From 9010bb18904b1065dacb5dcbbf4c3a46199d6bd6 Mon Sep 17 00:00:00 2001
From: Michael Schimmel <schimmel@mycelium.de>
Date: Tue, 30 Sep 2025 11:34:35 +0200
Subject: [PATCH] Preparing for atomic data values

---
 Src/Data/Myc.Data.Value.pas | 205 ++++++++----------------------------
 1 file changed, 43 insertions(+), 162 deletions(-)

diff --git a/Src/Data/Myc.Data.Value.pas b/Src/Data/Myc.Data.Value.pas
index 453930a..e93613c 100644
--- a/Src/Data/Myc.Data.Value.pas
+++ b/Src/Data/Myc.Data.Value.pas
@@ -30,22 +30,11 @@ type
                 destructor Destroy; override;
             end;
 
-            ILazy = interface
-                function GetKind: TDataValueKind;
-                function GetValue: TDataValue;
-                property Kind: TDataValueKind read GetKind;
-                property Value: TDataValue read GetValue;
-            end;
-
-            TInternalKind = (vkLazy = Ord(High(TDataValueKind)) + 1);
-            TInternalKindOrdinal = 0..Ord(High(TInternalKind));
-
         var
-            FKind: TInternalKindOrdinal;
+            FKind: TDataValueKind;
             FScalar: TScalar;
             FInterface: IInterface;
 
-        function AsLazy: ILazy; inline;
         function GetKind: TDataValueKind; inline;
         function GetIsVoid: Boolean; inline;
 
@@ -61,6 +50,9 @@ type
         class operator Implicit(const AValue: TDataValue.TFunc): TDataValue; overload; inline;
         class operator Implicit(const AValue: TObject): TDataValue; overload; inline;
 
+        class function CompareAndSet(var Target: TDataValue; const Expected, NewValue: TDataValue): Boolean; static;
+        class function Reset(var Target: TDataValue; const NewValue: TDataValue): TDataValue; static;
+
         class function FromIntf<T: IInterface>(const AValue: T): TDataValue; static;
         function AsIntf<T: IInterface>: T; inline;
 
@@ -70,8 +62,6 @@ type
         class function FromPtr(const AValue: Pointer): TDataValue; static; inline;
         function AsPtr: Pointer; inline;
 
-        class function Defer(const Value: TDataValue; const Calc: TFunc): TDataValue; overload; static;
-
         class function Map(const SourceSeries: ISeries; const MapperFunc: TFunc): ISeries; static;
 
         class function FromRecordSeries(const AValue: IRecordSeries): TDataValue; static; inline;
@@ -102,27 +92,6 @@ uses
     TypInfo;
 
 type
-    TManagedLazy = class(TInterfacedObject, TDataValue.ILazy)
-    private
-        FKind: TDataValueKind;
-        FVal: IInterface;
-        FCalc: TDataValue.TFunc;
-        function GetValue: TDataValue;
-        function GetKind: TDataValueKind;
-    public
-        constructor Create(AKind: TDataValueKind; const AVal: IInterface; const ACalc: TDataValue.TFunc);
-    end;
-
-    TScalarLazy = class(TInterfacedObject, TDataValue.ILazy)
-    private
-        FVal: TScalar;
-        FCalc: TDataValue.TFunc;
-        function GetKind: TDataValueKind;
-        function GetValue: TDataValue;
-    public
-        constructor Create(const AVal: TScalar; const ACalc: TDataValue.TFunc);
-    end;
-
     TMapSeries = class(TInterfacedObject, ISeries)
     private
         FSourceSeries: ISeries;
@@ -135,46 +104,6 @@ type
         constructor Create(const ASourceSeries: ISeries; const AMapperFunc: TDataValue.TFunc);
     end;
 
