Type
  interval_type         = [long] (weekly, fortnightly, monthly, bimonthly, quarterly, half_yearly, yearly);
  field_type            = [long] (principal, rate, payment);

Var
  input_fields          : array [principal..payment] of record
                            widget : Dwt$Widget;
                            name   : varying [30] of char;
                          end;
  list_box              : Dwt$Widget;
  selected_interval     : interval_type := monthly;


  { Repayment Interval menu }
  Procedure Set_Interval (widget: Dwt$Widget; interval: interval_type; reason: Dwt$Any_CB_St);
  begin
  writeln ('in Set_Interval; selected interval = ', interval);
  selected_interval := interval;
  end;

  { Tracewrite }
  Procedure Text_Value_Changed (widget: Dwt$Widget; field: field_type; reason: Dwt$Any_CB_St);
  begin
  writeln('in Text_Value_Changed; field = ',field);
  end;

  { Quit button }
  Procedure Quit;
  begin
  writeln('in Quit');
  goto Exit;
  end;

  { List Box }
  Procedure Create_List_Box (widget: Dwt$Widget);
  begin
  writeln('in Create_List_Box');
  list_box := widget;
  end;

  { Text Input Fields }
  Procedure Create_Data_Field (widget: Dwt$Widget; f: field_type; reason: Dwt$Any_CB_St);
  begin
  writeln('in Create_Data_Field');
  input_fields[f].widget := widget;
  end;