Scope of variables passed to function handles?

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

Answer 1

[matt dash]

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.

[Adam]

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]

Thanks guys.

This is actually a very neat feature.

It makes dependency-inject and functional programming a lot simpler.