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Howto:Troubleshooting Nasal Callbacks: Difference between revisions
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Howto:Troubleshooting Nasal Callbacks (view source)
Revision as of 19:15, 31 January 2016
, 31 January 2016→Background
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{{FGCquote | {{FGCquote | ||
|1= Someone recently pointed out that the setlistener() / removelistener() API makes it easy to leak resources. So I wondered about making an alternate API where the return value from setlistener '''must''' be kept, or the listener is removed. I can imagine this with a helper object | |1= Someone recently pointed out that the setlistener() / removelistener() API makes it easy to leak resources. So I wondered about making an alternate API where the return value from setlistener '''must''' be kept, or the listener is removed. I can imagine this with a helper object | ||
<syntaxhighlight lang="nasal"> | |||
var myL = setlistener2("some/prop", func { ... }} ) | var myL = setlistener2("some/prop", func { ... }} ) | ||
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myL.addprop("yet/another/prop"); | myL.addprop("yet/another/prop"); | ||
</syntaxhighlight> | |||
Now you need to retain a ref to myL or the listeners on all the props are removed. I don't think we can retro-fit this to the existing API, because I suspect many places just ignore the return value and would break with this change. | Now you need to retain a ref to myL or the listeners on all the props are removed. I don't think we can retro-fit this to the existing API, because I suspect many places just ignore the return value and would break with this change. | ||
(Or even pass a vec of property names to setlistener2, to avoid all the discrete calls to 'addprop', that's a seperate detail really) | (Or even pass a vec of property names to setlistener2, to avoid all the discrete calls to 'addprop', that's a seperate detail really) | ||