perldelta redux.md

Perl Delta Redux.

5.18

• warnings category for experimental features
• Hashes now randomized
• New Hash functions
• PERL_HASH_SEED = hex string
• PERL_PERTURB_KEYS
• Hash::Util::hash_seed() returns a string
• PERL_HASH_SEED_DEBUG more detailed
• Unicode 6.2
• Support for non-latin-1 character name custom aliases
• ${^LAST_FH}
• Character class set operations in regexps, ie:

$char =~ /(?[ \p{Cyrillic} & \p{Lower} ])/

• lexical subs

my sub foo {  };
foo();

• computed labels

my $GOTO_TABLE = {
    0 => 'A',
    1 => 'B',
    2 => 'B',
    3 => 'A',
    4 => 'A',
    5 => 'A',
    6 => 'B',
};

C: {
    A: for my $a ( 0 .. 8 ) {
      B:  for my $b ( 0 .. 3 ) {
        print "$a . $b\n";
        next $GOTO_TABLE->{$a} || 'C';
      }
    }
}

→

0 . 0
1 . 0
1 . 1
1 . 2
1 . 3
2 . 0
2 . 1
2 . 2
2 . 3
3 . 0
4 . 0
5 . 0
6 . 0
6 . 1
6 . 2
6 . 3
7 . 0

• Bunch of stuff added to CORE:: : defined, delete, exists, glob, pos, protoytpe, scalar, split, study, undef
• kill -INT $ID sends SIGINT to process group $ID instead of sending 0 ( Previously you needed to say -15 )
• Unknown names in \N{...} a syntax error
• Invalid character name aliases in \N{...} a syntax error.
• \N{BELL} is 🔔( U+1F514) instead of � (U + 0007 ). Use \N{ALERT} if you want the control charachter.
• New Restrictions in Multi-Character Case-Insensitive Matching in Regular Expression Bracketed Character Classes -- somebody explain this in a way a human can understand, I read it and its nonsense to me.
• single character variables ( ie: $v ) now imply the same restrictions as normal variables
• ${foo:bar} and $foo:bar are now equally invalid
• vertical tabs (\cK ) are now whitespace (\s) everywhere.
• s///e stricter. My god. This was valid code:

%_=(_,"Just another ");
$_="Perl hacker,\n";
s//_}->{_/e;print

• given aliases $_ like foreach () {}
• smartmatch ( ~~ ) deemed experimental
• lexical $_ now experiemental, documentation here is hard to grok
• $/ = \8; my $scalar = <> reads 8 characters, not 8 bytes.
• <<"Foo"; parsing always occurs on line after the heredoc ( perl #114040 )
• m/foo/and 1 no longer valid, → m/foo/ and 1
• for qw( 1 2 3 ) {} no longer valid → for (qw( 1 2 3 ) ){ }
• use warnings no longer accidentally turns off warnings that are already turned on
• state sub { } and our sub { } now only valid under lexical_subs
• Assigning to %ENV now stringifies and downgrades to bytes within the perl interpreter, not only in children inheriting %ENV
• require now considers a present, but unreadable file an error and dies instead of ignoring the file and continuing searching @INC
• split ' ', $bar now behaves the same as $foo = ' '; split $foo, $bar
• shit with m{fooo\{1,3\}} meaning the slashes escape the outerbrackets, not the metacharacter behaviour
• /( ?foo )/ and /( *foo )/ deprecated, use /(?foo)/ and /(?*foo)/ plzkthx

5.16

5.14

5.12

5.10

5.8