AST refactoring

2025-08-29 09:44:17 +02:00
parent 5593761551
commit fa9328a183
9 changed files with 524 additions and 514 deletions
@@ -0,0 +1,305 @@
+unit Myc.Ast.Nodes;
+
+interface
+
+uses
+    System.SysUtils,
+    System.Generics.Collections,
+    Myc.Data.POD;
+
+type
+    // Operators and helpers
+    TBinaryOperator = (boAdd, boSubtract, boMultiply, boDivide, boEqual, boNotEqual, boLess, boGreater, boLessOrEqual, boGreaterOrEqual);
+    TUnaryOperator = (uoNegate, uoNot);
+
+    TBinaryOperatorHelper = record helper for TBinaryOperator
+        function ToString: string;
+    end;
+
+    TUnaryOperatorHelper = record helper for TUnaryOperator
+        function ToString: string;
+    end;
+
+    TAstValueKind = (avkUndefined, avkScalar, avkClosure);
+
+    // --- Forward Declarations to break cycles ---
+    IExecutionScope = interface;
+    IAstVisitor = interface;
+    IAstNode = interface;
+    IExpressionNode = interface;
+    IIdentifierNode = interface;
+    IConstantNode = interface;
+    IBinaryExpressionNode = interface;
+    IUnaryExpressionNode = interface;
+    IIfExpressionNode = interface;
+    ILambdaExpressionNode = interface;
+    IFunctionCallNode = interface;
+    IBlockExpressionNode = interface;
+    IVariableDeclarationNode = interface;
+    IAssignmentNode = interface;
+    IEvaluatorClosure = interface;
+
+    // --- Concrete Type Definitions ---
+
+    IEvaluatorClosure = interface(IInterface)
+        {$region 'private'}
+        function GetBody: IExpressionNode;
+        function GetParameters: TArray<IIdentifierNode>;
+        function GetClosureScope: IExecutionScope;
+        {$endregion}
+        property Body: IExpressionNode read GetBody;
+        property Parameters: TArray<IIdentifierNode> read GetParameters;
+        property ClosureScope: IExecutionScope read GetClosureScope;
+    end;
+
+    TAstValue = record
+    private
+        FKind: TAstValueKind;
+        FScalar: TScalar;
+        FClosure: IEvaluatorClosure;
+        function GetKind: TAstValueKind; inline;
+        function GetIsScalar: Boolean; inline;
+        function GetIsClosure: Boolean; inline;
+        function GetIsUndefined: Boolean; inline;
+    public
+        class operator Initialize(out Dest: TAstValue);
+        class function Undefined: TAstValue; static;
+        class function FromScalar(const AValue: TScalar): TAstValue; static;
+        class function FromClosure(const AValue: IEvaluatorClosure): TAstValue; static;
+        function AsScalar: TScalar;
+        function AsClosure: IEvaluatorClosure;
+        function ToString: String;
+        property Kind: TAstValueKind read GetKind;
+        property IsScalar: Boolean read GetIsScalar;
+        property IsClosure: Boolean read GetIsClosure;
+        property IsUndefined: Boolean read GetIsUndefined;
+    end;
+
+    IExecutionScope = interface(IInterface)
+        {$region 'private'}
+        function GetParent: IExecutionScope;
+        {$endregion}
+        procedure Clear;
+        function FindValue(const Name: string; out Value: TAstValue): Boolean;
+        procedure SetValue(const Name: string; const Value: TAstValue);
+        procedure AssignValue(const Name: string; const Value: TAstValue);
+        function Dump: string;
+        property Parent: IExecutionScope read GetParent;
+    end;
+
+    IAstVisitor = interface
+        ['{A58B0A8E-F438-4217-A964-6E35624A9A4A}']
+        function VisitConstant(const Node: IConstantNode): TAstValue;
+        function VisitIdentifier(const Node: IIdentifierNode): TAstValue;
+        function VisitBinaryExpression(const Node: IBinaryExpressionNode): TAstValue;
+        function VisitUnaryExpression(const Node: IUnaryExpressionNode): TAstValue;
+        function VisitIfExpression(const Node: IIfExpressionNode): TAstValue;
+        function VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue;
+        function VisitFunctionCall(const Node: IFunctionCallNode): TAstValue;
+        function VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
+        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
+        function VisitAssignment(const Node: IAssignmentNode): TAstValue;
+    end;
+
+    IAstNode = interface(IInterface)
+        function Accept(const Visitor: IAstVisitor): TAstValue;
+    end;
+
+    IExpressionNode = interface(IAstNode)
+    end;
+
+    IConstantNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetValue: TScalar;
+        {$endregion}
+        property Value: TScalar read GetValue;
+    end;
+
+    IIdentifierNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetName: string;
+        {$endregion}
+        property Name: string read GetName;
+    end;
+
+    IBinaryExpressionNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetLeft: IExpressionNode;
+        function GetOperator: TBinaryOperator;
+        function GetRight: IExpressionNode;
