Delphi Callbacks/Function Pointers

While working on a legacy Delphi project recently at work,  the need arose to use a callback which Delphi makes surprisingly easy.

Define the type:

type
  TCallBackProc = procedure(paramOne : string) : of object;

Call:

procedure ExecCallBack(callBack : TCallBackProc)
begin
  callBack('test');
end;