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628 :: on_raise feature

• PV (orginal) [2014-11-13T19:55:33+01:00] view original

  What are use cases for this feature? At the moment when it gets invoked the bad already happened and unless the current exception keeps track of every runtime detail (and these details would be mostly unusable in standard exceptions handlers) there's very little what one can do. It is not possible to restart the function automatically or debug the code easily like they do in Lisp. Current implementation can even use only one installed handler.

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• Araq (orginal) [2014-11-13T20:25:28+01:00] view original

  The use case I had in mind is for hacking together a script, so that stack traces can be converted into simpler messages and then it can simply quit. I never used it for that though. Attaching it to a 'try' handler instead would possible too but then you might as well use finally or except. Also the onRaise handler creates a loophole for the effect system. At this point we should simply deprecate it and then remove it.

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• Araq (orginal) [2014-11-16T15:00:00+01:00] view original

  Er .. what I wrote makes no sense. I confused system.onRaise with system.globalRaiseHook. system.onRaise was an attempt to get a Lisp-like condition system. But I don't like these anymore, it's usually a better idea to give the parser an explicit onError hook.

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