This is a restart of the lengthy thread in "Re: so what about switch()"
about inclusive vs exclusive slice ending.
OddesE proposed the [ 2 .. 4 ) end-exclusive syntax and [ 2 .. 4 ]
end-inclusive syntax but it can be confused with a missing closing ] if the
expression appears inside () or if the the slice boundaries are
parenthesized expressions (particularly the second one).
Why not [ 2 .. 4 -] for an end-exclusive slice, -] being a single token ? Or
perhaps <] instead of -].