<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body text="#000000" bgcolor="#FFFFFF"> <div class="moz-cite-prefix">On 3/24/23 8:31 AM, Alexandre Rousseau via Cuis-dev wrote: </div> <blockquote type="cite" cite="mid:CAKmOayLAPDAqsubDRizoXhz_HZ=U3JmX=KV2y38D_FvAt8oiLA@mail.gmail.com"> <pre class="moz-quote-pre" wrap="">I'm trying to modify rather than subclass BoxedMorp, adding a new instance var to the class definition. This fails while Transcript reports what follows. I'm guessing that recompilation of BoxedMorph does not play well while a WorldMorph (a subclass of BoxedMorph itself) instance is running. What would be a way to work around this? Class reshaping: InnerTextMorph has some instance running #acceptContents. </pre> <blockquote type="cite"> <pre class="moz-quote-pre" wrap="">This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: InnerTextMorph has some instance running #processKeystrokeEvent:. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: InnerTextMorph has some instance running #processKeystrokeEvent:. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: InnerTextMorph has some instance running #keyStroke:. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: InnerTextMorph has some instance running #keyStroke:. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: HandMorph has some instance running #startKeyboardDispatch:. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: HandMorph has some instance running #processEventQueue. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: WorldMorph has some instance running #doOneCycleNow. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: WorldMorph has some instance running #handsDo:. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: WorldMorph has some instance running #doOneCycleNow. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: WorldMorph has some instance running #doOneCycle:. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: WorldMorph has some instance running #mainLoop. This CompiledMethod would become invalid. Class reshaping aborted. Class reshaping: WorldMorph has some instance running #mainLoop. This CompiledMethod would become invalid. Class reshaping aborted. </pre> </blockquote> <pre class="moz-quote-pre" wrap=""> </pre> <fieldset class="mimeAttachmentHeader"></fieldset> </blockquote> First, let me analyze that problem. Nearly every Morph you see on the screen – <tt>SystemWindow</tt> and thus <tt>BrowserWindow</tt> – is derived from <tt>BoxedMorph</tt>. Juan added save guards to Object>>#become:, because adding the target object of <tt>#become:</tt> might still have some active contexts on the stack and these active contexts refer to methods that where compiled for the source object of <tt>#bceome:</tt>. In your case the source object is the old class and the target object is the new class, with the added instance variable. If you will add the instance variable add the end, it would work out. Otherwise some morphic code in the running system will certainly crash. Now for ways around this mess: Do you really need an instance variable? Morphs also have properties, that should be used if the instance variable is <tt>nil</tt> for most morphs. Properties come in handy here, because the can be added at run-time. If you insist on adding instance variables, you have to add your variable with no morphic code on the stack, meaning you have to do it from the command line. There is a method <tt>Class>>#addInstVarName:</tt> that lets you add instance variables. You can use the <tt>-e</tt> command-line option to execute code from the command line. HTH, Gerald </body> </html>