> but what's that cabbage thing before $c? It's the Atomic Symbol, U+269B. (Tangent: when looking up that unicode value, I learned that Unicode puts the atomic symbol in the Religious Symbols subcatigory. Slightly troubling!)
Here, it's being used as part of the atomic prefix increment operator, https://docs.raku.org/type/atomicint#prefix_++⚛ (As Vadim already mentioned). That operator is exactly like the regular prefix ++, except that it's guaranteed to avoid race conditions in multithreaded use. It's appropriate to use with Junctions, because they're theoretically multitheadable. On the other hand, they *aren't* yet multithreaded in any implementation, so for now my $c = 0; sub foo($) { ++$c }('a'|'b,b'|'c'); say $c; works just as well (though the semantics are technically wrong!) > Also worth noting that the hyper-op is needed here because pointy blocks are > not auto-threaded > over junctions and take them as-is Interesting – I didn't realize that. Is the hyper op the only thing that triggers auto-threading for Blocks? Here's a slightly different take on the same basic idea, which avoids leaking $c: {my atomicint $len; sub ($) { ++⚛$len }($_); $len}('a'|'b,b'|'c') May 24, 2021 10:11 AM, "Andy Bach" <andy_b...@wiwb.uscourts.gov> wrote: > my atomicint $c = 0; > sub foo($) { ++⚛$c }('a' | 'b,b' | 'c'); > say $c; > > I was sort of hanging on by my fingertips (this completely lost me: > >> Or, taking about tricks: > > ('a' | 'b,b' | 'c')».&(-> $ { ++⚛$c }); > > ) but what's that cabbage thing before $c? Oh, and WAT is" Weird/will Ass > Thing"? > > _______________________________ > > From: Vadim Belman <vr...@lflat.org> > Sent: Monday, May 24, 2021 8:53 AM > To: perl6-users <perl6-us...@perl.org> > Subject: Re: File::Find using a junction with exclude > CAUTION - EXTERNAL: > > Still ugly but much more reliable trick would be to use a sub and a counter > variable: > > my atomicint $c = 0; > sub foo($) { ++⚛$c }('a' | 'b,b' | 'c'); > say $c; > > Or, taking about tricks: > > ('a' | 'b,b' | 'c')».&(-> $ { ++⚛$c }); > > Apparently, this one is not ugly by semantics, but by its notation too. Also > worth noting that the > hyper-op is needed here because pointy blocks are not auto-threaded over > junctions and take them > as-is: > > -> $v { say $v.WHAT }(1|2); # (Junction) > > Best regards, > Vadim Belman > >> On May 24, 2021, at 8:42 AM, Daniel Sockwell <dan...@codesections.com> wrote: > > It can be done without the EVAL: > > any('a', 'b', 'c').raku.substr(4, *-1).split(',').elems > > 3 >> Yeah, but only at the cost of some fragility: > > any('a', 'b,b', 'c').raku.substr(4, *-1).split(',').elems >> 4 >> >> I suppose you could do: > > any('a', 'b,b', 'c').elems.raku.substr(4, *-1).split(',').elems >> 3 >> >> but I'm not sure that's _that_ much better than EVAL – either way, we're >> depending on the Str >> representation of inherently non-Str data, which seems like the main sin of >> EVAL. >> >> – codesections > > CAUTION - EXTERNAL EMAIL: This email originated outside the Judiciary. > Exercise caution when > opening attachments or clicking on links.