+        {$endregion}
+        property Left: IExpressionNode read GetLeft;
+        property Operator: TBinaryOperator read GetOperator;
+        property Right: IExpressionNode read GetRight;
+    end;
+
+    IUnaryExpressionNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetOperator: TUnaryOperator;
+        function GetRight: IExpressionNode;
+        {$endregion}
+        property Operator: TUnaryOperator read GetOperator;
+        property Right: IExpressionNode read GetRight;
+    end;
+
+    IIfExpressionNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetCondition: IExpressionNode;
+        function GetThenBranch: IExpressionNode;
+        function GetElseBranch: IExpressionNode;
+        {$endregion}
+        property Condition: IExpressionNode read GetCondition;
+        property ThenBranch: IExpressionNode read GetThenBranch;
+        property ElseBranch: IExpressionNode read GetElseBranch;
+    end;
+
+    ILambdaExpressionNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetParameters: TArray<IIdentifierNode>;
+        function GetBody: IExpressionNode;
+        {$endregion}
+        property Parameters: TArray<IIdentifierNode> read GetParameters;
+        property Body: IExpressionNode read GetBody;
+    end;
+
+    IFunctionCallNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetCallee: IExpressionNode;
+        function GetArguments: TList<IExpressionNode>;
+        {$endregion}
+        property Callee: IExpressionNode read GetCallee;
+        property Arguments: TList<IExpressionNode> read GetArguments;
+    end;
+
+    IBlockExpressionNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetExpressions: TList<IExpressionNode>;
+        {$endregion}
+        property Expressions: TList<IExpressionNode> read GetExpressions;
+    end;
+
+    IVariableDeclarationNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetIdentifier: IIdentifierNode;
+        function GetInitializer: IExpressionNode;
+        {$endregion}
+        property Identifier: IIdentifierNode read GetIdentifier;
+        property Initializer: IExpressionNode read GetInitializer;
+    end;
+
+    IAssignmentNode = interface(IExpressionNode)
+        {$region 'private'}
+        function GetIdentifier: IIdentifierNode;
+        function GetValue: IExpressionNode;
+        {$endregion}
+        property Identifier: IIdentifierNode read GetIdentifier;
+        property Value: IExpressionNode read GetValue;
+    end;
+
+implementation
+
+{ TAstValue }
+
+class operator TAstValue.Initialize(out Dest: TAstValue);
+begin
+    Dest.FKind := avkUndefined;
+    Dest.FClosure := nil;
+end;
+
+function TAstValue.AsClosure: IEvaluatorClosure;
+begin
+    if (FKind <> avkClosure) then
+        raise EInvalidCast.Create('Cannot read value as a Closure.');
+    Result := FClosure;
+end;
+
+function TAstValue.AsScalar: TScalar;
+begin
+    if (FKind <> avkScalar) then
+        raise EInvalidCast.Create('Cannot read value as a Scalar.');
+    Result := FScalar;
+end;
+
+class function TAstValue.FromClosure(const AValue: IEvaluatorClosure): TAstValue;
+begin
+    Result.FKind := avkClosure;
+    Result.FClosure := AValue;
+    Result.FScalar := Default(TScalar);
+end;
+
+class function TAstValue.FromScalar(const AValue: TScalar): TAstValue;
+begin
+    Result.FKind := avkScalar;
+    Result.FScalar := AValue;
+    Result.FClosure := nil;
+end;
+
+function TAstValue.GetIsClosure: Boolean;
+begin
+    Result := FKind = avkClosure;
+end;
+
+function TAstValue.GetIsScalar: Boolean;
+begin
+    Result := FKind = avkScalar;
+end;
+
+function TAstValue.GetIsUndefined: Boolean;
+begin
+    Result := FKind = avkUndefined;
+end;
+
+function TAstValue.GetKind: TAstValueKind;
+begin
+    Result := FKind;
+end;
+
+function TAstValue.ToString: String;
+begin
+    case FKind of
+        avkScalar: Result := FScalar.ToString;
+        avkClosure: Result := '<closure>';
+        avkUndefined: Result := '<void>';
+    else
+        Result := '[Unknown AstValue]';
+    end;
+end;
+
+class function TAstValue.Undefined: TAstValue;
+begin
+    Result := Default(TAstValue);
+end;
+
+{ TBinaryOperatorHelper }
+
+function TBinaryOperatorHelper.ToString: string;
+begin
+    case Self of
+        boAdd: Result := '+';
+        boSubtract: Result := '-';
+        boMultiply: Result := '*';
+        boDivide: Result := '/';
+        boEqual: Result := '==';
+        boNotEqual: Result := '!=';
+        boLess: Result := '<';
+        boGreater: Result := '>';
+        boLessOrEqual: Result := '<=';
+        boGreaterOrEqual: Result := '>=';
+    else
+        Result := '?';
+    end;
+end;
+
+{ TUnaryOperatorHelper }
+
+function TUnaryOperatorHelper.ToString: string;
+begin
+    case Self of
+        uoNegate: Result := '-';
+        uoNot: Result := 'not';
+    else
+        Result := '?';
+    end;
+end;
+
+end.