[IronPython] def within a def

Alcides Fonseca me at alcidesfonseca.com
Thu Dec 11 01:38:49 CET 2008

Em 2008/12/11, às 00:33, Artie Ziff escreveu:

> Looking at the examples on the "IronPython & Windows Forms" page, I  
> see
> a code that I am not familiar. In the 2nd example on this page,
> <http://www.voidspace.org.uk/ironpython/winforms/part5.shtml>, I am
> unfamiliar with placing a method (in this case "update") inside a
> constructor.
> I see that the method "update" is being added to the button's event
> handler in the constructor, __init__. Why must this method be defined
> inside the constructor? Is there a name for this? Is this an example  
> of
> a PEP 309, Partial Function Application?

Actually, it's not a method. Methods take self as the first argument.  
that update is just a function that takes two parameters and prints  
some value. It's the callback of that event.

After you call

self.button1.Click += update

Everytime button1 is clicked, it is going to call the function update.

You can define functions anywhere in your code, inside classes, inside  
other functions, at the module level, etc... Methods are the ones that  
are restricted to be inside the class and taking self as the first  


* Actually you can monkey patch, but that's an advanced feature.

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