Re: 12 hackers hacking...
Not long ago, Mark J. Reed proclaimed...
> What's the consensus on how to do an idiomatic countdown loop? I used
> for [1..$n].reverse...
This: will work eventually:
for $n..1:by(-1) { ... }
This currently works in rakudo:
for (1..$n).reverse { ... }
Re: 12 hackers hacking...
On Thu, Dec 25, 2008 at 1:55 AM, Stephen Weeks wrote:
> Not long ago, Mark J. Reed proclaimed...
>> What's the consensus on how to do an idiomatic countdown loop? I used
>> for [1..$n].reverse...
>
> This: will work eventually:
>for $n..1:by(-1) { ... }
Cool.
> This currently works in rakudo:
>for (1..$n).reverse { ... }
No, it doesn't (r34384)
for (1..10).reverse { say $^i }
01 9 8 7 6 5 4 3 2 1
The list is flattened into a string and then reversed by character;
the body of the loop is executed only once. That's why I used the
square brackets in my version.
-
Mark J. Reed
Re: 12 hackers hacking...
Not long ago, Mark J. Reed proclaimed...
> On Thu, Dec 25, 2008 at 1:55 AM, Stephen Weeks wrote:
> > This currently works in rakudo:
> >for (1..$n).reverse { ... }
>
> No, it doesn't (r34384)
>
> for (1..10).reverse { say $^i }
> 01 9 8 7 6 5 4 3 2 1
>
> The list is flattened into a string and then reversed by character;
> the body of the loop is executed only once. That's why I used the
> square brackets in my version.
Looks like you found a regression. This has been fixed since r34393.
[swe...@kweh perl6]$ rakudo
> for (1..10).reverse { .say }
10
9
8
7
6
5
4
3
2
1
pop'ping from an emty Array
Both pugs and rakudo agree on this one: 21:44 <@moritz_> perl6: my (@a, @b); @a.push(@b.pop); say @a.elems 21:44 < p6eval> ..pugs, rakudo 34399: OUTPUT«1» pop'ping from an empty array returns an undef, which is then pushed onto @a. Wouldn't it be nice of @empty_list.pop (or .unshift) would return a Nil instead, so that in list context this is the empty array, and the operation @a.push(@b.pop) would always preserve (@a.elems + @b.elems)? Cheers, Moritz (and a happy new year to all Perl 6 hackers, designers, fans and followers).
