koorchik's (Viktor Turskyi) presentation from Black Perl 2011 about little-known features in Perl

2. $dbh->do() or die; $sth->execute() or die; #$sth non select statement

3. So, zero can be true

4. “ 0.0” “ 0E0” “ +0” “ 0”

5. “ 0 but true”

6. perl -wE 'say "0 but true"+5' #5 perl -wE 'say "0 but true!"+5' Argument "0 but true!" isn't numeric in addition (+) at -e line 1. #5

7. local

8. our $l = 5; {local $l = 4; say $l}; say $l; #4 #5

9. my $l = 5; {local $l = 4; say $l}; say $l; #Can't localize lexical variable $l at -e line 2.

10. my $l = { a => 5 }; { local $l->{a} = 4; say $l->{a}; }; say $l->{a}; #4 #5

11. my @l = (2,3,5); { local $l[2] = 4; say $l[2]; }; say $l[2]; #4 #5

12. { local $h->{RaiseError}; ... }

13. One line file slurp

14. $content = do {local(@ARGV, $/) = $f; <ARGV>}

15. perl -e 'while (<ARGV>){ … }' f1 f2 f3

16. @INC

17. use everywhere 'MooseX::Declare', matching => '^MyApp', use_here => 0;

18. @INC hooks Subroutine Array Object perldoc -f require

19. $_

20. my @ar = qw/h e l l o/; foreach (@ar) { do_something(); say $_; }

21. Somewhere in outer space... ... Open (my $fh, '<', 'file') while(<$fh>) { ... } ...

22. my @ar = qw/h e l l o/; foreach (@ar) { do_something(); say $_; #undef } say “@ar”; #array of undefs

23. REGEXP in the wake of hackaton

24. say “test1” =~ /t1/; say “test2” =~ //;

25. say “test1” =~ /t1/; # matched say “test2” =~ //; # not matched

26. $text =~ m/ $re /;

27. $text =~ m/ (?:$re) /;

28. ENV PERL5LIB Is there something else?

29. PERL5OPT export PERL5OPT='-MData::Dumper' perl -e 'print Dumper([1,2])'

30. Try::Tiny

31. Why do we need Try::Tiny Clobbering $@ Localizing $@ silently masks errors $@ might not be a true value Shiny syntax perldoc Try::Tiny

32. Fixed in perl 5.14 Clobbering $@ Localizing $@ silently masks errors Remains $@ might not be a true value Shiny syntax

33. Private accessors/methods

34. my $name = sub { my $self = shift; ... } $self->$name(); $self->$name('viktor');

35. use Sub::Name; my $name = subname name => sub { my $self = shift; ... } $self->$name(); $self->$name('viktor');

36. Word that nobody knows how to pronounce me too :)

37. SUITE

38. SUITE [swi:t]

39. Thank you! Viktor Turskyi (koorchik) http://koorchik.blogspot.com