Open certain data structures to allow GC walking from roots to all reachable values

csharp/NShovel/Shovel/Api.cs

@@ -26,6 +26,8 @@
 using System.Linq;
 using System.Security.Cryptography;
 using Shovel.Exceptions;
+using Shovel.Vm.Types;
+using Shovel.Vm;
 
 namespace Shovel
 {
@@ -214,6 +216,14 @@ public static Value CheckStackTop (Vm.Vm vm)
             return vm.CheckStackTop ();
         }
 
+        public static IEnumerable<Value> GetUsedStack( Vm.Vm vm ) {
+            return vm.GetUsedStack();
+        }
+
+        public static VmEnvironment GetCurrentEnvironment( Vm.Vm vm ) { 
+            return vm.GetCurrentEnvironment(); 
+        }
+
         public static void WakeUpVm (Vm.Vm vm)
         {
             vm.WakeUp ();
@@ -253,7 +263,7 @@ public static Value GetStructInstanceValue(StructInstance str, string key, Value
         {
             for (int i = 0; i < str.Struct.Fields.Length; i++) {
                 if (str.Struct.Fields[i] == key) {
-                    return str.Values[i];
+                    return str.values[i];
                 }
             }
             return defaultValue;
@@ -263,7 +273,7 @@ public static bool SetStructInstanceValue(StructInstance str, string key, Value
         {
             for (int i = 0; i < str.Struct.Fields.Length; i++) {
                 if (str.Struct.Fields[i] == key) {
-                    str.Values[i] = newValue;
+                    str.values[i] = newValue;
                     return true;
                 }
             }

csharp/NShovel/Shovel/Callable.cs

@@ -41,7 +41,7 @@ public class Callable
         // The next two fields are only used if this is a ShovelScript closure.
         internal int? ProgramCounter { get; set; }
 
-        internal Vm.Types.VmEnvironment Environment { get; set; }
+        public Vm.VmEnvironment Environment { get; internal set; }
 
         internal Func<VmApi, Value[], int, int, Value> RequiredPrimitive { get; set; }
 
@@ -95,8 +95,6 @@ internal static Func<VmApi, Value[], int, int, Value> MakeHostCallable (
             Func<VmApi, Value, Value, Value, Value> callable)
         {
             return (vmapi, args, start, length) => callable (vmapi, args [start], args [start + 1], args [start + 2]);
-        }
-
+        }
     }
-}
-
+}

csharp/NShovel/Shovel/Serialization/VmStateSerializer.cs

@@ -24,7 +24,8 @@
 using System.IO;
 using Shovel.Vm.Types;
 using System.Text;
-using System.Linq;
+using System.Linq;
+using Shovel.Vm;
 
 namespace Shovel.Serialization
 {
@@ -433,8 +434,8 @@ VmEnvFrame RebuildEnvFrame (
             var result = new VmEnvFrame ();
             objects [index] = result;
 
-            result.VarNames = (string[])reader (composite.Elements [0]);
-            result.Values = (Value[])reader (composite.Elements [1]);
+            result.VarNamesInternal = (string[])reader (composite.Elements [0]);
+            result.ValuesInernal = (Value[])reader (composite.Elements [1]);
             result.IntroducedAtProgramCounter = (int)(long)reader (composite.Elements [2]);
 
             return result;
@@ -457,7 +458,7 @@ StructInstance RebuildStructInstance (
             objects [index] = result;
 
             result.Struct = (Struct)reader (composite.Elements [0]);
-            result.Values = (Value[])reader (composite.Elements [1]);
+            result.values = (Value[])reader (composite.Elements [1]);
 
             return result;
         }
@@ -670,8 +671,8 @@ int SerializeEnvFrame (VmEnvFrame frame, object obj)
                 Elements = new int[3] 
             };
             var result = SerializeOneHashed (composite, obj);
-            composite.Elements [0] = Serialize (frame.VarNames);
-            composite.Elements [1] = Serialize (frame.Values);
+            composite.Elements [0] = Serialize (frame.VarNamesInternal);
+            composite.Elements [1] = Serialize (frame.ValuesInernal);
             composite.Elements [2] = SerializeOne (frame.IntroducedAtProgramCounter);
             return result;
         }
@@ -695,7 +696,7 @@ int SerializeStructInstance (StructInstance structInstance, object obj)
             };
             var result = SerializeOneHashed (composite, obj);
             composite.Elements [0] = Serialize (structInstance.Struct);
-            composite.Elements [1] = SerializeShovelValueArray (structInstance.Values);
+            composite.Elements [1] = SerializeShovelValueArray (structInstance.values);
             return result;
         }
 
