Perl 5.10 for People Who Aren't Totally Insane

Perl 5.10insanefor people who are not

Perl 5.10insanetotallyfor people who are not

perl5100delta

5.10 isn’t like 5.8.x

perl5100delta


- features only get added in new 5.x releases

perl5100delta


- features only get added in new 5.x releases

- it’s been 5 years since the last release (5.8)

perl51000delta

5.10 is Way Cool

perl51000delta

5.10 is Way Cool

- no significant new features in Perl since 2002

perl51000delta

5.10 is Way Cool


- remember how bad you wanted to see Star Wars: Episode 1?

perl51000delta

5.10 is Way Cool



- that’s how excited you should be for 5.10

perl51000delta

5.10 is Way Cool



- that’s how excited you should be for 5.10

- but it won’t suck (no POD race scene)

perl51000delta

Lexicascopasmartwhat?

perl51000delta


- lexically scoped user pragmata!

perl51000delta



- pluggable regex compilation engines!

perl51000delta




- trie-based non-recursive pattern matching!

perl51000delta




- trie-based non-recursive pattern matching!

- thread-safe weak refkey hashes!

perl51000delta

Yes, You Care

perl51000delta

Yes, You Care

- Not everything in 5.10 is esoteric.

perl51000delta

Yes, You Care


- Not everything in 5.10 is for gurus.

perl51000delta

Yes, You Care



- Not everything in 5.10 is for C programmers.

perl51000delta

Yes, You Care



- Not everything in 5.10 is for C programmers.

- Not everything in 5.10 is super advanced.

feature

First: A Warning

feature

First: A Warning

- 5.10 is backwards compatible

feature

First: A Warning


- but adds new keywords and operators

feature

First: A Warning



- they’re not enabled by default

feature

First: A Warning




- use feature ‘mtfnpy’;

feature

First: A Warning





- use 5.010;

feature

First: A Warning





- use 5.010;

- read the perldoc

feature

First: A Warning





- use 5.010;

- read the perldoc I’m a perldoc ref!

feature

First: A Warning





- use 5.010;

- read the perldoc

say what

perlfunc

- new built-in, say

- it’s like print

- but it adds a newline for you

say $what

perlfunc

say $what

perlfunc

say $what

print “Hello, world!\n”;

perlfunc

say $what


print “$message\n”;

perlfunc

say $what



print “$_\n” for @lines;

perlfunc

say $what




say “Hello, world!”;

perlfunc

say $what





say $message;

perlfunc

say $what





say $message;

say for @lines;

truth and definedness

perlop


perlop


sub record_sale {

perlop


sub record_sale { my ($product, $amount) = @_;

perlop



$amount ||= $product->cost;

perlop




...

perlop




...}

perlop

truth and definednesssub record_sale { my ($product, $amount) = @_;

$amount = defined $amount ? $amount : $product->cost;

...}

perlop




...}

perlop




...}

perlop

the new OR operator


$amount //= $product->cost;

...}

perlop

the new OR operator

$setting = defined $given ? $given : $default;

perlop

the new OR operator

$setting = $given;unless (defined $setting) { $setting = $default;}

perlop

the new OR operator

$setting = $given || $default;

perlop

the new OR operator

$setting = $given // $default;

keeping state

perlsub

$lines_left = 100;

sub read_line { die “trial period expired” unless $lines_left-- > 0; ...}

State Variables

perlsub

my $lines_left = 100;

sub read_line { die “trial period expired” unless $lines_left-- > 0; ...}

State Variables

perlsub

{ my $lines_left = 100;

sub read_line { die “trial period expired” unless $lines_left-- > 0; ... }}

State Variables

perlsub

package Trial::Period;sub new { my ($class, $arg) = @_; my $guts = { lines_left => $arg->{lines}, error_msg => $arg->{error}, }; return bless $guts => $class;}

sub consume_line { my ($self) = @_; $self->{lines_left}--;}

sub lines_left { my ($self) = @_; return $self->{lines_left};}

sub assert_lines_left { my ($self) = @_; unless ($self->lines_left) { die $self->{error_msg}; }}1;

