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AST refactoring

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This commit is contained in:
Michael Schimmel
2025-08-29 00:27:17 +02:00
parent 5451f4fed9
commit 5593761551
6 changed files with 294 additions and 36 deletions
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Src/AST/Myc.Ast.pas
+87 -23
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@@ -42,6 +42,7 @@ type
IFunctionCallNode = interface;
IBlockExpressionNode = interface;
IVariableDeclarationNode = interface;
IAssignmentNode = interface; // Represents an assignment to an existing variable.
IEvaluatorClosure = interface;
TExecutionScope = class;
@@ -51,11 +52,11 @@ type
IEvaluatorClosure = interface(IInterface)
{$region 'private'}
function GetBody: IExpressionNode;
function GetParameters: TList<IIdentifierNode>;
function GetParameters: TArray<IIdentifierNode>;
function GetClosureScope: TExecutionScope;
{$endregion}
property Body: IExpressionNode read GetBody;
property Parameters: TList<IIdentifierNode> read GetParameters;
property Parameters: TArray<IIdentifierNode> read GetParameters;
property ClosureScope: TExecutionScope read GetClosureScope;
end;
@@ -103,6 +104,7 @@ type
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;
// --- AST Node Interfaces (now using TAstValue) ---
@@ -163,10 +165,10 @@ type
ILambdaExpressionNode = interface(IExpressionNode)
{$region 'private'}
function GetParameters: TList<IIdentifierNode>;
function GetParameters: TArray<IIdentifierNode>;
function GetBody: IExpressionNode;
{$endregion}
property Parameters: TList<IIdentifierNode> read GetParameters;
property Parameters: TArray<IIdentifierNode> read GetParameters;
property Body: IExpressionNode read GetBody;
end;
@@ -197,6 +199,16 @@ type
property Initializer: IExpressionNode read GetInitializer;
end;
// An assignment expression that returns the assigned value.
IAssignmentNode = interface(IExpressionNode)
{$region 'private'}
function GetIdentifier: IIdentifierNode;
function GetValue: IExpressionNode;
{$endregion}
property Identifier: IIdentifierNode read GetIdentifier;
property Value: IExpressionNode read GetValue;
end;
// Record acting as a namespace for the factory functions.
TAst = record
class function Constant(AValue: TScalar): IConstantNode; static;
@@ -211,10 +223,11 @@ type
const ACondition: IExpressionNode;
const AThenBranch, AElseBranch: IExpressionNode
): IIfExpressionNode; static;
class function LambdaExpr(const AParameters: array of IIdentifierNode; const ABody: IExpressionNode): ILambdaExpressionNode; static;
class function LambdaExpr(const AParameters: TArray<IIdentifierNode>; const ABody: IExpressionNode): ILambdaExpressionNode; static;
class function FunctionCall(const ACallee: IExpressionNode; const AArguments: array of IExpressionNode): IFunctionCallNode; static;
class function Block(const AExpressions: array of IExpressionNode): IBlockExpressionNode; static;
class function VarDecl(const AIdentifier: IIdentifierNode; AInitializer: IExpressionNode): IVariableDeclarationNode; static;
class function Assign(const AIdentifier: IIdentifierNode; const AValue: IExpressionNode): IAssignmentNode; static;
end;
// Manages the scope of execution, holding variables and their values.
@@ -226,8 +239,12 @@ type
public
constructor Create(AParent: TExecutionScope = nil);
destructor Destroy; override;
procedure Clear;
function FindValue(const Name: string; out Value: TAstValue): Boolean;
// Sets or updates a value in the current scope. Used for declarations.
procedure SetValue(const Name: string; const Value: TAstValue);
// Finds an existing variable in the scope chain and updates its value. Used for assignments.
