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Postings from September 2005
Dave Whipp wrote:
> Imagine you're writing an implementation of the unix "uniq" function:
>
> my $prev;
> for grep {defined} @in -> $x {
> print $x unless defined $prev && $x eq $prev;
> $prev = $x;
> }
>
> This feels clumsy. $prev seems to get in the way of what I'm trying to
> say. Could we imbue optional binding with the semantics of not being
> consumed?
>
> for grep {defined} @in -> $item, ?$next {
> print $item unless defined $next && $item eq $next;
> }
>
> The same behavior, but without the variable outside the loop scope.
>
>
> It would also be good not to overload the meaning of $?next to also
> tell us if we're at the end of the loop. In addition to FIRST{} and
> LAST{} blocks, could we have some implicit lexicals:
>
> for @in -> $item, ?$next {
> print $item if $?LAST || $item ne $next
> }
>
I like the idea. There's no reason the view window and the consumption
have to be the same.
=Austin
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