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<h1>Reini Urban • Riga Tue Aug 16, 2011</h1>
<h2>use types YAPC::EU 2011</h2></div>
</div><div class="slide">
<h1>use types;
</h1><p>YAPC::EU 2011
</p><p><b>rurban</b> - Reini Urban <br>
<code>vienna.pm</code> => <code>houston.pm</code>
</p></div>
<div class="slide">
<h1>Goal
</h1><p><br><br>
</p><p>Provide type semantics to enable more compile-time
optimizations, to make Perl and compiled Perl smaller and faster.
</p></div>
<div class="slide">
<h1>Outline
</h1><ul><li level="1">Status Quo: CORE types
<p><code>my TYPE $i; my My::Class $o;</code> # Declaration only <br>
package TYPE must exist
</p></li><li level="1">Optimizations planned for 5.16 - 5.18
<p>smaller and faster, ensured at compile-time:<br>
faster method calls, fix types, declarations via class and attributes,
typed arrays + hashes, perfect hashes.
</p></li><li level="1">Artur Bergman's <b>types</b> module
<p>Declare and check type safety. int, double, number, string.
params and return values.
</p></li></ul></div>
<div class="slide">
<h1>About me
</h1><p><img src=pix/austria-shitty-little-country.jpg>
</p></div>
<div class="slide">
<h1>About me
</h1><p>Architect. Mainly LISP for several years. Perl as better build system.
</p><p><b>rurban</b> maintains <b>cygwin perl</b> since 5.8.8
and some modules: illguts, <b>B::*</b> => 5.10,
mainly the "compiler".
</p><p>No perl dayjob, just for fun. Until now.
</p><p>In the future a <b>lot</b> more time for the compiler and CORE.
Left <b>AVL</b> (<i>automotive industry</i>), went to <b>cPanel</b> to
improve the compiler.
</p></div>
<div class="slide">
<h1>Perl's Type System
</h1><b>my</b> <font color="#007f00">int</font> <font color="#0000ff">$var</font>; <font color="#7f7f7f"><i># or our</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<font color="#7f7f7f"><i># my :attribs are not known at compile-time, only our.</i></font><font color="#7f7f7f"><i><BR>
</i></font>$ perl <font color="#ffa500">-c</font>w <font color="#ffa500">-e</font> <font color="#ffa500">'</font><font color="#ff0000">package int; package main; our int $i:const;</font><font color="#ffa500">'</font><BR>
Invalid <font color="#007f00">SCALAR</font> attribute: const at <font color="#ffa500">-e</font> line <font color="#00007f">1</font><BR>
$ perl <font color="#ffa500">-c</font>w <font color="#ffa500">-e</font> <font color="#ffa500">'</font><font color="#ff0000">package int; package main; my int $i:const;</font><font color="#ffa500">'</font><BR>
<font color="#ffa500">-e</font> syntax OK<BR>
<BR>
<p>FETCH_SCALAR_ATTRIBUTES => New <b>CHECK_SCALAR_ATTRIBUTES</b> callback for <code>my</code>.
</p></div>
<div class="slide">
<h1>Perl's Type System
</h1><p>Yes, the language already has one. CORE:
</p> <b>my</b> TYPE <font color="#0000ff">$var</font>;<BR>
<b>sub </b><font color="#007f00">name</font> (proto) {} => proto: &name->pv<BR>
<BR>
<p>Only a few out-of-CORE implementations: <br>
</p><p>Moose, fields, <strike>types, typesafety</strike>, Lexical::Types,
Attribute::Types <i>(run-time)</i>
</p><p><b>Params</b>: <code>Devel::Declare</code>, <code>Params::Validate</code>, <code>Params::Classify</code> <br>
<b>Objects</b>: <code>Class::Meta</code>, <code>Moose</code>
</p></div>
<div class="slide">
<h1>Prototypes
</h1><p>No standard prototype language, no CPAN prototype parser!
</p><font color="#7f7f7f"><i># types 0.x</i></font><font color="#7f7f7f"><i><BR>
</i></font><b>sub </b><font color="#007f00">foo</font> (<font color="#007f00">int</font> <font color="#0000ff">$foo</font>) { <b>my</b> (<font color="#0000ff">$foo</font>) = <font color="#0000ff">@_</font> } <font color="#7f7f7f"><i># return type implicit. </i></font><font color="#7f7f7f"><i><BR>
</i></font><font color="#7f7f7f"><i>#No optree injection as in Devel::Declare</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<font color="#7f7f7f"><i># typesafety</i></font><font color="#7f7f7f"><i><BR>
</i></font><b>sub </b><font color="#007f00">foo</font> (<font color="#007f00">int</font>; <font color="#007f00">int</font>, <font color="#007f00">undef</font>) <font color="#7f7f7f"><i># returns int</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<font color="#7f7f7f"><i># types 1.0</i></font><font color="#7f7f7f"><i><BR>
</i></font><b>sub </b><font color="#007f00">foo</font> (<font color="#007f00">int</font> <font color="#0000ff">$i</font> => <font color="#007f00">int</font>) { <b>return</b> <font color="#00007f">2</font> <font color="#ffa500">*</font> <font color="#0000ff">$i</font> } <font color="#7f7f7f"><i># return type explicit</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
</div>
<div class="slide">
<h1>Prototypes
</h1><p>No standard prototype language, no CPAN prototype parser!
