raku

问题 Given the documentation and the comments on an earlier question, by request I've made a minimal reproducible example that demonstrates a difference between these two statements: my %*SUB-MAIN-OPTS = :named-anywhere; PROCESS::<%SUB-MAIN-OPTS><named-anywhere> = True; Given a script file with only this: #!/usr/bin/env raku use MyApp::Tools::CLI; and a module file in MyApp/Tools called CLI.pm6: #PROCESS::<%SUB-MAIN-OPTS><named-anywhere> = True; my %*SUB-MAIN-OPTS = :named-anywhere; proto MAIN(|)

问题 I'm implementing a simple linked list and to denote the fact that there is no next node, I'm using the value Nil . The thing is that when assigned to a container, Nil will attempt to revert the container to its default value which means I need to use the container's default value or Any to determine if the linked list's end has been reached. However, I'd still like to use Nil (if only for its clear intent) and no other value to test for the non-existence of a next node in the code (e.g.,

问题 I am learning Perl6 from Perl5. I am looking at the adverb :exists https://docs.perl6.org/type/Hash#:exists but there isn't a :defined adverb but I am concerned because there is a distinction between perl5's exists & defined : What's the difference between exists and defined? How can I do something like this in Perl6? if (defined $hash{key}) { $hash{key}++; } else { $hash{key} = 1; } 回答1: if defined %hash{'key'} { %hash{'key'}++; } else { %hash{'key'} = 1; } Use the defined routine or method.

问题 I am trying to add «€» as an alias for the «$» scalar, and doing it with a Slang is the way to do it I think. But perl6.doc doesn't mention Slangs at all. I have read the following: https://perlgeek.de/en/article/mutable-grammar-for-perl-6 (from 2008) https://mouq.github.io/slangs.html And looked at the Slang::Roman and Slang::Tuxic modules. The result is this file (ScalarEU.pm6): use nqp; unit module ScalarEU2; sub EXPORT(|) { my role Euscalar { token sigil:sym<$> { '€' | '$' } } my Mu $MAIN

问题 This code: my $þor-blob = Blob.new("þor".ords); $þor-blob.decode( "ascii", :replacement("0"), :strict(False) ).say Fails with: Will not decode invalid ASCII (code point > 127 found)␤ And this one: my $euro = Blob.new("3€".ords); $euro.decode( "latin1", :replacement("euro") ).say Simply does not seem to work, replacing € by ¬. It's true that those methods are not tested, but is the syntax right? 回答1: TL;DR : Only samcv or some other core dev can provide an authoritative answer. This is my

问题 race divides operations on an iterable automatically into threads. For instance, (Bool.roll xx 2000).race.sum would automatically divide the sum of the 2000-long array into 4 threads. However, benchmarks show that this is much slower than if race were not employed. This happens even if you make the array bigger. This happens even as the non-autothreaded version gets faster and faster with each version. (Auto-threading also gets faster, but is still twice as slow as not using it.) So the

问题 race divides operations on an iterable automatically into threads. For instance, (Bool.roll xx 2000).race.sum would automatically divide the sum of the 2000-long array into 4 threads. However, benchmarks show that this is much slower than if race were not employed. This happens even if you make the array bigger. This happens even as the non-autothreaded version gets faster and faster with each version. (Auto-threading also gets faster, but is still twice as slow as not using it.) So the

问题 First of all: raku (perl6) is amazing. And so is Cro. It only took a week-end to fall in love. However now I stumble over something that must be extremely simple. If I use a slurpy parameter in a multiple dispatch MAIN this is recognized and works perfectly: multi MAIN( 'config', 'add', *@hostnames ) { However if I make this a non-slurpy array, this is either not recognized or I don't know how to provide it from the command line: multi MAIN( 'config', 'add', @hostnames ) { I would expect one

问题 Perl 6's shell sends commands to the "shell" but doesn't say what that is. I consistently get bash on my machine but I don't know if I can rely on that. $ perl6 -e 'shell( Q/echo $SHELL/ )' /bin/bash $ csh % perl6 -e 'shell( Q/echo $SHELL/ )' /bin/bash % zsh $ perl6 -e 'shell( Q/echo $SHELL/ )' /bin/bash That's easy enough on Unix when it's documented, but what about cmd.exe or PowerShell on Windows (or bash if it's installed)? I figure it's the cmd.exe but a documented answer would be nice.

问题 In Perl 5, if I want to see the contents of a hash, I can use Data::Show, Data::Dump, or Data::Dumper. For example: use Data::Show; my %title_for = ( 'Book 1' => { 'Chapter 1' => 'Introduction', 'Chapter 2' => 'Conclusion', }, 'Book 2' => { 'Chapter 1' => 'Intro', 'Chapter 2' => 'Interesting stuff', 'Chapter 3' => 'Final words', } ); show(%title_for); Which outputs: ======( %title_for )======================[ 'temp.pl', line 15 ]====== { "Book 1" => { "Chapter 1" => "Introduction", "Chapter 2