Jonathan Worthington – Perl 2010 Rit Rakudo

Rakudo Perl 6 What you can do today Jonathan Worthington РИТ++ 2010

Rakudo Perl 6: What You Can Do Today Intro… XXX TODO

Rakudo Perl 6: What You Can Do Today Perl 6

Rakudo Perl 6: What You Can Do Today What is Perl 6? Take the things that make Perl great… Practical - focus on getting the job done Multi-paradigm – because there isn't one approach that's good for all problems Linguistic influences – because it's a programming language Making the easy things easy and the hard things possible

Rakudo Perl 6: What You Can Do Today What is Perl 6? Build a new Perlish language that is… More regular – less special cases More readable and more maintainable More expressive More OO, more functional, more declarative, more parallel… Easy things even easier Harder things even more in reach

Rakudo Perl 6: What You Can Do Today 1 Specification, Many Implementations Unlike Perl 5, Perl 6 has a written language specification No "official" implementation Like Perl 5, Perl 6 has a language test suite A conforming implementation should pass the test suite A kind of "executable specification" Currently around 40,000 tests

Rakudo Perl 6: What You Can Do Today Rakudo

Rakudo Perl 6: What You Can Do Today What is Rakudo? The most actively developed Perl 6 compiler Implements a large portion of the Perl 6 specification (though still some way to go) Today passing over 30,000 tests from the Perl 6 specification test suite (though the suite is still growing ☺) Currently targets the Parrot Virtual Machine Later in the year, we plan to target at least one other platform too

Rakudo Perl 6: What You Can Do Today How Rakudo Works Written in… NQP (Bootstrapped subset of Perl 6) Compiler core (grammar and AST construction), some of the meta-model, module location/loading) Perl 6 The majority of the built-ins and operators Parrot Intermediate Language Some lower-level builtins and "glue" C Dispatchers, signature binder, other VM customizations and glue

Rakudo Perl 6: What You Can Do Today How Rakudo Works: Parsing First, Rakudo parses your program Parser is written in Perl 6 Regexes token statement_control:sym<if> { <sym> :s <xblock> [ 'elsif's <xblock> ]* [ 'else's <else=.pblock> ]? } Some scary stuff… Might discover new operators during parse Have to run BEGIN blocks immediately

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction Whenever we finish parsing something (for example, an if statement), we run an "action method" This builds an Abstract Syntax Tree A representation of the program that is abstracted away from the language syntax Most action methods build up a more complex AST using smaller bits made by things we already parsed

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; }

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; } PAST::Var.new( :name('$x'), :scope('lexical') )

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; } PAST::Var.new( PAST::Val.new( :name('$x'), :value(42) :scope('lexical') ) )

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; } PAST::Op.new( :pasttype('call'), :name('&infix:<==>'), … ) PAST::Var.new( PAST::Val.new( :name('$x'), :value(42) :scope('lexical') ) )

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; } PAST::Op.new( :pasttype('call'), :name('&infix:<==>'), … ) PAST::Var.new( PAST::Val.new( :name('$x'), :value(42) :scope('lexical') ) ) PAST::Val.new( :value('The Answer!') )

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; } PAST::Op.new( :pasttype('call'), :name('&infix:<==>'), … PAST::Op.new( ) :pasttype('call'), :name('&say'), … PAST::Var.new( PAST::Val.new( ) :name('$x'), :value(42) :scope('lexical') ) ) PAST::Val.new( :value('The Answer!') )

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; } PAST::Op.new( PAST::Block.new( … ) :pasttype('call'), :name('&infix:<==>'), … PAST::Op.new( ) :pasttype('call'), :name('&say'), … PAST::Var.new( PAST::Val.new( ) :name('$x'), :value(42) :scope('lexical') ) ) PAST::Val.new( :value('The Answer!') )