State Variables

my $LINES = 100;my $ERROR = “sorry, trial period over”;my $TRIAL = Trial::Period->new({ lines => $LINES, error => $ERROR,});

sub read_line { $TRIAL->assert_lines_left; ...}

perlsub

{ my $lines_left = 100;

sub read_line { die “trial period expired” unless $lines_left-- > 0; ... }}

State Variables

perlsub

sub read_line { state $lines_left = 100; die “trial period expired” unless $lines_left-- > 0; ...}

State Variables

-x stacking

perlfunc

if ( -f $fileand -w $fileand -z $file

) {unlink $file;

}

Stackable File Tests

perlfunc

if ( -f $file and -w _ and -z _) {unlink $file;

}


perlfunc

if (-f -w -z $file) {unlink $file;

}


smart matching

perlsyn

Smart Matching

perlsyn

Smart Matching

- a new kind of comparison operator

perlsyn

Smart Matching


- its behavior depends on its inputs

perlsyn

Smart Matching



- “if these two things match...”

perlsyn

Smart Matching



- “if these two things match...”

- hard to tell, easy to show...

perlsyn

Smart Matching

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ @array) { ... }

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ @array) { ... }elsif ($foo ~~ $code) { ... }

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ @array) { ... }elsif ($foo ~~ $code) { ... }elsif ($foo ~~ %hash) { ... }

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ @array) { ... }elsif ($foo ~~ $code) { ... }elsif ($foo ~~ %hash) { ... }elsif ($foo ~~ qr/re/) { ... }

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ @array) { ... }elsif ($foo ~~ $code) { ... }elsif ($foo ~~ %hash) { ... }elsif ($foo ~~ qr/re/) { ... }elsif ($foo ~~ $bar) { ... }

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ @array) { ... }elsif ($foo ~~ $code) { ... }elsif ($foo ~~ %hash) { ... }elsif ($foo ~~ qr/re/) { ... }elsif ($foo ~~ $bar) { ... }else { ... }

perlsyn

Smart Matchinggiven ($foo) { when (undef) { ... } when (@array) { ... } when ($code) { ... } when (%hash) { ... } when (qr/re/) { ... } when ($bar) { ... } default { ... }}

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ @array) { ... }elsif ($foo ~~ $code) { ... }elsif ($foo ~~ %hash) { ... }elsif ($foo ~~ qr/re/) { ... }elsif ($foo ~~ $bar) { ... }else { ... }

perlsyn

Smart Matching

if ($foo ~~ undef) { ... }elsif ($foo ~~ $array) { ... }elsif ($foo ~~ $code) { ... }elsif ($foo ~~ $hash) { ... }elsif ($foo ~~ qr/re/) { ... }elsif ($foo ~~ $bar) { ... }else { ... }

perlsyn

Smart Matching

my $test;

perlsyn

Smart Matchinggiven ($foo) { when (undef) { ... } when ($aref) { ... } when ($code) { ... } when ($href) { ... } when ($regex) { ... } when ($object) { ... } default { ... }}

perlsyn

Smart Matchinggiven ($foo) { when ($test_1) { ... } when ($test_2) { ... } when ($test_3) { ... } when ($test_4) { ... } when ($test_5) { ... } when ($test_6) { ... } default { ... }}

perlsyn

Smart Matching

perlsyn

Smart Matching

@want = @have->where($test)

perlsyn

Smart Matching


@want = @have->where(sub{ …… })

perlsyn

Smart Matching



@want = @have->where(qr/.../sm)

perlsyn

Smart Matching



@want = @have->where(qr/.../sm)

@want = @have->where([ 1,2,3 ])

perlsyn

Smart Matching

perlsyn

Smart Matchingsub where {

perlsyn

Smart Matchingsub where { my ($array, $test) = @_;

perlsyn


if (ref $test eq ‘ARRAY’) {

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test;

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array;

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array; }

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array; } if (ref $test eq ‘Regexp’) {

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array; } if (ref $test eq ‘Regexp’) { return grep { $_ =~ $test } @$array;

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array; } if (ref $test eq ‘Regexp’) { return grep { $_ =~ $test } @$array; }

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array; } if (ref $test eq ‘Regexp’) { return grep { $_ =~ $test } @$array; } if (ref $test eq ‘CODE’) {