-constructor TManagedLazy.Create(AKind: TDataValueKind; const AVal: IInterface; const ACalc: TDataValue.TFunc);
-begin
-    inherited Create;
-    FKind := AKind;
-    Assert(FKind <> vkVoid);
-    FVal := AVal;
-    FCalc := ACalc;
-end;
-
-function TManagedLazy.GetKind: TDataValueKind;
-begin
-    Result := FKind;
-end;
-
-function TManagedLazy.GetValue: TDataValue;
-var
-    dv: TDataValue;
-begin
-    dv.FKind := Ord(FKind);
-    dv.FInterface := FVal;
-    Result := FCalc([dv]);
-end;
-
-constructor TScalarLazy.Create(const AVal: TScalar; const ACalc: TDataValue.TFunc);
-begin
-    inherited Create;
-    FVal := AVal;
-    FCalc := ACalc;
-end;
-
-function TScalarLazy.GetKind: TDataValueKind;
-begin
-    Result := vkScalar;
-end;
-
-function TScalarLazy.GetValue: TDataValue;
-begin
-    Result := FCalc([FVal]);
-end;
-
 { TDataValue.TVal<T> }
 
 constructor TDataValue.TVal<T>.Create(const AValue: T);
@@ -186,43 +115,31 @@ begin
 {$endif}
 end;
 
-function TDataValue.AsLazy: ILazy;
-begin
-    Assert(FKind = Ord(vkLazy));
-    Result := ILazy(FInterface);
-end;
-
 { TDataValue }
 
 class operator TDataValue.Initialize(out Dest: TDataValue);
 begin
-    Dest.FKind := Ord(vkVoid);
+    Dest.FKind := vkVoid;
     Dest.FInterface := nil;
 end;
 
 function TDataValue.AsSeries: ISeries;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsSeries);
-    if (FKind <> Ord(vkSeries)) then
+    if (FKind <> vkSeries) then
         raise EInvalidCast.Create('Cannot read value as MemberSeries.');
     Result := ISeries(FInterface);
 end;
 
 function TDataValue.AsMethod: TFunc;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsMethod);
-    if (FKind <> Ord(vkMethod)) then
+    if (FKind <> vkMethod) then
         raise EInvalidCast.Create('Cannot read value as a method.');
     Result := TFunc(FInterface);
 end;
 
 function TDataValue.AsGeneric<T>: T;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsGeneric<T>);
-    if FKind <> Ord(vkGeneric) then
+    if FKind <> vkGeneric then
         raise EInvalidCast.Create('Cannot read value as generic of ' + String(PTypeInfo(TypeInfo(T)).Name) + '.');
 {$ifdef DEBUG}
     if TVal<T>(FInterface).TypeHandle <> TypeInfo(T) then
@@ -233,155 +150,115 @@ end;
 
 function TDataValue.AsIntf<T>: T;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsGeneric<T>);
-    if FKind <> Ord(vkInterface) then
+    if FKind <> vkInterface then
         raise EInvalidCast.Create('Cannot read value as interface.');
     Result := T(FInterface);
 end;
 
 function TDataValue.AsObject: TObject;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsObject);
-    if (FKind <> Ord(vkManagedObject)) then
+    if (FKind <> vkManagedObject) then
         raise EInvalidCast.Create('Cannot read value as object.');
     Result := (FInterface as TObjVal).Value;
 end;
 
 function TDataValue.AsPtr: Pointer;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsPtr);
-    if (FKind <> Ord(vkPointer)) then
+    if (FKind <> vkPointer) then
         raise EInvalidCast.Create('Cannot read value as pointer.');
     Result := Pointer(FScalar.Value.AsInt64);
 end;
 
 function TDataValue.AsRecord: TScalarRecord;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsRecord);
-    if (FKind <> Ord(vkRecord)) then
+    if (FKind <> vkRecord) then
         raise EInvalidCast.Create('Cannot read value as Record.');
     Result := (FInterface as TVal<TScalarRecord>).Value;
 end;
 
