[Python-Dev] more timely detection of unbound locals (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Mon May 9 17:22:36 CEST 2011

On Tue, May 10, 2011 at 1:06 AM, Eli Bendersky <eliben at gmail.com> wrote:

It probably shows the original complaint even more strongly. As for being a problem with the suggested solution, I suppose you're right, although it doesn't make it much different. Still, before a possible assignment to 'x', it should be loaded as LOADNAME since it was surely not bound as local, yet.

Yeah, I've decided I'm happier with the closure based arguments than the conditional statement related ones. "Assignments create local variables" is a relatively simple rule to reason about, and is equally valid for the current scope and for any nested scopes. The symtable analysis for nested scopes is ordering independent (and can't be changed for backwards compatibility reasons if nothing else), and UnboundLocalError is a natural outgrowth of applying those semantics to the current scope as well.

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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