[Python-ideas] Allow lambda decorators
tjreedy at udel.edu
Mon Feb 9 07:03:39 CET 2009
Carl Johnson wrote:
> A few months back there was a discussion of how code like this gives
> "surprising" results because of the scoping rules:
And solutions were given.
> >>> def func_maker():
> ... fs = 
> ... for i in range(10):
> ... def f():
> ... return i
> ... fs.append(f)
> ... return fs
> >>> [f() for f in func_maker()]
> [9, 9, 9, 9, 9, 9, 9, 9, 9, 9]
> Various syntax changes were proposed to get around this, but nothing
> ever came of it.
a) there is already a trivial way to get the result wanted;
b) proposals are wrapped in trollish claims;
c) perhaps no proposer is really serious.
To me, one pretty obvious way to define default non-parameters would be
to follow the signature with "; <name = expr>+". Where is the PEP, though?
> Thinking about it some more, I've realized that the change I proposed is
> unnecessary, since we already have the decorator syntax. So, for
> example, the original function can be made to act with the "expected"
> scoping by using an each_in function defined as follows:
Such a mess to avoid using the current syntax
Like Guido, my head hurt trying to read it, so I quit.
> What do other people think?
Terry Jan Reedy
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