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array; } if (ref $test eq ‘Regexp’) { return grep { $_ =~ $test } @$array; } if (ref $test eq ‘CODE’) { return grep { $test->($_) } @$array;

perlsyn


if (ref $test eq ‘ARRAY’) { my %known = map {$_=>1} @$test; return grep { $known{$_} } @$array; } if (ref $test eq ‘Regexp’) { return grep { $_ =~ $test } @$array; } if (ref $test eq ‘CODE’) { return grep { $test->($_) } @$array; }

perlsyn



die “invalid test”

perlsyn



die “invalid test”}

perlsyn

Smart Matching

sub where { my ($array, $test) = @_; grep { $_ ~~ $test } @$array;}

perlsyn

Smart Matching

SmartMatch::Sugar

perlsyn

Smart Matching

@want = @have->where( hash )

SmartMatch::Sugar

perlsyn

Smart Matching


@want = @have->where( class )

SmartMatch::Sugar

perlsyn

Smart Matching


@want = @have->where( class )

@want = @have->where(isa(‘Foo’))

SmartMatch::Sugar

unknown undefined

perldiag

$str = “Greetings, $name. Your last login was $last. It is now $time.”;

Better Error Message(s)

perldiag



Use of uninitialized value in concatenation (.) or string at hello.plx line 9.

perldiag


Use of uninitialized value $time in concatenation (.) or string at hello.plx line 9.


inside-out objects

Hash::Util::FieldHash

Inside-Out Objects


Inside-Out Objects

- traditional objects are a hashref


Inside-Out Objects


- look up attrs in the obj itself by attr name


Inside-Out Objects



- inside-out objects are content-free refs


Inside-Out Objects




- look up attrs in an external hash by obj id


Inside-Out Objects




- look up attrs in an external hash by obj id

- there are complications for inside-out objects


Inside-Out Objects

sub size { my $self = shift;

if (@_) { return $self->{size} = shift; } else { return $self->{size}; }}


Inside-Out Objectsmy %size;sub size { my $self = shift;

if (@_) { return $size{ $self } = shift; } else { return $size{ $self }; }}


Inside-Out Objectsmy %size;sub size { my $self = shift; my $id = refaddr $self;

if (@_) { return $size{ $id } = shift; } else { return $size{ $id }; }}




sub DESTROY { my $id = refaddr $_[0]; delete $size{ $id };}




sub DESTROY { my $id = refaddr $_[0]; delete $size{ $id };}

sub CLONE { my $class = shift;

my @properties = map { values %$_ } values %PROP_DATA_FOR;

for my $old_id ( keys %OBJ ) {

my $object = $OBJ{ $old_id }; my $new_id = refaddr $object;

for my $prop ( @properties ) { next unless exists $prop->{ $old }; $prop->{ $new } = $prop->{ $old }; delete $prop->{ $old }; }

weaken ( $OBJ{ $new } = $object ); delete $OBJ{ $old }; }}


Inside-Out Objectsmy %OBJECT_REGISTRY;my %size;sub size { my $self = shift; my $id = refaddr $self;

$self->register_object;


sub DESTROY { my $id = refaddr $_[0]; delete $size{ $id }; delete $OBJECT_REGISTRY{ $id };}

sub register_object { my ($self) = @_; my $id = refaddr $self; $OBJECT_REGISTRY{ $id } = $self;}

sub CLONE { my $class = shift;

my @properties = map { values %$_ } values %PROP_DATA_FOR;

for my $old_id ( keys %OBJECT_REGISTRY ) {

my $object = $OBJECT_REGISTRY{ $old_id }; my $new_id = refaddr $object;

for my $prop ( @properties ) { next unless exists $prop->{ $old_id }; $prop->{ $new_id } = $prop->{ $old_id }; delete $prop->{ $old_id }; }

weaken ( $OBJECT_REGISTRY{ $new_id } = $object ); delete $OBJECT_REGISTRY{ $old_id }; }}


Field Hashes


Field Hashes

- they’re just like hashes


Field Hashes


- objects as keys become object ids


Field Hashes


- objects as keys become object ids

- but get destroyed and cloned


Field Hashesmy %size;sub size { my $self = shift;



