Differences

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--- 0.8.3:scripting [2021/10/13 13:20] – [Scripting] admin
+++ 0.8.3:scripting [2021/10/13 13:42] (current) – [Global Functions] admin
@@ Line 491: / Line 491: @@
 </file>
+===== Global Constants =====
+<file pascal>
+const
+	DEFAULT_STR : String = 'Test' + '-Output-' + 'Test:';
+</file>
 ===== Local Variables =====
 Local variables are declared like Delphi syntax by the "var" identifier.
@@ Line 552: / Line 558: @@
 			FFieldDbl : Double;
 			FFieldObj : TTest;
+	end;
+</file>
+=== Properties ===
+Properties are a very useful tool to access fields directly or by a getter or setter method.
+In the following example we extend our TTest class by a GetFieldBool() and SetFieldBool() protected method.
+In the public property "FieldBool" we can access the protected field "FFieldBool" by those methods
+indirectly. We than have the option to influence behaviour.
+The second property "FieldStr" is set to read-only on our protected field "FFieldStr", which forbids writing to. Of course this can also be done by getter or setter methods.
+The third property "FieldInt" allows reading and writing operations directly on the protected field "FFieldInt"
+Note: You can mix getter/setter methods and direct field access on read/write.
+<file pascal>
+	TTest = class
+		protected
+			FFieldBool : Boolean;
+			FFieldStr : String;
+			FFieldInt : Int32;
+			function GetFieldBool() : Boolean;
+			procedure SetFieldBool(AValue : Boolean);
+		public
+			FFieldDbl : Double;
+			FFieldObj : TTest;
+			property FieldBool : Boolean read GetFieldBool write SetFieldBool;
+			property FieldStr : String read FFieldStr;
+			property FieldInt : Int32 read FFieldInt write FFieldInt;
 	end;
 </file>
@@ Line 557: / Line 596: @@
 === Methods ===
-=== Properties ===
+Functions and procedures declared in a class, interface or record are called methods.
+Those can be defined in all available viewspaces (private, protected, public, published) like fields.
+But besides a simple object method declaration, Delphi offers constructors, destructors
+and class functions / class procedures. They are declared by a different reserved word, because their
+behaviour is a bit different than the simple methods.
+Constructors are getting automatically called on instance creation and destructors when an instance is about to be destroyed.
+Class functions / procedures OR static methods are like simple functions and procedures, but they are called in different context.
+Regular functions/procedures are called by an instance (object) of the class, while static methods are called by the class itself.
+So they have no instance context and therefore no access to fields or object methods.
+This is getting important, when using "Self" in those methods. For static methods it is the class type itself, but for object methods it's the object.
+<file pascal>
+	TTest = class
+		protected
+			[...]
+			function Calculate(AFactor : Double) : Double; virtual;
+		public
+			[...]
+			constructor Create(); virtual;
+			destructor Destroy(); override;
+			class function GetDefaultStr() : String;
+			procedure Output(AIdx : Integer);
+	end;
+</file>
+After our method head declaration is done, we need to implement the function.
+<file pascal>
+/// <summary>
+/// Test Scripting Unit
+/// </summary>
+unit app.test;
+interface
+const
+	DEFAULT_STR : String = 'Test' + '-Output-' + 'Test:';
+type
+	TTest = class
+	[...]
+	end;
+implementation
+{ TTest }
+constructor TTest.Create();
+begin
+	inherited Create();
+	// use property test
+	Self.FieldBool := true;
+	Self.FFieldStr := 'Hello World';
+	Self.FFieldInt := 124;
+	Self.FFieldDbl := 1.25;
+	Self.FFieldObj := Self;
+end;
+destructor TTest.Destroy();
+begin
+	inherited Destroy();
+end;
+function TTest.GetFieldBool() : Boolean;
+begin
+	Result := Self.FFieldBool;
+	System.WriteLn('TTest.GetFieldBool() called');
+end;
+procedure TTest.SetFieldBool(AValue : Boolean);
+begin
+	Self.FFieldBool := AValue;
+	System.WriteLn('TTest.SetFieldBool() called');
+end;
+class function TTest.GetDefaultStr() : String;
+begin
+	Result := DEFAULT_STR;
+end;
+procedure TTest.Output(AIdx : Integer);
+var LTmpStr : String;
+    LSeed : Single;
+begin
+    LSeed := System.RandomFloat();
+	LTmpStr := TTest.GetDefaultStr() +
+		'Object{' +
+		'"fieldStr":"' + Self.FFieldStr +
+		'", "fieldInt":"' + Self.FFieldInt.ToString() +
+		'", "fieldDbl":"' + Self.FFieldDbl.ToString() +
+		'", "fieldBool":"' + Self.FieldBool.ToString() +
+		'", "fieldObj":"' + Self.FFieldObj.ToJSON() +
+		'"}';
+	LTmpStr := AIdx.ToString() + #9' [' + LSeed.ToString() + ']'#9#9 + LTmpStr +
+		' => ' + Self.Calculate(AIdx * 0.5).ToString();
+	System.WriteLn(LTmpStr);
+end;
+function TTest.Calculate(AFactor : Double) : Double;
+begin
+	Result := Self.FFieldInt.ToDouble() + Self.FFieldDbl * AFactor;
+end;
+end.
+</file>
 ==== Native ====