Some tools to use in actual projects

1. Modern Perl

2. use v5.10;

5. say my_sub_call(...);

7. or $name // = 'oleber';

11. or if ( @array ~~ /pippo/ ) { … }

13. or sub xpto { state $static_var = 0; ... }

15. "K" escape, floating length positive lookbehind: s/(foo)bar/$1/g becomes s/fooKbar//g

16. Backtracking control verbs

17. ...

18. Object Oriented

19. use Moose; package Person; use Moose; # now it's a Moose class! # imports strict and warnings ... no Moose ; __PACKAGE__->meta->make_immutable ;

20. Moose attributes has id => ( is => 'ro' , isa => 'Int' , ); has name => ( is => 'rw' , isa => 'Str' , ); my $person = new Person(id => 123, name => ' John '); $person->name('peter'); # OK $person->id(12); # NOK

22. HashRef[CodeRef] # a hash of str to Code ref

23. ...

24. Define your types use Moose::Util::TypeConstraints; subtype 'Telephone' => as 'Str' => where { $_ =~ /^d+$/}; no Moose::Util::TypeConstraints; has telephone => ( is => 'rw', isa => 'Telephone' , ); $person->telephone('35196219374'); # OK $person->telephone('XPTO'); # NOK

25. Moose class Inheritance package User; use Moose; extends 'Person'; has login => ( is => 'rw', isa => 'Str', ); ... my $user = new User(id => 52, login => 'oleber')

26. Moose Method sub do_login { my ($self, $password) = @_; ... }

27. Moose method modifiers before do_login => sub { my ( $self, $pass ) = @_; warn "Called login() with $pass
"; }; around name => sub { my ($orig, $self, @args) = @_; return ucfirst lc $self->$orig( @args ) ; }; ...

30. The old DESTROY is used internally by Moose

31. You shall use the DEMOLISH() method

32. Call methods on native types

33. autobox use JSON; say to_json [ map { $_ ** 2 } @array ]; use autobox; local *ARRAY::map = sub { my ( $self, $block ) = @_; return [map {&$block($_)} @$self ]; }; local *ARRAY::to_json = sub { return to_json(shift); }; say @array->map( sub { $_ ** 2 } )->to_json;

35. [1..10]->foreach(sub { ... }) resolves to: ARRAY::foreach([1..10], sub { ... })

38. Moose::Autobox

39. Exception handling

40. Error use Error qw(:try); try { throw ...; } catch Error::IO with { my $E = shift; warn "File $E->{'-file'} had a problem
"; } except { my $E = shift; warn "ERROR: " . Dumper $E; } otherwise { say "ALL OK
"; } finally { say "Finished" } ; # Don't forget the trailing ;

41. TryCatch use TryCatch; try { die ... } catch ( PKG_1 $e where { $_->code > 100 } ) { ... } catch ( PKG_2 $e ) { ... } catch ( $e ) { ... } catch { ... }

42. It is better to die() than to return() in failure. (Paul Fenwick) The Box Jellyfish Saltwater Crocodile Blue Ring Octopus Stone fish Red Back Spider Funnel Web Spider

43. autodie open(my $FH, ">>", $path) or die "Can't open $!"; system($cmd) == 0 or die "system failed: $?"; if ( defined ( my $pid = fork() ) ) { if ( $pid != 0 ) { # parent } else { # child } } else { die "Can't fork"; }

44. autodie use autodie qw(:all); open(my $FH, ">>", $path) or die "Can't open $!"; system($cmd) == 0 or die "system failed: $?"; if ( defined ( my $pid = fork() ) ) { if ( $pid != 0 ) { # parent } else { # child } } else { die "Can't fork"; }

45. autodie use autodie qw(:all); open(my $FH, ">>", $path); system($cmd) == 0 or die "system failed: $?"; if ( defined ( my $pid = fork() ) ) { if ( $pid != 0 ) { # parent } else { # child } } else { die "Can't fork"; }

46. autodie use autodie qw(:all); open(my $FH, ">>", $path); system($cmd); if ( defined ( my $pid = fork() ) ) { if ( $pid != 0 ) { # parent } else { # child } } else { die "Can't fork"; }

47. autodie use autodie qw(:all); open(my $FH, ">>", $path); system($cmd); if ( ( my $pid = fork() ) != 0 ) { # parent } else { # child }

48. autodie error analyse eval { use autodie; open(my $FH, '<', $some_file); while ( my $line = readline $FH ) { ... } close($fh); }; given ($@) { when (undef) { say &quot;No error&quot;; } when ('open') { say &quot;Error from open&quot;; } when (':io') { say &quot;Non-open, IO error.&quot;; } when (':all') { say &quot;autodie error.&quot; } default { say &quot;Not an autodie error.&quot; } }

51. Crazy Errors

52. Good Coding Style

53. Perl Best Practices

55. Efficiency: faster code.

57. perldoc perlstyle

61. hard to read code

62. error-prone code

64. Unit test

65. Test::Simple use Test::Simple tests => 2; ok ( 1 + 1 == 2, &quot;sum&quot; ); ok ( 2 * 3 == 5, &quot;multiplication&quot;); prints: 1..2 ok 1 - sum not ok 2 - multiplication # Failed test 'multiplication' # at script.t line 6. # Looks like you failed 1 test of 2.

66. Test::More Complex stuff use Test::More 'no_plan'; ok ( 1 + 1 == 2, &quot;sum&quot; ); is ( 1 + 1, 2, 'add'); isnt ( 2 * 3, 5, 'multiplication'); is_deeply ({1..4}, {1=>2, 3=>4}, &quot;similar hash&quot;); my $str = 'Hello, World!'; like ($str, qr/Hello/, 'match'); unlike ($str, qr/Dude/, 'No way Dude'); use_ok ('Person'); can_ok ('Person', 'name'); ...

68. Test::Output - Test STDOUT and STDERR messages.

69. Test::DatabaseRow - Simple database tests

70. Test::WWW::Mechanize - Test web application

71. Apache::Test - Test Apache

72. ...

73. ? Question & Answers