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   ► KBTo/From GuidesDelphiData Structures  Print This     

Custom Routines (Cross Ref > Data Structures)

By Mike Prestwood

Delphi versus Access VBA: A side by side comparison between Delphi and Access VBA.

 
Language Details
 

Language Details is kind of a catch all for stuff that didn't make it into language basics nor any other category.

Custom Routines

[Other Languages] 

Languages Focus

For non-OOP languages, a custom routine is a function, procedure, or subroutine and for pure OOP languages, a custom routine is a class method. Hybrid languages (both non-OOP and OOP) combine both.

Delphi:   procedure, function

Delphi is a hybrid language so you can create either class methods (functions and procedures) or you can create global functions and procedures. When a function or procedure is part of a class, it is a class method.

[function/procedure] RoutineName : ReturnType;

As with C++, your custom routine must come before it's first usage or you have to prototype it in the Interface section.

Note: Contrast Delphi with Delphi Prism which is an OOP language (everything is within a class). Both Delphi and Delphi Prism are based on Object Pascal but implement OOP features differently and have some syntax differences too.

Syntax Example:
procedure SayHello(pName: String);
begin
  ShowMessage('Hello ' + pName);
end;
 
function Add(p1, p2 : Double): Double;
begin
  Result := p1 + p2;
end;
Access VBA:   Sub, Function

Access VBA is a non-OOP language with some OOP features. It offers both Subs and Functions. A Sub does not return a value while a Function does. When Subs and Functions are used in a class module, they become the methods of the class.

Syntax Example:
Sub SayHello(ByVal pName As String)
  MsgBox ("Hello " & pName)
End Sub
 
Function Add(pN1 As Integer, pN2 As Integer) As Integer
  Add = pN1 + pN2
End Function













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