Michael Schimmel
124 lines
3.4 KiB
ObjectPascal
124 lines
3.4 KiB
ObjectPascal
unit Myc.Ast.Scope;
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interface
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uses
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System.SysUtils,
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System.Generics.Collections,
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System.Classes,
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Myc.Ast.Nodes;
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type
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TExecutionScope = class(TInterfacedObject, IExecutionScope)
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private
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FParent: IExecutionScope;
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FVariables: TDictionary<string, TAstValue>;
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procedure DumpScope(const ABuilder: TStringBuilder; AIndent: Integer);
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protected
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// IExecutionScope
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function GetParent: IExecutionScope;
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procedure Clear;
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function FindValue(const Name: string; out Value: TAstValue): Boolean;
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procedure SetValue(const Name: string; const Value: TAstValue);
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procedure AssignValue(const Name: string; const Value: TAstValue);
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function Dump: string;
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public
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constructor Create(AParent: IExecutionScope = nil);
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destructor Destroy; override;
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end;
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implementation
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{ TExecutionScope }
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constructor TExecutionScope.Create(AParent: IExecutionScope);
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begin
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inherited Create;
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FParent := AParent;
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FVariables := TDictionary<string, TAstValue>.Create;
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end;
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destructor TExecutionScope.Destroy;
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begin
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FVariables.Free;
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inherited Destroy;
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end;
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function TExecutionScope.GetParent: IExecutionScope;
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begin
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Result := FParent;
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end;
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procedure TExecutionScope.AssignValue(const Name: string; const Value: TAstValue);
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begin
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if FVariables.ContainsKey(Name) then
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FVariables.AddOrSetValue(Name, Value)
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else if Assigned(FParent) then
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FParent.AssignValue(Name, Value)
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else
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raise Exception.CreateFmt('Cannot assign to undeclared variable "%s".', [Name]);
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end;
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procedure TExecutionScope.Clear;
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begin
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FVariables.Clear;
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if Assigned(FParent) then
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FParent.Clear;
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end;
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procedure TExecutionScope.DumpScope(const ABuilder: TStringBuilder; AIndent: Integer);
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var
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pair: TPair<string, TAstValue>;
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indentStr: string;
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begin
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indentStr := ''.PadLeft(AIndent);
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if (FVariables.Count > 0) then
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begin
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for pair in FVariables do
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ABuilder.AppendLine(indentStr + Format(' %s: %s', [pair.Key, pair.Value.ToString]));
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end
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else
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begin
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ABuilder.AppendLine(indentStr + ' (empty)');
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end;
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if Assigned(FParent) then
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begin
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ABuilder.AppendLine(indentStr + '[Parent Scope]');
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// As FParent is now an interface, we must cast it back to the class to call the private DumpScope.
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// This indicates that DumpScope should perhaps be part of the interface or handled differently.
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// For now, we use a cast to keep the functionality.
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(FParent as TExecutionScope).DumpScope(ABuilder, AIndent + 2);
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end;
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end;
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function TExecutionScope.Dump: string;
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var
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builder: TStringBuilder;
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begin
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builder := TStringBuilder.Create;
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try
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builder.AppendLine('[Current Scope]');
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DumpScope(builder, 0);
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Result := builder.ToString.TrimRight;
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finally
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builder.Free;
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end;
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end;
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function TExecutionScope.FindValue(const Name: string; out Value: TAstValue): Boolean;
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begin
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Result := FVariables.TryGetValue(Name, Value);
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if not Result and Assigned(FParent) then
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begin
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Result := FParent.FindValue(Name, Value);
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end;
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end;
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procedure TExecutionScope.SetValue(const Name: string; const Value: TAstValue);
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begin
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FVariables.AddOrSetValue(Name, Value);
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end;
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end.
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