FWD » Core Development » User Interface

The trigger, associated with a button is not converted.

The 4gl:

main.p

DEFINE FRAME theFrame
   WITH SIZE 30 BY 10.

DEFINE BUTTON applyFormat LABEL "Apply" 
  TRIGGERS:
    ON CHOOSE DO:
       MESSAGE "Hello".
    END.
  END TRIGGERS.

ENABLE applyFormat WITH FRAME theFrame.

VIEW FRAME theFrame.
WAIT-FOR GO OF FRAME theFrame.

The conversion result (no trace of the trigger code):

package com.test3820;
import com.goldencode.p2j.util.*;
import com.test3820.ui.*;
import com.goldencode.p2j.ui.*;
import static com.goldencode.p2j.util.BlockManager.*;
import static com.goldencode.p2j.util.InternalEntry.Type;
import static com.goldencode.p2j.ui.LogicalTerminal.*;

/**
 * Business logic (converted to Java from the 4GL source code
 * in main.p).
 */

public class Main
{
   MainTheframe theframeFrame = GenericFrame.createFrame(MainTheframe.class, "theFrame");

   /**
    * External procedure (converted to Java from the 4GL source code
    * in main.p).
    */

   @LegacySignature(type = Type.MAIN, name = "main.p")

   public void execute()

   {
      externalProcedure(Main.this, new Block((Body) () -> 
      {
         theframeFrame.openScope();
         FrameElement[] elementList0 = new FrameElement[]
         {
            new WidgetElement(theframeFrame.widgetApplyFormat())
         };
         theframeFrame.enable(elementList0);
         theframeFrame.view();
         LogicalTerminal.waitFor(theframeFrame, new EventList("GO", theframeFrame.asWidget()));
      }));
   }
}

In OW the 4gl above works as expected: pressing the button prints "Hello".

I guess this is related to the TRIGGERS phrase which is not as commonly used as the ON statement.

As a workaround, just move the trigger outside of the triggers phrase and into an ON statement.

ON CHOOSE OF applyFormat DO:
   MESSAGE "Hello".
END.

Greg Shah wrote:

I guess this is related to the TRIGGERS phrase which is not as commonly used as the ON statement.

As a workaround, just move the trigger outside of the triggers phrase and into an ON statement.

[...]

Yes, if I rewrite the example as following, it compiles and works as expected:

DEFINE BUTTON applyFormat LABEL "Apply".

DEFINE FRAME theFrame
   applyFormat
   WITH SIZE 30 BY 10.

ON CHOOSE OF applyFormat
DO:
   MESSAGE "Hello".
END.

ENABLE applyFormat WITH FRAME theFrame.

VIEW FRAME theFrame.
WAIT-FOR GO OF FRAME theFrame.

The problem is most likely in rules/annotations/triggers_phrase_rewrite.rules. This code:

      <!-- ON phrase for a trigger inside a TRIGGERS block of a CREATE WIDGET/BROWSE

      Rewrites

      TRIGGERS                           STATEMENT
         ON                                 ON
            EVENT_LIST                         OF
               EVENT             to               EVENT_LIST
            TRIGGER_BLOCK                            EVENT
                                                  WIDGET_LIST
                                                     VAR_HANDLE
                                               TRIGGER_BLOCK
      -->
      <rule>relativePath("STATEMENT/CREATE_WIDGET/KW_TRIGGERS/KW_ON") or
            relativePath("STATEMENT/CREATE_BROWSE/KW_TRIGGERS/KW_ON")
...

Notice that it only processing for CREATE <widget> and CREATE BROWSE cases. It ignores other cases. Searching for trigger_phrase in progress.g shows that it can be matched in the following other constructs: DEFINE VARIABLE, DEFINE BUTTON, DEFINE RECTANGLE and in the menu item phrase of a DEFINE MENU or DEFINE SUB-MENU.

The solution is to add cases to the above matching logic and to make some modifications to the re-parenting code for the "non-handle" statement cases.