Remove capability of rebinding lexical constants (fixes #46)

sorear · Nov 5, 2011 · ccb1914 · ccb1914
1 parent eb2bc3c
commit ccb1914
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Showing 3 changed files with 24 additions and 23 deletions.
diff --git a/lib/CodeGen.cs b/lib/CodeGen.cs
@@ -3734,8 +3734,8 @@ public class DowncallReceiver : CallReceiver {
                 string   cn = (string)args[2];
                 while (si != null && !si.dylex.ContainsKey(cn)) si = si.outer;
                 LexInfo li = si == null ? null : si.dylex[cn];
-                if (li is LIHint) {
-                    ((LIHint)li).var.v = v;
+                if (li is LIConstant) {
+                    ((LIConstant)li).value = v;
                 } else if (li is LICommon) {
                     StashEnt hkey = Kernel.currentGlobals[((LICommon)li).hkey];
                     hkey.constant = true;
@@ -3858,7 +3858,7 @@ public class DowncallReceiver : CallReceiver {
                 var llab   = li as LILabel;
                 if (llab != null)
                     r = new object[] { "label",null,null,null };
-                var lhint  = li as LIHint;
+                var lhint  = li as LIConstant;
                 if (lhint != null)
                     r = new object[] { "hint",null,null,null };
                 var lcomm  = li as LICommon;
@@ -4186,7 +4186,7 @@ public class DowncallReceiver : CallReceiver {
 
                 return AddLexical(args, new LISimple(flags, type));
             } else if (cmd == "add_hint") {
-                return AddLexical(args, new LIHint());
+                return AddLexical(args, new LIConstant());
             } else if (cmd == "add_label") {
                 return AddLexical(args, new LILabel());
             } else if (cmd == "add_dispatcher") {

diff --git a/lib/Kernel.cs b/lib/Kernel.cs
@@ -1091,7 +1091,7 @@ public abstract class LexInfo {
 
         internal abstract void DoFreeze(FreezeBuffer fb);
         internal enum LexSerCode {
-            Simple, Sub, Label, Dispatch, Common, Hint, Package, Alias
+            Simple, Sub, Label, Dispatch, Common, Constant, Package, Alias
         }
     }
 
@@ -1170,32 +1170,33 @@ public class LICommon : LexInfo {
         }
     }
 
-    public class LIHint : LexInfo {
-        public StashEnt var;
-        public LIHint() { }
-        public LIHint(StashEnt var) { this.var = var; }
+    public class LIConstant : LexInfo {
+        public Variable value;
+        public LIConstant() { this.value = Kernel.AnyMO.typeVar; }
+        internal LIConstant(Variable value) { this.value = value; }
         public override void Init(Frame f) { }
-        public override void BindFields() {
-            var = new StashEnt();
-        }
+        public override void BindFields() { }
 
-        public override object Get(Frame f) { return var.v; }
-        public override void Set(Frame f, object to) { var.v = (Variable)to; }
+        public override object Get(Frame f) { return value; }
+        public override void Set(Frame f, object to) {
+            throw new NieczaException("Cannot bind to constant " + name);
+        }
 
         internal override ClrOp GetCode(int up) {
-            return new ClrGetField(Tokens.StashEnt_v,
-                EmitUnit.Current.RefConstant(name, "E", var, null).head);
+            return EmitUnit.Current.RefConstant(name, "", value, typeof(Variable)).head;
         }
 
         // XXX should die() with constant improvements
         internal override ClrOp SetCode(int up, ClrOp to) {
-            return new ClrSetField(Tokens.StashEnt_v,
-                EmitUnit.Current.RefConstant(name, "E", var, null).head, to);
+            return new ClrOperator(Tokens.Void, OpCodes.Throw, new [] {
+                new ClrConstructorCall(typeof(NieczaException).
+                    GetConstructor(new [] { typeof(string) }),
+                    new [] { new ClrStringLiteral("Cannot bind to constant " + name) }) });
         }
 
         internal override void DoFreeze(FreezeBuffer fb) {
-            fb.Byte((byte)LexSerCode.Hint);
-            fb.ObjRef(var);
+            fb.Byte((byte)LexSerCode.Constant);
+            fb.ObjRef(value);
         }
     }
 
@@ -2101,8 +2102,8 @@ public class UsedInScopeInfo {
                     case (int) LexInfo.LexSerCode.Common:
                         li = new LICommon(tb.String());
                         break;
-                    case (int) LexInfo.LexSerCode.Hint:
-                        li = new LIHint((StashEnt) tb.ObjRef());
+                    case (int) LexInfo.LexSerCode.Constant:
+                        li = new LIConstant((Variable) tb.ObjRef());
                         break;
                     case (int) LexInfo.LexSerCode.Package:
                         li = new LIPackage((STable) tb.ObjRef());

diff --git a/lib/Serialize.cs b/lib/Serialize.cs
@@ -64,7 +64,7 @@ struct ObjRef {
         internal static HashAlgorithm NewHash() { return new SHA256Managed(); }
 
         static readonly string signature = "Niecza-Serialized-Module";
-        static readonly int version = 5;
+        static readonly int version = 6;
 
         // Routines for use by serialization code
         public bool CheckWriteObject(SerUnit into, object o,