Hello,
Nice to have some flexibility on acceptable punctuations for grouping
and index elements. Though at this point, I just want to remember which
punctuation definitively will work for which group type in all
situations.

Punctuations
[..]
(..)
{..}
<..>

Group type
set creation and index
hash creation and index
array creation and index
and slicing a string?

I could be missing other punctuations or group types.

Thanks for the help.
gk