On Sep 25, 2007, at 2:00 , Nick Ager wrote:
Armed with new knowledge of Traits gained from the excellent "Squeak By Example" I tried: Smalltalk allClasses select: [:each | each hasTraitComposition]
which gave:
an OrderedCollection(ActionSequence BalloonBezierSimulation BalloonEngine BalloonEngineConstants BasicRequestor Behavior BrowserProvider ....WorldMenuProvider XMLTokenizer ZipConstants ZipFileConstants)
However browsing to a random class say "ActionSquence", doesn't show any evidence of Trait composition. Is this a problem with the current browser?
No. #hasTraitComposition only checks if the traitCompositions variable is not nil - the composition may still be empty. Which can happen quite easily since that variable is lazily initialized by sending #traitCompositions.
This appears to be by design, the codebase is scattered with #hasTraitComposition checks. But missing only one occurrence where #traitCompositions is sent unguarded by #hasTraitComposition will get the variable populated. And it will never get reset to nil as far as I can tell.
- Bert -