perl6

Does Perl 6 have a built-in tool to make a deep copy of a nested data structure? Added example: my %hash_A = ( a => { aa => [ 1, 2, 3, 4, 5 ], bb => { aaa => 1, bbb => 2 }, }, ); my %hash_B = %hash_A; #my %hash_B = %hash_A.clone; # same result %hash_B<a><aa>[2] = 735; say %hash_A<a><aa>[2]; # says "735" but would like get "3" my %A = ( a => { aa => [ 1, 2, 3, 4, 5 ], bb => { aaa => 1, bbb => 2 }, }, ); my %B = %A.deepmap(-> $c is copy {$c}); # make sure we get a new container instead of cloning the value dd %A; dd %B; %B<a><aa>[2] = 735; dd %A; dd %B; Use .clone and .deepmap to request a copy

use java::util::zip::CRC32:from<java>; my $crc = CRC32.new(); for 'Hello, Java'.encode('utf-8') { $crc.'method/update/(B)V'($_); } say $crc.getValue(); sadly, this does not work Method 'method/update/(B)V' not found for invocant of class 'java.util.zip.CRC32' This code is available at the following links. It is the only example I've been able to find Rakudo Perl 6 on the JVM (slides) Perl 6 Advent Calendar: Day 03 – Rakudo Perl 6 on the JVM Final answer Combining the code cleanups explained in the Your answer cleaned up section below with Pepe Schwarz's improvements mentioned in the

I've been looking at the various ways of constructing lazy lists in Perl 6 and I would like to collect all of the concise ways of describing the Fibonacci sequence. I will start this off with the three from masak 's journal: my @fibs := (0, 1, -> $a, $b { $a + $b } ... *); my @fibs := (0, 1, { $^a + $^b } ... *); my @fibs := (0, 1, *+* ... *); I was thinking something like this would also work, but I think I have the syntax wrong: my @fibs := (0, 1, (@fibs Z+ @fibs[1..*])); Something there is eager (the slice?) and causes Rakudo to enter an infinite loop. It's a translation of the Haskell

Parrot is the virtual machine originally designed for Perl 6. What technical capabilities does the Parrot VM offer that competing virtual machines such as the Java Virtual Machine (JVM) / Hotspot VM and Common Language Runtime (CLR) lack? Schwern The following answer was written in 2009. See also this 2015 update by raiph . To expand on @Reed and point out some highlights, Parrot's opcodes are at a far higher level than most virtual machines. For example, while most machines store integers and floats, the basic registers are integers, numbers, strings and Parrot Magic Cookies (PMCs). Just

Perl 6 seems to have an explosion of equality operators. What is =:= ? What's the difference between leg and cmp ? Or eqv and === ? Does anyone have a good summary? =:= tests if two containers (variables or items of arrays or hashes) are aliased, ie if one changes, does the other change as well? my $x; my @a = 1, 2, 3; # $x =:= @a[0] is false $x := @a[0]; # now $x == 1, and $x =:= @a[0] is true $x = 4; # now @a is 4, 2, 3 As for the others: === tests if two references point to the same object, and eqv tests if two things are structurally equivalent. So [1, 2, 3] === [1, 2, 3] will be false

I am trying to parse a csv file, and I am trying to access names regex in proto regex in Perl6. It turns out to be Nil. What is the proper way to do it? grammar rsCSV { regex TOP { ( \s* <oneCSV> \s* \, \s* )* } proto regex oneCSV {*} regex oneCSV:sym<noQuote> { <-[\"]>*? } regex oneCSV:sym<quoted> { \" .*? \" } # use non-greedy match } my $input = prompt("Enter csv line: "); my $m1 = rsCSV.parse($input); say "==========================="; say $m1; say "==========================="; say "1 " ~ $m1<oneCSV><quoted>; # this fails; it is "Nil" say "2 " ~ $m1[0]; say "3 " ~ $m1[0][2]; Thank you

That's what I'm trying to do. > my sub nplus1($n) {$n +1} > my regex nnplus1 { ^ (\d+) &nplus1($0) $ } > "123" ~~ &nnplus1 P6opaque: no such attribute '$!pos' in type Match... The <{...}> construct runs Perl 6 code inside a regex, and evaluates the result as a regex: my sub nplus1($n) {$n +1} my regex nnplus1 { ^ (\d+) <{ nplus1($0) }> $ } say so '23' ~~ &nnplus1; # Output: True say so '22' ~~ &nnplus1; # Output: False Keep in mind that regexes are subs. So don't call your matcher a sub —be more specific and call it a regex . Yes, you can pass arguments to regex / token / rule . It's really