@@ -717,11 +718,11 @@ int SerializeShovelValue (Value sv, object obj)
             case Value.Kinds.Hash:
                 return SerializeHash (sv.hashValue, obj);
             case Value.Kinds.Callable:
-                return SerializeCallable (sv.CallableValue, obj);
+                return SerializeCallable (sv.callableValue, obj);
             case Value.Kinds.ReturnAddress:
-                return SerializeReturnAddress (sv.ReturnAddressValue, obj);
+                return SerializeReturnAddress (sv.returnAddressValue, obj);
             case Value.Kinds.NamedBlock:
-                return SerializeNamedBlock (sv.NamedBlockValue, obj);
+                return SerializeNamedBlock (sv.namedBlockValue, obj);
             case Value.Kinds.Struct:
                 return SerializeStruct (sv.StructValue, obj);
             case Value.Kinds.StructInstance:

csharp/NShovel/Shovel/StructInstance.cs

@@ -1,11 +1,14 @@
 using System;
+using System.Collections.Generic;
 
 namespace Shovel
 {
     public class StructInstance
     {
         internal Struct Struct;
-        internal Value[] Values;
+        internal Value[] values;
+
+        public IEnumerable<Value> Values { get { return values; } }
     }
 }
 

csharp/NShovel/Shovel/Value.cs

@@ -231,17 +231,67 @@ public Either<Dictionary<Value, Value>> Hash
         }
 
         [FieldOffset(8)]
-        internal Callable CallableValue;
+        internal Callable callableValue;
+
+        public Either<Callable> CallableValue {
+            get {
+                if ( Kind == Kinds.Callable ) {
+                    return new Either<Callable>( this.callableValue );
+                }
+                else {
+                    return new Either<Callable>( new ShovelException( "Value is not a callable.", null ) );
+                }
+            }
+        }
+
         [FieldOffset(8)]
-        internal ReturnAddress ReturnAddressValue;
+        internal StructInstance structInstanceValue;
+
+        public Either<StructInstance> StructInstanceValue {
+            get {
+                if ( Kind == Kinds.StructInstance ) {
+                    return new Either<StructInstance>( this.structInstanceValue );
+                }
+                else {
+                    return new Either<StructInstance>( new ShovelException( "Value is not a struct instance.", null ) );
+                }
+            }
+        }
+
+        [FieldOffset( 8 )]
+        internal NamedBlock namedBlockValue;
+
+        public Either<NamedBlock> NamedBlockValue {
+            get {
+                if ( Kind == Kinds.NamedBlock ) {
+                    return new Either<NamedBlock>( this.namedBlockValue );
+                }
+                else {
+                    return new Either<NamedBlock>( new ShovelException( "Value is not a named block.", null ) );
+                }
+            }
+        }
+
         [FieldOffset(8)]
-        internal NamedBlock NamedBlockValue;
+        internal ReturnAddress returnAddressValue;
+
+        public Either<ReturnAddress> ReturnAddressValue {
+            get {
+                if ( Kind == Kinds.ReturnAddress ) {
+                    return new Either<ReturnAddress>( this.returnAddressValue );
+                }
+                else {
+                    return new Either<ReturnAddress>( new ShovelException( "Value is not a return address.", null ) );
+                }
+            }
+        }
+
         [FieldOffset(8)]
-        internal Struct StructValue;
+        internal Struct StructValue;
 
         [FieldOffset(8)]
-        internal StructInstance structInstanceValue;
-
+        internal StructInstance structInstanceValue;
+
         public Either<StructInstance> StructInstance
         {
             get
@@ -341,23 +391,23 @@ internal static Value Make (Callable c)
         {
             Value result = value;
             result.Kind = Kinds.Callable;
-            result.CallableValue = c;
+            result.callableValue = c;
             return result;
         }
 
         internal static Value Make (ReturnAddress ra)
         {
             Value result = value;
             result.Kind = Kinds.ReturnAddress;
-            result.ReturnAddressValue = ra;
+            result.returnAddressValue = ra;
             return result;
         }
 
         internal static Value Make (NamedBlock nb)
         {
             Value result = value;
             result.Kind = Kinds.NamedBlock;
-            result.NamedBlockValue = nb;
+            result.namedBlockValue = nb;
             return result;
         }
 