Rakudo Perl 6: What You Can Do Today How Rakudo Works: AST Construction if $x == 42 { say "The answer!"; } PAST::Op.new( :pasttype('if'), … ) PAST::Op.new( PAST::Block.new( … ) :pasttype('call'), :name('&infix:<==>'), … PAST::Op.new( ) :pasttype('call'), :name('&say'), … PAST::Var.new( PAST::Val.new( ) :name('$x'), :value(42) :scope('lexical') ) ) PAST::Val.new( :value('The Answer!') )

Rakudo Perl 6: What You Can Do Today How Rakudo Works: Code Generation We take the AST and produce intermediate code for the target platform Today, we can only produce code in this stage for the Parrot VM Architecture means that we'll be able to add more backends in the future Can also insert optimization and program analysis phases at any point in the compilation pipeline

Rakudo Perl 6: What You Can Do Today Examples: What You Can Do Today In Rakudo

Rakudo Perl 6: What You Can Do Today Examples We'll look at a range of small, everyday programming problems and for each one show… The Perl 6 code that solves it The output that code gives when run Hopefully, a good way for you to start to grasp some of the new syntax and features Show of some cool Perl 6 features ☺ All examples shown today work in Rakudo

Rakudo Perl 6: What You Can Do Today Problem Say "Hello, world" Solution say "Hello, world!" Output Hello, world!

Rakudo Perl 6: What You Can Do Today Problem Read input from the console Solution print "Enter your name: "; my $name = $*IN.get; say "Hi $name!"; Output Enter your name: Jonathan Hi Jonathan!

Rakudo Perl 6: What You Can Do Today Problem Check a value is in a given range Solution 1 loop { print "Enter a number from 1 to 10: "; my $num = $*IN.get; unless 1 <= $num <= 10 { say "Fail!" } } Output Enter a number between 1 and 10: 3 Enter a number between 1 and 10: 42 Fail!

Rakudo Perl 6: What You Can Do Today Problem Check a value is in a given range Solution 2 loop { print "Enter a number from 1 to 10: "; my $num = $*IN.get; unless $num ~~ 1..10 { say "Fail!" } } Output Enter a number between 1 and 10: 3 Enter a number between 1 and 10: 42 Fail!

Rakudo Perl 6: What You Can Do Today Problem Add up a list of numbers Solution my @nums = 1, 5, 7, -2, 3, 9, 11, -6, 14; say [+] @nums; Output 42

Rakudo Perl 6: What You Can Do Today Problem Check if a list is sorted Solution my @a = 1, 1, 2, 3, 5, 8; my @b = 9, 4, 1, 16, 36, 25; if [<=] @a { say '@a is sorted' } if [<=] @b { say '@b is sorted' } Output @a is sorted

Rakudo Perl 6: What You Can Do Today Problem Iterate over a list Solution my @cities = <Lisbon Tokyo Seoul Riga>; for @cities -> $city { say "I've been to $city"; } Output I've been to Lisbon I've been to Tokyo I've been to Seoul I've been to Riga

Rakudo Perl 6: What You Can Do Today Problem Iterate over the keys and values of a hash Solution my %distances = Bratislava => 1084, Stockholm => 442; for %distances.kv -> $city, $distance { say "$city is $distance km away"; } Output Bratislava is 1084 km away Stockholm is 442 km away

Rakudo Perl 6: What You Can Do Today Problem Check if any of a list of test scores is a pass Solution my @a = 75, 47, 90, 22, 80; my @b = 61, 77, 94, 82, 60; my @c = 45, 59, 33, 11, 19; if any(@a) >= 60 { say "Some passes in A" } if any(@b) >= 60 { say "Some passes in B" } if any(@c) >= 60 { say "Some passes in C" } Output Some passes in A Some passes in B

Rakudo Perl 6: What You Can Do Today Problem Check if all of a list of test scores are passes Solution my @a = 75, 47, 90, 22, 80; my @b = 61, 77, 94, 82, 60; my @c = 45, 59, 33, 11, 19; if all(@a) >= 60 { say "All passes in A" } if all(@b) >= 60 { say "All passes in B" } if all(@c) >= 60 { say "All passes in C" } Output All passes in B

