On Tue, Sep 8, 2015 at 5:28 PM, Volkert <volkert@komponentenwerkstatt.de> wrote:

Would it be nicer to open a Alert box?

Yes. Now maybe it should not be done directly from here...

�� SlotClassBuilder >> category: aCategory

�� aCategory isEmpty ifTrue: [ InvalidPackageName signal: 'The Category should not be empty' ].

�� category := aCategory��

...since that might(?) introduce a dependency from the kernel to the UI. But maybe further down the stack in one of...

�� PackageTreeNautilusUI(AbstractNautilusUI)

�� >> compileAClassFrom: aString notifying: aController

�� >>��compileSource: aText notifying: aController

there could be an error handler. Would you like to have a go at it?

cheers -ben