procedure AssignValue(const Name: string; const Value: TAstValue);
function Dump: string;
end;
@@ -304,13 +321,12 @@ type
{ TLambdaExpressionNode }
TLambdaExpressionNode = class(TAstNode, ILambdaExpressionNode)
private
FParameters: TList<IIdentifierNode>;
FParameters: TArray<IIdentifierNode>;
FBody: IExpressionNode;
function GetParameters: TList<IIdentifierNode>;
function GetParameters: TArray<IIdentifierNode>;
function GetBody: IExpressionNode;
public
constructor Create(const AParameters: array of IIdentifierNode; const ABody: IExpressionNode);
destructor Destroy; override;
constructor Create(const AParameters: TArray<IIdentifierNode>; const ABody: IExpressionNode);
function Accept(const Visitor: IAstVisitor): TAstValue; override;
end;
@@ -350,6 +366,18 @@ type
function Accept(const Visitor: IAstVisitor): TAstValue; override;
end;
{ TAssignmentNode }
TAssignmentNode = class(TAstNode, IAssignmentNode)
private
FIdentifier: IIdentifierNode;
FValue: IExpressionNode;
function GetIdentifier: IIdentifierNode;
function GetValue: IExpressionNode;
public
constructor Create(const AIdentifier: IIdentifierNode; const AValue: IExpressionNode);
function Accept(const Visitor: IAstVisitor): TAstValue; override;
end;
{ TAstValue }
class operator TAstValue.Initialize(out Dest: TAstValue);
@@ -577,21 +605,11 @@ end;
{ TLambdaExpressionNode }
constructor TLambdaExpressionNode.Create(const AParameters: array of IIdentifierNode; const ABody: IExpressionNode);
var
param: IIdentifierNode;
constructor TLambdaExpressionNode.Create(const AParameters: TArray<IIdentifierNode>; const ABody: IExpressionNode);
begin
inherited Create;
FBody := ABody;
FParameters := TList<IIdentifierNode>.Create;
for param in AParameters do
FParameters.Add(param);
end;
destructor TLambdaExpressionNode.Destroy;
begin
FParameters.Free;
inherited;
FParameters := AParameters;
end;
function TLambdaExpressionNode.Accept(const Visitor: IAstVisitor): TAstValue;
@@ -604,7 +622,7 @@ begin
Result := FBody;
end;
function TLambdaExpressionNode.GetParameters: TList<IIdentifierNode>;
function TLambdaExpressionNode.GetParameters: TArray<IIdentifierNode>;
begin
Result := FParameters;
end;
@@ -695,8 +713,37 @@ begin
Result := FInitializer;
end;
{ TAssignmentNode }
constructor TAssignmentNode.Create(const AIdentifier: IIdentifierNode; const AValue: IExpressionNode);
begin
inherited Create;
FIdentifier := AIdentifier;
FValue := AValue;
end;
function TAssignmentNode.Accept(const Visitor: IAstVisitor): TAstValue;
begin
Result := Visitor.VisitAssignment(Self);
end;
function TAssignmentNode.GetIdentifier: IIdentifierNode;
begin
Result := FIdentifier;
end;
function TAssignmentNode.GetValue: IExpressionNode;
begin
Result := FValue;
end;
{ TAst }
class function TAst.Assign(const AIdentifier: IIdentifierNode; const AValue: IExpressionNode): IAssignmentNode;
begin
Result := TAssignmentNode.Create(AIdentifier, AValue);
end;
class function TAst.Block(const AExpressions: array of IExpressionNode): IBlockExpressionNode;
begin
Result := TBlockExpressionNode.Create(AExpressions);
@@ -727,7 +774,7 @@ begin
Result := TIfExpressionNode.Create(ACondition, AThenBranch, AElseBranch);
end;
class function TAst.LambdaExpr(const AParameters: array of IIdentifierNode; const ABody: IExpressionNode): ILambdaExpressionNode;
class function TAst.LambdaExpr(const AParameters: TArray<IIdentifierNode>; const ABody: IExpressionNode): ILambdaExpressionNode;
begin
Result := TLambdaExpressionNode.Create(AParameters, ABody);
end;
@@ -757,6 +804,23 @@ begin
inherited Destroy;
end;
procedure TExecutionScope.AssignValue(const Name: string; const Value: TAstValue);
begin
if FVariables.ContainsKey(Name) then
FVariables.AddOrSetValue(Name, Value)
else if Assigned(FParent) then
FParent.AssignValue(Name, Value)
else
raise Exception.CreateFmt('Cannot assign to undeclared variable "%s".', [Name]);
end;
procedure TExecutionScope.Clear;
begin
FVariables.Clear;
if Assigned(FParent) then
FParent.Clear;
end;
procedure TExecutionScope.DumpScope(const ABuilder: TStringBuilder; AIndent: Integer);
var
pair: TPair<string, TAstValue>;