 function TDataValue.AsRecordSeries: IRecordSeries;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsRecordSeries);
-    if (FKind <> Ord(vkRecordSeries)) then
+    if (FKind <> vkRecordSeries) then
         raise EInvalidCast.Create('Cannot read value as RecordSeries.');
     Result := IRecordSeries(FInterface);
 end;
 
 function TDataValue.AsScalar: TScalar;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsScalar);
-    if (FKind <> Ord(vkScalar)) then
+    if (FKind <> vkScalar) then
         raise EInvalidCast.Create('Cannot read value as a Scalar.');
     Result := FScalar;
 end;
 
 function TDataValue.AsText: String;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Value.AsText);
-    if (FKind <> Ord(vkText)) then
+    if (FKind <> vkText) then
         raise EInvalidCast.Create('Cannot read value as Text.');
     Result := (FInterface as TVal<String>).Value;
 end;
 
-class function TDataValue.Defer(const Value: TDataValue; const Calc: TFunc): TDataValue;
+class function TDataValue.CompareAndSet(var Target: TDataValue; const Expected, NewValue: TDataValue): Boolean;
 begin
-    Result.FKind := Ord(vkLazy);
-    case Value.FKind of
-        Ord(vkScalar): Result.FInterface := TScalarLazy.Create(Value.AsScalar, Calc);
-        Ord(vkLazy):
-        begin
-            // Create a new lazy object that wraps the existing one, passing the original
-            // kind and the inner lazy interface.
-            var cCalc: TFunc := Calc;
-            Result.FInterface :=
-                TManagedLazy.Create(
-                    Value.AsLazy.Kind,
-                    Value.FInterface,
-                    function(const ArgNodes: TArray<TDataValue>): TDataValue
-                    begin
-                        // Chain lazy computations. The new calculation function will first evaluate
-                        // the inner lazy value and then pass the result to the new calculation.
-                        // The reconstructed TDataValue in ArgNodes[0] contains the inner ILazy interface.
-                        Assert(Length(ArgNodes) = 1, 'Expected 1 argument in lazy computation chain');
-                        Result := cCalc([ILazy(ArgNodes[0].FInterface).Value]);
-                    end
-                );
-        end;
-    else
-        Result.FInterface := TManagedLazy.Create(Value.Kind, Value.FInterface, Calc);
-    end;
+    //    Result := ;
 end;
 
 class function TDataValue.FromIntf<T>(const AValue: T): TDataValue;
 begin
-    Result.FKind := Ord(vkInterface);
+    Result.FKind := vkInterface;
     Result.FInterface := IInterface(AValue);
 end;
 
 class function TDataValue.FromGeneric<T>(const [ref] AValue: T): TDataValue;
 begin
-    Result.FKind := Ord(vkGeneric);
+    Result.FKind := vkGeneric;
     Result.FInterface := TVal<T>.Create(AValue);
 end;
 
 class function TDataValue.FromPtr(const AValue: Pointer): TDataValue;
 begin
     Assert(sizeof(Pointer) <= sizeof(Int64));
-    Result.FKind := Ord(vkPointer);
+    Result.FKind := vkPointer;
     Result.FScalar.FromInt64(Int64(AValue));
 end;
 
 class function TDataValue.FromSeries(const AValue: ISeries): TDataValue;
 begin
-    Result.FKind := Ord(vkSeries);
+    Result.FKind := vkSeries;
     Result.FInterface := AValue;
 end;
 
 class function TDataValue.FromRecord(const [ref] AValue: TScalarRecord): TDataValue;
 begin
-    Result.FKind := Ord(vkRecord);
+    Result.FKind := vkRecord;
     Result.FInterface := TVal<TScalarRecord>.Create(AValue);
 end;
 
 class function TDataValue.FromRecordSeries(const AValue: IRecordSeries): TDataValue;
 begin
-    Result.FKind := Ord(vkRecordSeries);
+    Result.FKind := vkRecordSeries;
     Result.FInterface := AValue;
 end;
 
