Thus spake Gregory Bond ([EMAIL PROTECTED]): > Paul Rubin wrote: > > > > > def FunctionMaker(avar, func, label): > > def callback(): > > avar.set(label) > > func() > > return callback > > I've seen this idiom a lot and I know _what_ it does..... > but I can't > work _how_ it does it. How does the name binding work so > that "avar" in > the returned function still references the object passed > into the > (long-distant!) FunctionMaker() call? > > Web pages / turotial ptrs etc gladly accepted.
The lexical scope within which a function is declared is made available to the function when it is run. This is done by storing the values of free variables within the declared function in the func_closure attribute of the created function object. If you want to read more, the keyword you're looking for is "closure" - a quick search on Google for "python closure" should satisfy your curiosity handily. There is also a neat recipe for inspecting the values kept in the func_closure attribute of function objects directly: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/439096 Cheers, Aldo -- Aldo Cortesi [EMAIL PROTECTED] http://www.nullcube.com Off: (02) 9283 1131 Mob: 0419 492 863 -- http://mail.python.org/mailman/listinfo/python-list
