Scope of variables passed to function handles?

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Dehuan
Dehuan 2014-12-16
评论： Dehuan 2014-12-16
Hi, everyone,
I want to ask about the non-input variables in function handles.
For example, following code returns h(1)=2.
b=1;
h=@(a)a+b;
clear b;
display(sprintf('h(1)=%d', h(1)));
Is this kind of usage safe and correct?
Dehuan

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matt dash
matt dash 2014-12-16
As far as i know, yes this is safe and correct. Any non-input variables pass their values to the function at the time the function handle was created. Subsequent changes to or clearing of those variables has no effect on the function.
  2 个评论
Adam
Adam 2014-12-16
Yes, this is correct. It is also why passing the handles structure, for example, in a GUIDE-based file to a callback is not a good idea, because a copy of the structure at the exact time the callback is set is hard-coded into the callback, irrespective of when it is called.
Dehuan
Dehuan 2014-12-16
Thanks guys.
This is actually a very neat feature.
It makes dependency-inject and functional programming a lot simpler.

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