Thomas Lee wrote:
In porting one of the old peephole optimizations to the new AST compiler
I noticed something weird going on with the following code:
a, b, c = 1, 2, 3
Now, as you would expect this gets parsed into an Assign node. That
Assign node looks like the following:
Assign.targets = [Tuple(Name(a), Name(b), Name(c))]
Assign.value = Tuple(1, 2, 3)
What's weird here is that Assign.targets is an asdl_seq ... why are we
wrapping the names in a Tuple() node? Shouldn't it look something more
like this:
Assign.targets = [Name(a), Name(b), Name(c)]
I understand that parsing the testlist might yield a tuple and it was
thus easier to just use the tuple rather than unpack it into an asdl_seq
... but if this was the intention, then why is Assign.targets an expr*
rather than a plain old expr?
I haven't looked at that code recently, but I believe the ADSL sequence
in the assignment node is for statements where there are actually
multiple assignment targets, such as:
>>> p = x, y = 1, 2
>>> p, x, y
((1, 2), 1, 2)
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://www.boredomandlaziness.org
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