Tkinter Menus

[Tim Daneliuk]

Justin Shaw wrote:
<SNIP>
> 
> 
> This version invokes callback when the menu is created:
> m.add_command(label='Call %s' % (label=" ...",  callback(i+1))
> 
> and so is essentially the same as
> m.add_command(label='Call %s' % (label=" ...",  None)
> 
> as apposed to the other version which creates a lambda function at menu
> creation time that gets called when the menu is clicked.


Yes, that's what I suspected.  But, what I'm trying to understand is
the language semantics here:  *why* do the two forms behave the way
they do -i.e., What is it about the lambda form that defers
execution until the time when a menu item is selected?


-- 
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Tim Daneliuk
tundra at tundraware.com