1 / 127

$@%!»; – Perl 6

$@%!»; – Perl 6. Frank Blendinger. fbr@methodpark.de. 2013-10-21.

reese-fletcher
Download Presentation

$@%!»; – Perl 6

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. $@%!»; – Perl 6 Frank Blendinger • fbr@methodpark.de • 2013-10-21 This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/3.0/ or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA.

  2. Disclaimer 2

  3. 6 != 5 • »The Perl 6 design process is about keeping what works in Perl 5, fixing what doesn't, and adding what's missing. That means there will be a few fundamental changes to the language, a large number of extensions to existing features, and a handful of completely new ideas. These modifications, enhancements, and innovations will work together to make the future Perl even more insanely great – without, we hope, making it even more greatly insane.« • Damian Conway 3

  4. Perl Philosophy • TIMTOWTDO: There Is More Than One Way To Do It • DWIM: Do What I Mean • Keep easy things easy and hard things possibleslurp("filename").lines • Huffman coding • Common things → short name • Crazy stuff → long names • “Weird things should look weird” 4

  5. A Little Perl History • 1987: Perl 1.0, 1994: Perl 5.0, 2013-05-18: Perl 5.18 • 2000: Perl 6 project started • New language – no compatibility with Perl 5 • use v6; *.pl/.pm vs. *.p6 • Intended for friendly coexistence with Perl 5 (still developed) • Some Perl 6 features backported to Perl 5(say, given/when, ~~, various CPAN modules: Perl6::*) 5

  6. Perl 6: Community Driven Development • »Perl 5 was my rewrite of Perl. I want Perl 6 to be the community's rewrite of Perl and of the community.« • Larry Wall 6

  7. Perl 6 Language Specification • http://perlcabal.org/syn/ 7

  8. Perl 6 Language Specification • https://github.com/perl6/specs 8

  9. Perl 6 Language Specification 9

  10. Perl 6 Implementations • »Perl 6 is anything that passes • the official test suite.« • Larry Wall, “Synopsis 1: Overview” 10

  11. Perl 6 Compilers / Interpreters / VMs • Rakudo • Parrot VM backend • JVM backend • Niecza • compiles to CLR (.NET/Mono) • Pugs • one of the first Perl 6 compilers • no longer maintained • STD • Larry Wall’s reference implementation 11

  12. Release Date: Christmas • Rakudo and Niecza are pretty closehttp://perl6.org/compilers/features • Want to play with Perl 6 right now? Use Rakudo *! • Rakudo * = Rakudo Perl 6 compiler, debugger, modules+ Parrot VM • Windows installer, Debian package, cygwin, tarball • PATH=$PATH:…/rakudo/binperl6 helloworld.p6 12

  13. Remove Inconsistencies • »In Perl 6, we decided it would be better to fix the language than fix the user.« • Larry Wall 13

  14. Perl 5 • #!/usr/bin/env perl • use strict; • use warnings; • … 14

  15. Perl 6 • #!/usr/bin/env perl6 • use v6; • # implicit strict & warnings pragmas • # Can be turned off with: • # no strict; • # no warnings; • # but you don’t want to! 15

  16. Sigil Invariance • Perl 5 • my $scalar = "sclr"; • my @array = (1, 2, 3); • my %hash = (foo => 23, bar => 42); 16

  17. Sigil Invariance • Perl 5 • my $scalar = "sclr"; • my @array = (1, 2, 3); • my %hash = (foo => 23, bar => 42); • print $scalar . "\n"; • print @array[0] . "\n"; # works, but warning • print %hash{'foo'} . "\n"; # syntax error 17

  18. Sigil Invariance • Perl 5 • my $scalar = "sclr"; • my @array = (1, 2, 3); • my %hash = (foo => 23, bar => 42); • print $scalar . "\n"; • print $array[1] . "\n"; • print $hash{'bar'} . "\n"; 18

  19. Sigil Invariance • Perl 6 • my $scalar = "sclr"; • my @array = (1, 2, 3); • my %hash = (foo => 23, bar => 42); • print $scalar ~ "\n"; • print @array[0] ~ "\n"; • print %hash{'foo'} ~ "\n"; 19

  20. Sigil Invariance • Perl 6 • my $scalar = "sclr"; • my @array = (1, 2, 3); • my %hash = (foo => 23, bar => 42); • print $scalar ~ "\n"; • print @array[0] ~ "\n"; • print %hash{'foo'} ~ "\n"; • print $array[1]~ "\n"; • # Variable '$array' is not declared. • # Did you mean '@array'? 20

  21. Sigil Invariance • Perl 6 • my $scalar = "sclr"; • my @array = (1, 2, 3); • my %hash = (foo => 23, bar => 42); • print $scalar ~ "\n"; • print @array[0] ~ "\n"; • print %hash{'foo'} ~ "\n"; 21

  22. Sigil Invariance • Perl 6 • my $scalar = "sclr"; • my @array = 1, 2, 3; • my %hash = foo => 23, bar => 42; • say $scalar; • say @array[0]; • say %hash{'foo'}; 22

  23. Sigil Invariance • Perl 6 • my $scalar = "sclr"; • my @array = 1, 2, 3; • my %hash = foo => 23, bar => 42; • say $scalar; • say @array[0]; • say %hash<foo>; 23