Field Hashesfieldhash my %size;sub size { my $self = shift;



Field Hashes{ fieldhash my %size; sub size { my $self = shift; if (@_) { return $size{ $self } = shift; } else { return $size{ $self }; } }}


Field Hashessub size { my $self = shift; fieldhash state %size;


lexical topic

(topic is how you say $_)

perlvar

for (@lines) { chomp; next if /^#/; next unless length; s/a/b/; sanity_check; say;}

Lexical Topic

perlvar

Lexical Topic

for my $line (@lines) { chomp $line; next if $line ~~ /^#/; next unless length $line; $line =~ s/a/b/; sanity_check($line); say $line;}

perlvar

for my $_ (@lines) { chomp; next if /^#/; next unless length; s/a/b/; sanity_check; say;}

Lexical Topic

Regex

named captures

perlre

Regex: Named Captures

perlre


- find matches by name, not position

perlre



- avoid the dreaded $1

perlre



- avoid the dreaded $1

- no longer second to Python or .Net!

perlre

# our hypothetical format

section:property = value


perlre

$line ~~ /(\w+):(\w+) = (\w+)/;

$name = $2;$value = $3;


perlre

$lhs_re = qr/(\w+):(\w+)/;$rhs_re = qr/(\w+)/;

$line ~~ /$lhs_re = $rhs_re/;

$name = $2;$value = $3;


perlre


$name = $2;$value = $3;


perlre


$name = $+{ name }; $value = $+{ value };


perlre

$lhs_re = qr/(\w+):(\w+)/;$rhs_re = qr/(\w+)/;


perlre

$lhs_re = qr/(\w+):(?<name>\w+)/;$rhs_re = qr/(?<value>\w+)/;


better backrefs

perlre

Regex: Backreference

m{< (\w+) > .+ < /\1 > }x

perlre


m{< (\w+) > .+ < /\1 > }x

perlre


\10

perlre


qr{(\d)\10}

perlre


qr{ (\d) \1 0}x

perlre


m{< (\w+) > .+ < /\1 > }x

perlre


m{< (\w+) > .+ < /\g{1} > }x

perlre


\10

perlre


\g{10}

perlre


qr{(\d)\10}

perlre


qr{(\d)\g{1}0}

perlre


qr{(\d)\g{-1}0}

perlre


qr{ (?<digit>\d) \g{digit} 0}x

wtf

Regex: Exit Strategymy $wtf_re = qr{xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:(?:[^(\040)<>@,;:”.\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:”.\\\[\]\000-\037\x80-\xff])|”[^\\\x80-\xff\n\015“]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015”]*)*”)[\040\t]*(?:$[^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*$)[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:\.[\040\t]*(?:$[^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*$)[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:”.\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:”.\\\[\]\000-\037\x80-\xff])|”[^\\\x80-\xff\n\015”]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015”]*)*”)[\040\t]*(?:$[^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*$)[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*)*@[\040\t]*(?:$[^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*$)[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:”.\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:”.\\\[\]\000-\037\x80-\xff])|\[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\040\t]*(?:$[^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*$)[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:\.[\04};

perlop


if ($str =~ $wtf_re) { ...}

perlop


if ($str ~~ $wtf_re) { ...}

lexically scoped alternate trie-based reentrant user-defined regex pragmata

flexible regex

perlreapi

Alternate Regex Engines

perlreapi


- lets you change how regex work

perlreapi


- lets you change how regex work

- but not how you use them (=~, s///, etc)

re::engine::POSIX


re::engine::POSIX


egrep -r -l PATTERN DIR

re::engine::POSIX


my $regex = qr{ ... };

my @files = $find->file->in( $root );

say for grep { slurp ~~ $re } @files;

re::engine::POSIX


re::engine::POSIX


egrep -r -l ‘.+?’ DIR

re::engine::POSIX





re::engine::POSIX


use re::engine::POSIX;




re::engine::POSIX


use re::engine::POSIX;

my $regex = qr{ ... }x;



http://www.perl.org/get.html

Any questions?

Date post:	11-Jun-2015
Category:	Business
Upload:	ricardo-signes
View:	84,309 times
Download:	1 times

Perl 5.10 for People Who Aren't Totally Insane

Business