On Thu, May 26, 2016 at 12:43 PM, Ethan Furman <ethan@stoneleaf.us> wrote:
I'll meet you halfway:
{a, b} = some_dict
which is currently a SyntaxError, so little backwards compatibility concerns, plus it clearly state the mapping should have two elements, similarly to
[a] = some_iterable
and
(b) = some_iterable
both clearly state that a one-element iterable is being unpacked.
Careful - the second one doesn't:
(b) = [1, 2, 3]
Parens don't make a tuple, and that includes with unpacking. You'd be correct if you had a comma in there, though. I hope there doesn't end up being a confusion between mapping unpacking and set display. Sets are a bit of an odd duck; are they like lists only unordered, or like mappings only without values? I've seen them used both ways, and the syntax is somewhere between the two. Having a syntax that constructs a set if used on the RHS but unpacks a dict if used on the LHS seems to violate syntactic purity, but I'd be happy to let practicality trump that. ChrisA