Rakudo Perl 6: What You Can Do Today Problem Check if none of a list of test scores is a pass Solution my @a = 75, 47, 90, 22, 80; my @b = 61, 77, 94, 82, 60; my @c = 45, 59, 33, 11, 19; if none(@a) >= 60 { say "No passes in A" } if none(@b) >= 60 { say "No passes in B" } if none(@c) >= 60 { say "No passes in C" } Output No passes in C

Rakudo Perl 6: What You Can Do Today Problem Get a random item from a list Solution my @drinks = <wine beer vodka>; say "Tonight I'll drink { @drinks.pick }"; Output (results should vary ;-)) Tonight I'll drink vodka

Rakudo Perl 6: What You Can Do Today Problem Shuffle a list into a random order Solution my @competitors = <Tina Lena Owen Peter>; my @order = @competitors.pick(*); for @order { .say } Output (results should vary ;-)) Peter Lena Owen Tina

Rakudo Perl 6: What You Can Do Today Problem Write and call a subroutine with parameters Solution sub greet($greeting, $name) { say "$greeting, $name!"; } greet("hello", "masak"); Output hello, masak

Rakudo Perl 6: What You Can Do Today Problem Write a subroutine that only takes a number Solution sub double(Num $n) { 2 * $n } say double(21); say double("oh no I'm not a number"); Output 42 Parameter type check failed; expected Num, but got Str for $n in call to double

Rakudo Perl 6: What You Can Do Today Problem Use multi-subs to react differently by type Solution multi double(Num $n) { 2 * $n } multi double(Str $s) { $s x 2 } say double(21); say double("boo"); Output 42 booboo

Rakudo Perl 6: What You Can Do Today Problem Compute factorial (recursively) Solution multi fact($n) { $n * fact($n - 1) } multi fact(0) { 1 } say fact(1); say fact(10); Output 1 3628800

Rakudo Perl 6: What You Can Do Today Problem Compute factorial (using a meta-operator) Solution sub fact($n) { [*] 1..$n } say fact(1); say fact(10); Output 1 3628800

Rakudo Perl 6: What You Can Do Today Problem Add a new factorial operator (so 10! works) Solution sub postfix:<!>($n) { [*] 1..$n } say 1!; say 10!; Output 1 3628800

Rakudo Perl 6: What You Can Do Today Problem Declare a class with attributes and a method Solution class Product { has $.name; # Attr + accessor has $!price; # Attr only has $.discount is rw; # Attr + lvalue accessor method get_price { return $!price - $!discount; } }

Rakudo Perl 6: What You Can Do Today Problem Instantiate a class and call a method on it Solution my $prod = Product.new( name => "Beer", price => 500, discount => 60 ); say $prod.get_price; Output 440

Rakudo Perl 6: What You Can Do Today Problem Get/set attributes through accessors Solution say $prod.name; $prod.discount = 40; say $prod.get_price; $prod.name = 'Wine'; Output Beer 460 Cannot assign to readonly variable.

Rakudo Perl 6: What You Can Do Today Problem Call a method on every object in a list Solution my @products = Product.new(name => 'Beer', price => 500), Product.new(name => 'Wine', price => 450), Product.new(name => 'Vodka', price => 1600); my @uc_names = @products>>.name>>.uc; for @uc_names { .say } Output BEER WINE VODKA

Rakudo Perl 6: What You Can Do Today Problem Introspect a class to find its methods Solution my @meths = Product.^methods(:local); for @meths>>.name { .say } Output get_price discount name

Rakudo Perl 6: What You Can Do Today Problem Sort an array of objects by result of a method Solution (Example 1) my @products = Product.new(name => 'Beer', price => 500), Product.new(name => 'Wine', price => 450), Product.new(name => 'Vodka', price => 1600); my @sorted = @products.sort(*.name); for @sorted { .name.say } Output (Example 1) Beer Vodka Wine

Rakudo Perl 6: What You Can Do Today Problem Sort an array of objects by result of a method Solution (Example 2) my @products = Product.new(name => 'Beer', price => 500), Product.new(name => 'Wine', price => 450), Product.new(name => 'Vodka', price => 1600); my @sorted = @products.sort(*.get_price); for @sorted { .name.say } Output (Example 2) Wine Beer Vodka

