On Mon Feb 22 14:43:21 2016, greg.lon...@infineon.com wrote:
>
> Current format for a lazily evaluated list:
>
> my $lazylist = (0, { $_ + 3 } ...^ * > 10);
>
> ^*> is incoherent line noise.
Thanks for trying out Perl 6.
In case this wasn't just a rant, the ^ here is tied to the sequence, and means
exclude the endpoint. For example, 1...^4 produces a three element sequence.
The * is a Whatever star, and is ubiquitous in Perl 6. It's a way to generate
a closure; * > 10 here means "something greater than 10". So altogether,
...^ * > 10 should read, a sequence up to , but not including, a value greater
than 10.
So, as it turns out, this isn't really a list that needs lazifying, it's only
got
4 elements: 0, 3, 6, 9. The 12 is greater than 10, so we take everything up to
but
not including it.
> Please consider making a builtin function that looks kind of like a
> "for loop" but is lazily evaluated.
>
> my $lazylist = lazy ($_=0; $_ <= 10; $_+=3);
>
> The syntax for a FOR() loop is well established and already has
> everything needed to define a lazy list.
> (start condition; end condition; increment condition)
In Perl 6, the C-style for loop you reference is spelled "loop".
loop (my $i = 0; $i < 10; $i++) { say $i } # prints out 0 to 9.
> Keep the line noise version if you want, but a lazy() function would
> be much more natural and intuitive for oddball situations and would
> need almost zero explanation.
Turns out we already have a "lazy". So this code works today.
my $lazylist = lazy loop (my $i=0; ; $i++) { $i };
say $lazylist[1000];
Rejecting ticket. I encourage you to checkout docs.perl6.org
and/or stop by on the irc channel if you have more questions.
--
Will "Coke" Coleda