@@ -383,15 +433,15 @@ public override bool Equals (object obj)
             case Kinds.Hash:
                 return sv.Kind == Kinds.Hash && this.hashValue == sv.hashValue;
             case Kinds.Callable:
-                return sv.Kind == Kinds.Callable && this.CallableValue == sv.CallableValue;
+                return sv.Kind == Kinds.Callable && Equals( this.callableValue, sv.callableValue );
             case Kinds.ReturnAddress:
-                return sv.Kind == Kinds.ReturnAddress && this.ReturnAddressValue == sv.ReturnAddressValue;
+                return sv.Kind == Kinds.ReturnAddress && Equals( this.returnAddressValue, sv.returnAddressValue );
             case Kinds.NamedBlock:
-                return sv.Kind == Kinds.NamedBlock && this.NamedBlockValue == sv.NamedBlockValue;
+                return sv.Kind == Kinds.NamedBlock && Equals( this.namedBlockValue, sv.namedBlockValue );
             case Kinds.Struct:
-                return sv.Kind == Kinds.Struct && this.StructValue == sv.StructValue;
+                return sv.Kind == Kinds.Struct && Equals( this.StructValue, sv.StructValue );
             case Kinds.StructInstance:
-                return sv.Kind == Kinds.StructInstance && this.structInstanceValue == sv.structInstanceValue;
+                return sv.Kind == Kinds.StructInstance && Equals( this.structInstanceValue, sv.structInstanceValue );
             default:
                 Utils.Panic ();
                 throw new InvalidOperationException ();
@@ -416,11 +466,11 @@ public override int GetHashCode ()
             case Kinds.Hash:
                 return this.hashValue.GetHashCode ();
             case Kinds.Callable:
-                return this.CallableValue.GetHashCode ();
+                return this.callableValue.GetHashCode ();
             case Kinds.ReturnAddress:
-                return this.ReturnAddressValue.GetHashCode ();
+                return this.returnAddressValue.GetHashCode ();
             case Kinds.NamedBlock:
-                return this.NamedBlockValue.GetHashCode ();
+                return this.namedBlockValue.GetHashCode ();
             case Kinds.Struct:
                 return this.StructValue.GetHashCode();
             case Kinds.StructInstance:

csharp/NShovel/Shovel/Vm/Prim0.cs

@@ -102,14 +102,14 @@ static Value HashToStruct (VmApi api, Value[] args, int start, int length)
             var ztruct = args [start].StructValue;
             var result = new StructInstance ();
             result.Struct = ztruct;
-            result.Values = new Value[ztruct.Fields.Length];
+            result.values = new Value[ztruct.Fields.Length];
             var hash = args [start + 1].hashValue;
             var sizeIncrease = 1 + ztruct.Fields.Length;
             api.CellsIncrementHerald (sizeIncrease);
             for (int i = 0; i < ztruct.Fields.Length; i++) {
                 var svKey = Value.Make (ztruct.Fields [i]);
                 if (hash.ContainsKey (svKey)) {
-                    result.Values [i] = hash [svKey];
+                    result.values [i] = hash [svKey];
                 }
             }
             api.CellsIncrementer (sizeIncrease);
@@ -127,7 +127,7 @@ static Value StructToHash (VmApi api, Value[] args, int start, int length)
             var sizeIncrease = 1 + 2 * ztruct.Fields.Length;
             api.CellsIncrementHerald (sizeIncrease);
             for (int i = 0; i < ztruct.Fields.Length; i++) {
-                result [Value.Make (ztruct.Fields [i])] = structInstance.Values [i];
+                result [Value.Make (ztruct.Fields [i])] = structInstance.values [i];
             }
             api.CellsIncrementer (sizeIncrease);
             return Value.Make (result);
@@ -146,9 +146,9 @@ static Value InstantiateStruct (VmApi api, Value[] args, int start, int length)
             api.CellsIncrementHerald (sizeIncrease);
             var result = new StructInstance ();
             result.Struct = ztruct;
-            result.Values = new Value[ztruct.Fields.Length];
+            result.values = new Value[ztruct.Fields.Length];
             for (int i = 1; i < length; i++) {
-                result.Values [i - 1] = args [start + i];
+                result.values [i - 1] = args [start + i];
             }
             api.CellsIncrementer (sizeIncrease);
             return Value.Make (result);
@@ -918,12 +918,12 @@ internal static bool HashOrStructGetDot (Vm vm, VmApi api, ref Value obj, ref Va
                 if (cache != null) {
                     var info = (Tuple<Struct, int>)cache;
                     if (info.Item1 == ztruct) {
-                        obj = structInstance.Values [info.Item2];
+                        obj = structInstance.values [info.Item2];
                         return true;
                     }
                 }
                 int location = FindLocationInStruct (api, ztruct, index.stringValue);
-                obj = structInstance.Values [location];
+                obj = structInstance.values [location];
                 vm.SetCurrentCache (Tuple.Create (ztruct, location));
             } else if (obj.Kind == Value.Kinds.Hash) {
                 if (!obj.hashValue.ContainsKey (index)) {
@@ -951,12 +951,12 @@ internal static bool HashOrStructDotSet (
                 if (cache != null) {
                     var info = (Tuple<Struct, int>)cache;
                     if (info.Item1 == ztruct) {
-                        structInstance.Values [info.Item2] = value;
+                        structInstance.values [info.Item2] = value;
                         return true;
                     }
                 }
                 int location = FindLocationInStruct (api, ztruct, index.stringValue);
-                structInstance.Values [location] = value;
+                structInstance.values [location] = value;
                 vm.SetCurrentCache (Tuple.Create (ztruct, location));
             } else if (obj.Kind == Value.Kinds.Hash) {
                 return HashSet(api, ref obj, ref index, ref value);
@@ -1062,12 +1062,12 @@ static void AdjustRealStartEnd (VmApi api, ref int realStart, ref int realEnd, i
 
         static Value SetHandlers(VmApi api, Value arrayOrHash, Value getter, Value setter)
         {
-            if (getter.Kind != Value.Kinds.Null && (getter.Kind != Value.Kinds.Callable || getter.CallableValue.Arity != 2))
+            if (getter.Kind != Value.Kinds.Null && (getter.Kind != Value.Kinds.Callable || getter.callableValue.Arity != 2))
             {
                 api.RaiseShovelError("The second parameter (getter) should be a callable with 2 parameters.");
                 throw new InvalidOperationException();
             }
-            if (setter.Kind != Value.Kinds.Null && (setter.Kind != Value.Kinds.Callable || setter.CallableValue.Arity != 3))
+            if (setter.Kind != Value.Kinds.Null && (setter.Kind != Value.Kinds.Callable || setter.callableValue.Arity != 3))
             {
                 api.RaiseShovelError("The third parameter (setter) should be a callable with 3 parameters.");
                 throw new InvalidOperationException();
@@ -1394,8 +1394,8 @@ private static string ShovelStringRepresentationImpl (
                 var structInstance = obj.structInstanceValue;
                 var ztruct = structInstance.Struct;
                 pieces.Add (StructAsString (ztruct));
-                for (var i = 0; i < structInstance.Values.Length; i++) {
-                    pieces.Add (ShovelStringRepresentationImpl (api, structInstance.Values [i], visited));
+                for (var i = 0; i < structInstance.values.Length; i++) {
+                    pieces.Add (ShovelStringRepresentationImpl (api, structInstance.values [i], visited));
                 }
                 sb.Append (String.Join (", ", pieces));
                 sb.Append (")");

csharp/NShovel/Shovel/Vm/Types/NamedBlock.cs

@@ -24,14 +24,13 @@
 
 namespace Shovel.Vm.Types
 {
-	internal class NamedBlock
-	{
-		internal string Name { get; set; }
+    public class NamedBlock
+    {
+        internal string Name { get; set; }
 
-		internal int BlockEnd { get; set; }
-
-		internal VmEnvironment Environment { get; set; }
-	}
+        internal int BlockEnd { get; set; }
 
+        public VmEnvironment Environment { get; internal set; }
+    }
 }