Mailing List Archive: 49091 messages
  • Home
  • Script library
  • AltME Archive
  • Mailing list
  • Articles Index
  • Site search

[REBOL] Re: Enage and Select

From: greggirwin:mindspring at: 17-Sep-2003 9:44

Hi Matt, MM> But what if I want to extend the functionality of a specific handler? MM> for instance, if I wanna keep the highlighting functionality, and also have MM> auto-scroll when the user clicks and drags off the face? Both would be MM> handled by the over and away actions. If I'm reading the last responce to MM> this correctly, the idea is to copy the old engage function into a new MM> function, then make a new engage function. Then call the appropriate engage MM> function based on the action you are trying to handle. Am I right? Is this MM> possible, or am I just asking too much? What Romano posted shows how you can create your own and then "pass along" events to the original handler by calling it from your function. Depending on what you're doing, there may be issues with that approach. This is not a REBOL thing, but applies to any system where you try to inherit and extend functionality. The original code has no idea what you're doing, so it expects things to be as they were. For example, the swiping/highlighting code may expect the start position to be visible on the screen, but if you drag down and auto-scroll, it isn't anymore. There may be interactions that you have to account for between your new stuff and what's there already. There may also be times where you need to call the base function before or after your code, but not always one or the other. That is, depending on what you're doing, you may need to decide whether to do the work first, or call the base function first and then do your work. Of course, you can always try it and see what happens. Sometimes things just magically seem to do what you want. :) -- Gregg