On Saturday, 2 June 2012 at 11:49:17 UTC, Dario Schiavon wrote:
Hi,
I just read some old threads about opDollar and the wish to
have it work for non zero-based arrays, arrays with gaps,
associative arrays with non-numerical indices, and so on. It
was suggested to define opDollar as the end of the array rather
than the length (and perhaps rename opDollar to opEnd to
reflect this interpretation), so that collection[someIndex ..
$] would consistently refer to a slice from someIndex to the
end of the collection (of course the keys must have a defined
ordering for it to make sense).
I'm just thinking, if we want to generalize slices for those
cases, shouldn't we have a symmetrical operator for the first
element of the array? Since the $ sign was evidently chosen to
parallel the regexp syntax, why don't we add ^ to refer to the
first element? This way, collection[^ .. $] would slice the
entire collection, just like collection[].
Until now, ^ is only used as a binary operator, so this
addition shouldn't lead to ambiguous syntax. It surely wouldn't
be used as often as the opDollar, so I understand if you oppose
the idea, but it would at least make the language a little more
"complete".
The problem I see with this, it would be a larger burden when
writing generic code. Libraries would have to be written to
compensate for those containers. I'd prefer that all containers
are simply zero-based, unless there's a need for negative indices
(i.e. pointers). I think random-access ranges may be intended to
be zero-based as well.
