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[REBOL] layout within an object

From: mgh520::yahoo at: 30-Jul-2001 21:52

I got this tip from the REBOL/View developer's guide. It suggest defining a layout inside of an object to keep variables local and avoid confusion. I like this approach as it seems clean. However, in the script at the end of this email, an instance variable (name) gets set after the object is created, and if you "print myview/name" you get the value you'd expect, i.e., Nelson Muntz. But once the view is displayed, if you click the Print button, it will print the original value of the variable, Edna Crabapple. It seems like the block for the Print button action is being evaluated when it's created and then not evaluated again when it's actually clicked. I figured out that if I wrap the layout definition inside of a block [layout [size 640x480 ....] then I can use view do [myview/page-layout] and get the correct results, which I believe further supports my theory that the action is being evaluated once at the start. According to the developer's guide, you can wrap things in a layout with a do [...] to cause them to be evaluated once at creation time. But this really seems to be the default. Can anyone explain this behavior or should I just use the block techinque? What I haven't show yet, is what the value of name is once the view is closed. But I didn't know how to do that--I'm still new at this. Thanks in advance for any help. I hope to learn enough soon to be able to answer other's questions, as everyone has been so helpful on this list. Thanks. Mike REBOL [] MyObject: make object! [ name: "Edna Crabapple" page-layout: layout [ size 640x480 below h2 "Test" return button "Print Value" [print ["name in button action:" name]] ] ] myview: make MyObject [] myview/name: "Nelson Muntz" print myview/name view myview/page-layout