1. THE JOY OF SIX
Nigel Hamilton + Team
Lean Software Development + Training
Bath, United Kingdom
http://nigelhamilton.com
nige@nigelhamilton.com

2. First a confession ...

3. THE JOY OF SEX

4. OMG – It's THIS Christmas!!!

8. O(fun)

14. Jonathan Worthington
“Perl6: my most
learningist project”
Jnthn++

17. Wetware <=> Hardware

18. O(fun) needs Cognitive Comfort

20. PCRE
^(?:[0-9]{1,3}.){3}[0-9]{1,3}$

21. Fear is a Flow killer
^(?:[0-9]{1,3}.){3}[0-9]{1,3}$

22. Human-friendly Regex Parsing
my $flavour-of-perl = 'Perl 6';
say 'Perl 5 regex matches'
if $flavour-of-perl ~~ m:P5/Perl [56]/;
say 'Perl 6 regex matches'
if $flavour-of-perl ~~ m:i/perl s <[56]>/;
;

23. Regex Revamp
my $ip = '213.120.160.146';
if $ip ~~ m:P5/^(?:[0-9]{1,3}.){3}[0-9]{1,3}$/ {
say 'Perl 5 regex matches';
}
if $ip ~~ /^[<digit> ** 1..3] ** 4 % '.'$/ {
say 'Perl 6 regex matches';
}

24. Ramping Regexen
my token digits {
(<digit>**1..3) <?{ $0 < 256 }>
};
my rule ip-address {
<digits> '.' <digits> '.' <digits>
'.' <digits>

25. Grammar Time!
grammar IP::Address {
token TOP { <v4> }
token v4 {
<digits> '.' <digits> '.' <digits> '.' <digits>
}
token digits {
(d**1..3) <?{ $0 < 256 }>
}
}

26. Comb the Logs
use IP::Address;
my $logs = 'Check these version 4 IPs: 213.120.160.146,
12.10.12.13';
my @ips = $logs.comb(/<IP::Address::v4>/);
IPv6 too?
http://rosettacode.org/wiki/Parse_an_IP_Address#Perl_6

27. Rosetta Stone Code
A+ to ZED
596 Languages
Hundreds of Tasks
Where Larry Wall has
O(fun)
http://rosettacode.org

28. Whipupitude + Expressivity

29. Whipupitude
// Java
public class HelloWorld {
public static void main(String[] args) {
// Prints "Hello, World" to the terminal
System.out.println("Hello, World");
}
}
# Perl 6
say 'Hello, World';
'Hello, World'.say;

30. Whipupitude
#!/usr/bin/env perl6
#| deploy to a node by name
sub MAIN ($node-name) {
say "deploying now to node $node-name";
}
shell> ./deploy.p6 -help
Usage:
./deploy.p6 <node-name> -- deploy to a node by name

31. Whipupitude
use IP::Address;
#| deploy to a node by name
multi sub MAIN ($node-name) {
say "deploying to node: $node-name";
}
#| deploy to a specific IP address
multi sub MAIN ($node-ip where { $_ ~~ /<IP::Address::v4>/ }) {
say "deploying to ip address: $node-ip";
}
shell> ./deploy.p6 -help
Usage:
./deploy.p6 <node-name> -- deploy to a node by name
./deploy.p6 <node-ip> -- deploy to a specific IP address

32. Expressivity
# Perl5 old Skool
sub factorial {
my $n = shift;
my $result = 1;
for (my $i = 1; $i <= $n; ++$i) {
$result *= $i;
};
return $result;
}

33. Iterative / Recursive / Declarative?
Expressive
sub postfix:<!> { [*] 1 .. $^n }
say 5!; # prints 120

34. [Meta] WAT?
- operators on operators

35. [Reduction Meta Operator]
my @numbers = 1 .. 3;
say [+] @numbers;
say [max] @numbers;
say [min] @numbers;
say [~] @numbers;
say [>] @numbers;
say [<] @numbers;
say [>] @numbers.reverse;

36. [Reduction Meta Operator]
my @numbers = 1 .. 3;
say [+] @numbers; # 6
say [max] @numbers; # 3
say [min] @numbers; # 1
say [~] @numbers; # 123
say [>] @numbers; # False
say [<] @numbers; # True
say [>] @numbers.reverse; # True

37. X product – Meta Operator
my @suits = <♣ ♢ ♡ ♠>;
my @ranks = flat 1..10,'J','Q','K','A';
my @deck = @ranks X~ @suits;
my @hand = @deck.pick(5);
say @hand;
shell> perl6 hand.p6
7♣ 5♡ 2♣ J♠ 10♠

38. Lean Coding ...
BOSS: “I need dates for all the last Fridays of the month for
this year”
Lean programmer grabs a highlighter pen and a calendar.
BOSS: “Oh, and for any year out of the last 20”
Lean programmer opens up a terminal window … and types ...

39. Python's Last Friday (14 LOC)
import calendar
c=calendar.Calendar()
fridays={}
year=raw_input("year")
for item in c.yeardatescalendar(int(year)):
for i1 in item:
for i2 in i1:
for i3 in i2:
if "Fri" in i3.ctime() and year in
i3.ctime():
month,day=str(i3).rsplit("-",1)
fridays[month]=day

40. Last Friday in Perl 6 (7 LOC)
sub MAIN (Int :$year = Date.today.year) {
my @fri;
for Date.new("$year-01-01") .. Date.new("$year-12-31"){
@fri[.month] = .Str if .day-of-week == 5;
}
.say for @fri[1..12];
}
shell> perl6 last-friday.p6 --help
Usage:
last-friday.p6 [--year=<Int>]
shell> perl6 last-friday.p6
2015-12-25

41. Whipupitude + Expressivity

43. Discover the Joy of Six

44. The O(fun) must Flow!

45. Go to http://perl6.org and
http://perl6intro.com