Rakudo Perl 6: What You Can Do Today Problem Find minimum and maximum values from a list Solution (Example 1) my @temperatures = -3, 5, 7, 2, -1, -4, 0; say "Minimum was " ~ @temperatures.min; say "Maximum was " ~ @temperatures.max; Output (Example 1) Minimum was –4 Maximum was 7

Rakudo Perl 6: What You Can Do Today Problem Find minimum and maximum values from a list Solution (Example 2) my @products = Product.new(name => 'Beer', price => 500), Product.new(name => 'Wine', price => 450), Product.new(name => 'Vodka', price => 1600); say "Cheapest: " ~ @products.min(*.get_price).name; say "Costliest: " ~ @products.max(*.get_price).name; Output (Example 2) Cheapest: Wine Costliest: Vodka

Rakudo Perl 6: What You Can Do Today Problem Paper, Scissor, Stone game Solution (Part 1) class Paper { } class Scissor { } class Stone { } multi win(Paper, Stone) { "Win" } multi win(Scissor, Paper) { "Win" } multi win(Stone, Scissor) { "Win" } multi win(::T, T) { "Draw" } multi win(Any, Any) { "Lose" }

Rakudo Perl 6: What You Can Do Today Problem Paper, Scissor, Stone game Solution (Part 2) say win(Paper, Paper); say win(Scissor, Stone); say win(Stone, Scissor); Output Draw Lose Win

Rakudo Perl 6: What You Can Do Today Rakudo *

Rakudo Perl 6: What You Can Do Today What is Rakudo *? Rakudo is making great progress Steadily implementing more of the spec Steadily passing more and more tests Fixing lots of bugs Number of active developers is growing So far we have been very much focused on building Rakudo Rakudo * is a release where we instead focus on what early adopters need

Rakudo Perl 6: What You Can Do Today What will the release include? We make a compiler release every month; by contrast, Rakudo * is a distribution release including: The Rakudo compiler, of course ☺ Tool for downloading, installing and updating modules A range of Perl 6 modules that help you achieve some common tasks (e.g. HTTP client/server, database connectivity, web things, YAML…)

Rakudo Perl 6: What You Can Do Today What will the release include? We are also aiming to include a couple of other projects… Zavolaj! – a module that lets you write some basic pure Perl 6 bindings to C libraries; we built a MySQL client with it Blizkost – a Perl 5 Parrot bridge layer that will allow you to use Perl 5 modules from within Perl 6

Rakudo Perl 6: What You Can Do Today What Rakudo * Will Do Well Rakudo has good coverage of a lot of the Perl 6 specification… Wide range of built-in operators, types and functions Subs, signatures and multiple dispatch Object orientation, including classes, roles, introspection and much more Perl 6 regexes and grammars (it's the same engine we use to parse Perl 6!)

Rakudo Perl 6: What You Can Do Today Weaker Areas Rakudo * will have a lot to offer, and should be useful for a range of tasks However, it's not The Full Perl 6, and of course has some weak spots, including: Missing support for threading No native types support Fairly slow – not much work on optimization yet, and no optimizer

Rakudo Perl 6: What You Can Do Today When? Soon ☺

Rakudo Perl 6: What You Can Do Today When? Soon ☺ Either late May or early-mid June

Rakudo Perl 6: What You Can Do Today When? Soon ☺ Either late May or early-mid June Yes, this year

Rakudo Perl 6: What You Can Do Today Get Involved!

Rakudo Perl 6: What You Can Do Today Want to learn more? Get Rakudo Perl 6 from: http://www.rakudo.org/ Lots of Perl 6 resources can be found at: http://www.perl6.org/ Join the friendly IRC channel: #perl6 on irc.freenode.org Write modules, write applications, jump into the evolving Perl 6 community and make your mark on it ☺

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Rakudo Perl 6: What You Can Do Today Questions?

Jonathan Worthington – Perl 2010 Rit Rakudo

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