2018-05-12 RejectKaigi 2018

10. 2009 21070
2010 22227
2011 21910
2012 22647
2013 25760
2014 27272
2015 22999
2016 19982
2017 16352
2018 6052 => 17096

11. Version.group("TO_CHAR(created_at, 'YYYY')").count.sort
# => [["2009", 39336],
["2010", 59267],
["2011", 82608],
["2012", 104318],
["2013", 125526],
["2014", 155369],
["2015", 132626],
["2016", 121681],
["2017", 108671],
["2018", 36498]] => 105485

30. my $array = ["a", "b", "c"];
for (@$array) {
print $_ . "n";
}
my $array2 = [map { $_ . "foo"; } @$array];

32. def foo
@foo ||= heavy_method
end
# heavy_method boolean
def foo
return @foo if defined?(@foo)
@foo = heavy_method
end

33. sub foo {
shift->{_foo} //= heavy_method
}

34. package Hoge;
use parent 'Exporter';
our @EXPORT = qw/foo bar/;
sub foo { ... }
sub bar { ... }

35. package Fuga;
use Hoge qw/foo/;

36. # perl
reverse uniq grep { $_ ~= /foo/ } <ARGV>;
# ruby
IO.read(ARGF).lines.grep {|l| l ~/foo/ }.uniq.reverse

37. sub hoge {
my $foo = 'foo';
my $bar = 'bar';
{
my $foo = 'baz';
print $foo . $bar . "n"; # => 'bazbar'
}
print $foo . $bar . "n"; # => 'foobar'
}

38. sub hoge {
{
# memcached
my $guard = Proc::Guard->new(command => ["memcached", "-p", "11211"]);
# do something ...
}
# memcached
}

41. our $foo = 'foo';
sub print_foo {
print $foo . "n";
}
print_foo; # foo
{
local $foo = 'bar';
print_foo; # bar
}
print_foo; # foo

44. sub foo {
my ($num, $str) = @_;
print $num . "n";
print $str . "n";
}
foo(1, "a");

45. use Smart::Args::TypeTiny qw(args);
sub create {
args my $id => 'Id',
my $title => 'Str',
my $description => 'Maybe[Str]',
my $comment => { isa => 'Str', optional => 1 },
# do something...
}
# hash
create(
id => 1,
title => "title",
description => undef,
);

47. my $a = localtime;
my @b = localtime;
use Data::Dumper;
print Dumper $a;
# $VAR1 = 'Fri May 4 16:14:45 2018';
print Dumper @b;
# $VAR1 = 45;
# $VAR2 = 14;
# $VAR3 = 16;
# $VAR4 = 4;
# $VAR5 = 4;
# $VAR6 = '118';
# $VAR7 = 5;
# $VAR8 = 123;

51. sub foo { print @_ . 'n'; }
my $method_name = 'foo';
{
#
no strict 'refs';
&{$method_name}('bar');
}

62. 5.027009 => {
delta_from => 5.027008,
changed => {
'B::Op_private' => '5.027009',
... # 140
'warnings' => '1.41',
},
removed => {
'Module::CoreList::TieHashDelta'=> 1,
}
},
5.027010 => {
delta_from => 5.027009,
changed => {
'App::Prove' => '3.42',
... # 193