Antiquated Perl

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Antiquated Perl

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Modern Perl?

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Post Modern Perl

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Enlightened Perl

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everybody knows

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Catalyst
Moose
DBIx::Class

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Modern Perl?

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perl5 v10

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  given ($x) {
   when (3) {
  ...

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~~

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what's the opposite?

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Old Perl?

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if it works

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Legacy Perl?

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not interesting

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Stupid Perl

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*$&^*(^ FormMail.PL

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Antiquated Perl

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Antique

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Old *and* beautiful

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Simple Elegant

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  $|++

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  use IO::Handle;
  STDOUT->autoflush(1);

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it's core.
it's fine.

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but why think?

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  select((select(FOO),$|++)[0])

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  (select(FOO),$|++)
  ->
  ($old_selected_fh,$|)

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  (select(FOO),$|++)[0]
  ->
  $old_select_fh

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  select((select(FOO),$|++)[0])
  ->
  use IO::Handle;
  FOO->autoflush(1)

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~~

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  ~~@x

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  ~(~(@x))

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bitwise negation

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so ...

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  ~@x
  ->
  ~(scalar @x)

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  ~~$number
  ->
  $number

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  ~~@x
  ->
  scalar @x

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  perl -MMoose -e'print ~~keys %INC'
  84

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overload::constant

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lets you affect parsing

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numbers strings

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q qq qr t s qw

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i18n.pm

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~~"$foo bar"
loc("_[0] bar", $foo)

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for

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  for ($foo) {
    /bar/ and ...

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  for ($foo) {
    /bar/ and return do {
      <code here>
    }

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  /foo/gc

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  /\Gbar/gc

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  sub parse {
    my ($self, $str) = @_;
    for ($str) {
      /match1/gc and return
        $self->_subparse_1($_)

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  sub _subparse_1 {
    my ($self) = @_;
    for ($_[1]) {
      /\Gsubmatch1/gc ...

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prototypes

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  sub foo (&) {

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  foo {
    ...
  };

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  prototype \&foo

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typeglobs

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  *{"${package}::${name}"}
    = sub { ... }

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  local

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  local $_

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  local *Carp::croak
    = \&Carp::confess;

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  do {
    local (@ARGV, $/) = $file;
    <>
  }

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strict and warnings

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  strict->import

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affects compilation scope

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  sub strict_and_warnings::import {
    strict->import;
    warnings->import;
  }

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  use strict_and_warnings;

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$^H
%^H

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  $^H |= 0x120000;
  $^H{'foo'}
    = bless($foo, 'My::Foo');

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  sub My::Foo::DESTROY {

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  delete ${$package}{myimport}

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B::Hooks::EndOfScope

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tie

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  tie $var, 'Foo';

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  sub FETCH
  sub STORE

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Scalar 
Array 
Hash
Handle

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now ...

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mst: destruction testing technology since March 1983

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3 days old

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2 weeks early

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incubator

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glass box 
plastic tray
heater

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design flaw

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BANG

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so ...

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interesting fact

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prototypes only warn
when parsed

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error when compiled

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so ...

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  dispatch [
    sub (GET + /) { ... },
    sub (GET + /user/*) { ... }
  ];

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  foreach my $sub (@$dispatch) {
    my $proto = prototype $sub;
    $parser->parse($proto);
    ...

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  PARSE: { do {
    push @match, $self->_parse_spec_section($spec)
      or $self->_blam("Unable to work out what the next section is");
    last PARSE if (pos == length);
    /\G\+/gc or $self->_blam('Spec sections must be separated by +');
  } until (pos == length) };

----

  sub _blam {
    my ($self, $error) = @_;
    my $hat = (' ' x pos).'^';
    die "Error parsing dispatch specification: ${error}\n
  ${_}
  ${hat} here\n";
  }

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  Error parsing ...
  GET+/foo
     ^ here

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  sub (GET + /user/*) {
   my ($self, $user) = @_;

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I hate fetching
 $self

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  *{"${app}::self"}
    = \${"${app}::self"};

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use vars

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  sub _run_with_self {
    my ($self, $run, @args) = @_;
    my $class = ref($self);
    no strict 'refs';
    local *{"${class}::self"} = \$self;
    $self->$run(@args);
  }

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HTML output

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templates

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HTML is NOT TEXT

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  <div>,
    $text,
  </div>;

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<div>

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<$fh>

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  tie *{"${app}::${name}"},
    'XML::Tags::TIEHANDLE',
    "<${name}>";

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  sub TIEHANDLE { my $str = $_[1]; bless \$str, $_[0] }
  sub READLINE { ${$_[0]} }

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  sub DESTROY {
    my ($into, @names) = @$_[0];
    no strict 'refs';
    delete ${$into}{$_}
      for @names;
  }

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</div>

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glob('/div');

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  *CORE::GLOBAL::glob
    = sub { ... };

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  delete
    ${CORE::GLOBAL::}{glob};

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  sub foo {
    use XML::Tags qw(div);
    <div>, "foo!", </div>;
  }

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what about interpolation

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  my $stuff = 'foo"bar';
  <a href="$stuff">

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hmm ...

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overload::constant!

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  glob('a href="'.$stuff.'"');

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  glob(
    bless(\'a href="', 'MagicTag')
    .$stuff
    .bless(\'"', 'MagicTag')
  )

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  use overload
    '.' => 'concat';

   sub concat {

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hooking it up

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  sub (.html) {
    filter_response {
      $self->render_html($_[1])
    }
  }

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  bless(
    $_[1],
    'Web::Simple::ResponseFilter'
  );

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  if ($self->_is_response_filter($result)) {
    return $self->_run_with_self(
      $result,
      $self->_run_dispatch_for($new_env, \@disp)
    );
  }

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and the result?

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 goto &demo;

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questions?

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thank you

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