struct sObjFiber
   // error object. Otherwise, it will be null.
   Value error;
   
-  FiberState state;
+  FiberState state:2;
 } ObjFiber;
 
 typedef enum
@@ -370,7 +370,7 @@ typedef enum
 
 typedef struct
 {
-  MethodType type;
+  MethodType type:4;
 
   // The method function itself. The [type] determines which field of the union
   // is used.
@@ -391,7 +391,7 @@ struct sObjClass
 
   // The number of fields needed for an instance of this class, including all
   // of its superclass fields.
-  int numFields;
+  int16_t numFields;
 
   // The table of methods that are defined in or inherited by this class.
   // Methods are called by symbol, and the symbol directly maps to an index in
@@ -460,10 +460,10 @@ typedef struct
   Obj obj;
 
   // The number of entries allocated.
-  uint32_t capacity;
+  uint16_t capacity;
 
   // The number of entries in the map.
-  uint32_t count;
+  uint16_t count;
 
   // Pointer to a contiguous array of [capacity] entries.
   MapEntry* entries;

Actually, in line 32, the type of numUpValues can be uint8_t, as shown here