 class operator TDataValue.Implicit(const AValue: TScalar): TDataValue;
 begin
-    Result.FKind := Ord(vkScalar);
+    Result.FKind := vkScalar;
     Result.FScalar := AValue;
     Result.FInterface := nil;
 end;
 
 class operator TDataValue.Implicit(const AValue: String): TDataValue;
 begin
-    Result.FKind := Ord(vkText);
+    Result.FKind := vkText;
     Result.FInterface := TVal<String>.Create(AValue);
 end;
 
 function TDataValue.GetIsVoid: Boolean;
 begin
-    Result := FKind = Ord(vkVoid);
+    Result := FKind = vkVoid;
 end;
 
 function TDataValue.GetKind: TDataValueKind;
 begin
-    if FKind = Ord(vkLazy) then
-        exit(AsLazy.Kind);
     Result := TDataValueKind(FKind);
 end;
 
@@ -390,6 +267,11 @@ begin
     Result := TMapSeries.Create(SourceSeries, MapperFunc);
 end;
 
+class function TDataValue.Reset(var Target: TDataValue; const NewValue: TDataValue): TDataValue;
+begin
+    //    Result := ;
+end;
+
 function TDataValue.ToString: String;
 var
     sb: TStringBuilder;
@@ -397,15 +279,15 @@ var
     first: Boolean;
 begin
     case FKind of
-        Ord(vkScalar): Result := FScalar.ToString;
-        Ord(vkText): Result := '"' + AsText + '"';
-        Ord(vkSeries):
+        vkScalar: Result := FScalar.ToString;
+        vkText: Result := '"' + AsText + '"';
+        vkSeries:
         begin
             var series := AsSeries;
             // Add type and count for series
             Result := Format('<series[%d]>', [series.Count]);
         end;
-        Ord(vkRecordSeries):
+        vkRecordSeries:
         begin
             var series := AsRecordSeries;
             sb := TStringBuilder.Create;
@@ -426,7 +308,7 @@ begin
                 sb.Free;
             end;
         end;
-        Ord(vkRecord):
+        vkRecord:
         begin
             var rec := AsRecord;
             sb := TStringBuilder.Create;
@@ -447,13 +329,12 @@ begin
                 sb.Free;
             end;
         end;
-        Ord(vkVoid): Result := '<void>';
-        Ord(vkMethod): Result := '<method>';
-        Ord(vkGeneric):
+        vkVoid: Result := '<void>';
+        vkMethod: Result := '<method>';
+        vkGeneric:
             // Getting meaningful type information for vkGeneric is not easily possible
             // without storing additional RTTI, as the specific type of T in TVal<T> is lost.
             Result := '<generic>';
-        Ord(vkLazy): Result := Format('<lazy[%s]>', [AsLazy.Kind.ToString]);
     else
         Result := '[Unknown DataValue]';
     end;
@@ -466,13 +347,13 @@ end;
 
 class operator TDataValue.Implicit(const AValue: TDataValue.TFunc): TDataValue;
 begin
-    Result.FKind := Ord(vkMethod);
+    Result.FKind := vkMethod;
     TFunc(Result.FInterface) := AValue;
 end;
 
 class operator TDataValue.Implicit(const AValue: TObject): TDataValue;
 begin
-    Result.FKind := Ord(vkManagedObject);
+    Result.FKind := vkManagedObject;
     Result.FInterface := TObjVal.Create(AValue);
 end;
 
@@ -483,14 +364,14 @@ end;
 
 class operator TDataValue.Implicit(const AValue: Int64): TDataValue;
 begin
-    Result.FKind := Ord(vkScalar);
+    Result.FKind := vkScalar;
     Result.FScalar := TScalar.FromInt64(AValue);
     Result.FInterface := nil;
 end;
 
 class operator TDataValue.Implicit(const AValue: Double): TDataValue;
 begin
-    Result.FKind := Ord(vkScalar);
+    Result.FKind := vkScalar;
     Result.FScalar := TScalar.FromDouble(AValue);
     Result.FInterface := nil;
 end;