  24. Sigil Invariance • # Perl 5: get list from hash of hashes • my @verbs = @{ $dict { 'verb' }{ 'transitive' } }; # Perl 6: get list from hash of hashes my @verbs = %dict{ 'verb' }{ 'transitive' }; # Perl 6: or even like this my @verbs = %dict<verb><transitive>; 24

  25. Perl 6 Basics 25

  26. Subroutines • sub square-and-sum($x, $y) { • return $x*$x + $y*$y; • } • my $a = 3; • my $b = 4; • say "{$a}² + {$b}² = {square-and-sum($a, $b)}"; • # 3² + 4² = 25 26

  27. Subroutines • sub stutter($word) { • my $first-letter = substr($word, 0, 1); • my $wwwword = ($first-letter ~ "-") x 3 ~ $word; • say $wwwword; • } • stutter("what"); # w-w-w-what 27

  28. Subroutines • sub stutterify($word) { • my $first-letter = substr($word, 0, 1); • my $wwwword = ($first-letter ~ "-") x 3 ~ $word; • $word = $wwwword; # no-no! $word is read-only! • } 28

  29. Subroutines • sub stutterify($word is rw) { • my $first-letter = substr($word, 0, 1); • my $wwwword = ($first-letter ~ "-") x 3 ~ $word; • $word = $wwwword; • } 29

  30. Subroutines • sub stutterify($word is rw) { • my $first-letter = substr($word, 0, 1); • my $wwwword = ($first-letter ~ "-") x 3 ~ $word; • $word = $wwwword; • } • my $word = "hello"; • $word.say; # hello • stutterify($word); • $word.say; # h-h-h-hello 30

  31. Subroutines • # pass-by-value • sub say-next-num($num is copy) { • say ++$num; • } • my $num-of-truth = 42; • say-next-num($num-of-truth); • say "The truth is still $num-of-truth"; 31

  32. Dealing with Arrays • sub shout-words(@words) { • for @words -> $word { • say uc($word); • } • } 32

  33. Dealing with Arrays • sub shout-words(@words) { • for @words { • say uc($_); # topic variable • } • } 33

  34. Dealing with Arrays • sub shout-words(@words) { • for @words { say uc($_) } • } • my @words = <hey ho let's go>; • shout-words(@words); • # HEY • # HO • # LET'S • # GO 34

  35. Dealing with Hashes • sub say-names-with-age(%people) { • for %people.kv -> $key, $value { • say $key ~ " (" ~ $value ~ ")"; • } • } 35

  36. Dealing with Hashes • sub say-names-with-age(%people) { • for %people { • say $_.key ~ " (" ~ $_.value ~ ")"; • } • } 36

  37. Dealing with Hashes • sub say-names-with-age(%people) { • for %people { • say .key ~ " (" ~ .value ~ ")"; • } • } 37

  38. Dealing with Hashes • sub say-names-with-age(%people) { • for %people { • say .key ~ " (" ~ .value ~ ")"; • } • } • my %white-family = Walter => 52, Skyler => 41, • "Walter Jr." => 17, Holly => 2; • say-names-with-age(%white-family); 38

  39. Optional Parameters • sub whatever($optional?) { • if defined($optional) { • say "$optional is pretty cool."; • } else { • say "Whatever, man."; • } • } • whatever("The dude"); • whatever(); 39

  40. Named Parameters • sub protip(:$what, :$who) { • say "Use $what, $who!"; • } • protip(:what("the force"), :who("Luke")); • protip(:who("Luke"), :what("the force")); 40

  41. Named Parameters • sub protip(:$what, :$who) { • say "Use $what, $who!"; • } • # short form for strings • protip(:who<Luke>, :what<the force>); 41

  42. Named Parameters • sub protip(:$what, :$who) { • say "Use $what, $who!"; • } • my $thing = "the force"; • my $guy = "Luke"; • #protip( $thing, $guy); # Nope. • #protip(:$thing, :$guy); # Also, nope. • protip(:what($thing), :who($guy)); 42

  43. Named Parameters • sub protip(:$what, :$who) { • say "Use $what, $who!"; • } • my $what = "the force"; • my $who = "Luke"; • protip(:$who, :$what); # names match → magic! 43

  44. Required Named Parameters • sub protip(:$what, :$who) { • say "Use $what, $who!"; • } • # named params are optional by default • protip(); • # use of uninitialized value of type … 44

  45. Required Named Parameters • sub protip(:$what!, :$who!) { • say "Use $what, $who!"; • } • # named params are optional by default • protip(); • # Required named parameter 'what' not passed 45

  46. Varargs with Slurpy Arrays • # varargs with slurpy arrays (* prefix) • sub sum(*@nums) { • [+] @nums; • } • say sum 42, 23, 1337; 46

  47. Varargs with Slurpy Arrays • # default (no "()" given!) is *@_, so: • sub sum { • [+] @_; • } • say sum 42, 23, 1337; 47

  48. Procedural vs. Object Oriented • Perl 6 is object-oriented at its core • You can use it, but you don’t have to (TIMTOWTDI!) 48

  49. Procedural vs. Object Oriented • Perl 6 is object-oriented at its core • You can use it, but you don’t have to (TIMTOWTDI!) • # procedural • say split(" ", capitalize("hello world"))[1]; • # World 49

  50. Procedural vs. Object Oriented • Perl 6 is object-oriented at its core • You can use it, but you don’t have to (TIMTOWTDI!) • # procedural • say split(" ", capitalize("hello world"))[1]; • # World • # object oriented • "hello world".capitalize.split(" ")[1].say; • # World 50

More Related