While at isSelfEvaluating, I wonder why we do not abuse {..} notation
a bit more.
Instead of printing 'aSet( 0 at 0 1 at 2 )'
we could just make it evaluate proof '{0 at 0. 1 at 2} asSet'

Of course, with limited stream, we take the risk of loosing trailing '
asSet' information.
So we can also print using a less nice but still evaluating 'Set
newFrom: {0 at 0. 1 at 2}'.

As a bonus, generalizing this behaviour might also eliminate a few
bytecodes and methods from the Kernel.

Same for storeOn:

What do you think ?