[Python-3000] Set literal

[Mark Summerfield]

On 2008-01-25, Guido van Rossum wrote:
> For the record, I'm thinking Raymond has won this argument fair and
> square, and I'm withdrawing my opposition.
>
> I hope it isn't too confusing that {1: 1} creates a *mutable* dict
> while {1} creates an *immutable* frozenset. I still find this slightly
> inelegant. But the practicality of being able to treat set literals as
> compile-time constants wins me over.

So this will produce:

    frozenset()	# empty frozen set
    {1}	    	# 1 item frozen set
    {1, 2}  	# 2 item frozen set
    {}	    	# empty dict
    {1:1}   	# 1 item dict
    {1:1, 2:2}	# 2 item dict

I think this is confusing and messy, especially for new Python programmers.

If you're going to make the change, why not make things consistent:

    {}		# empty frozen set
    {1}	    	# 1 item frozen set
    {1, 2}  	# 2 item frozen set
    {:}	    	# empty dict
    {1:1}   	# 1 item dict
    {1:1, 2:2}  # 2 item dict

-- 
Mark Summerfield, Qtrac Ltd., www.qtrac.eu