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Dynamic Interface

I would like a way in AS3 to define an interface as being dynamic. In some cases I want all classes that implement an interface to also have to be dynamic. Why might this be useful? I find the chained property accessors much nicer to deal with. I'm not as concerned about adding new methods to the interface and some of the other stuff that you can do with a dynamic class, I just want easy access to unspecified attributes. The fact that you can still use the associative array style lookup on an interface to get the same result only strengthens my belief that you should be able to mark an interface as dynamic.

Since you can't apply the dynamic keyword to an interface and there doesn't seem to be a system interface that endows dynamicness on an interface, you are forced to either use looser typing or use the alternative syntax. I think this calls for an example.

Say I have this interface defined:


package com.example {
public interface ISample {}
}

In another class I have a method that uses that interface:


package com.example {
public class UseSample {
public function displayProp(sample:ISample):void {
trace(sample.prop);
}
}
}

That generates the lovely compiler error:
1119: Access of possibly undefined property prop through a reference with static type com.example:ISample.

If you change the code to use array syntax it will compile:


package com.example {
public class UseSample {
public function displayProp(sample:ISample):void {
trace(sample["prop"]);
}
}
}

In my mind the array syntax is much more obtuse. Oh well, I can always hope :)

Tags: actionscript as3 flex programming

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