</p><font color="#7f7f7f"><i># Devel::Declare, Method::Signatures</i></font><font color="#7f7f7f"><i><BR>
</i></font>method hello (Str :<font color="#0000ff">$who</font>, <font color="#007f00">Int</font> :<font color="#0000ff">$age</font> where { <font color="#0000ff"><b>$_</b></font> > 0 }) {<BR>
<font color="#0000ff">$self</font>-><font color="#0000ff">say</font>(<font color="#ffa500">"</font><font color="#ff0000">Hello </font><font color="#0000ff">${who}</font><font color="#ff0000">, I am </font><font color="#0000ff">${age}</font><font color="#ff0000"> years old!</font><font color="#ffa500">"</font>);<BR>
}<BR>
<BR>
<font color="#7f7f7f"><i># Moose</i></font><font color="#7f7f7f"><i><BR>
</i></font>has <font color="#ffa500">'</font><font color="#ff0000">accessor</font><font color="#ffa500">'</font> => (isa => <font color="#007f00">Int</font>, is => <font color="#ffa500">'</font><font color="#ff0000">rw</font><font color="#ffa500">'</font>, default => <font color="#00007f">1</font>);<BR>
<BR>
</div>
<div class="slide">
<h1>Perl's Type System
</h1><p>At first a look at CORE types, not the language:
</p><p><b>SCALAR</b> (non-strict, VB-like): IV, NV, UV, PV, ...
</p><p><b>ARRAY</b> (non-strict): AV
</p><p><b>HASH</b> (non-strict): HV
</p><p><b>Objects</b> ("stashes", @ISA, declaration)
</p></div>
<div class="slide">
<h1>Perl's Type System - SCALAR
</h1><p><b>SCALAR</b> (non-strict, VB-like)
</p><p>multiple types (IV,NV,PV) per variable, context dependent.
</p><p>internally upgraded: IV => PVIV => PVNV
</p></div>
<div class="slide">
<h1>Perl's Type System - SCALAR
</h1><p><b>SCALAR</b> (non-strict, VB-like)
</p><p>multiple types (IV,NV,PV) per variable, context dependent.
</p><p>IV: integer
</p><p><img src=pix/sviv-14.png height=204px width=278px>
</p></div>
<div class="slide">
<h1>Perl's Type System - SCALAR
</h1><p><b>SCALAR</b> (non-strict, VB-like)
</p><p>multiple types (IV,NV,PV) per variable, context dependent.
</p><p>Typed IV: integer unblessed, untied. <code>my int $i;</code> <i>~SV_SMAGIC =<code>></code> SVf_FAKE: no head</i>
</p><p><img src=pix/sviv-14.png height=204px width=278px> => <img src=pix/sviv-new.png height=204px width=278px>
</p></div>
<div class="slide">
<h1>Perl's Type System - SCALAR
</h1><p><b>SCALAR</b> (non-strict, VB-like)
</p><p>multiple types (IV,NV,PV) per variable, context dependent.
</p><p>internally upgraded: IV => NV
</p><p><img src=pix/svnv-14.png height=252px width=288px>
</p></div>
<div class="slide">
<h1>Perl's Type System - SCALAR
</h1><p><b>SCALAR</b> (non-strict, VB-like)
</p><p>multiple types (IV,NV,PV) per variable, context dependent.
</p><p>internally upgraded: IV => NV => PVNV
</p><p><img src=pix/svpvnv-14.png height=264px width=552px>
</p></div>
<div class="slide">
<h1>Perl's Type System - SCALAR
</h1><p><b>SCALAR</b> (non-strict, VB-like)
</p><p>internally upgraded: IV => PVIV => PVNV => "Objects" => Tie
</p><p><img src=pix/svpvmg-14.png>
</p></div>
<div class="slide">
<h1>Perl's Type System - SCALAR
</h1><p><b>"STASH"</b> - Hierarchical symbol table,<br>
used as package name for Objects. i.e. <i>"Class pointer"</i>
</p><p><img src=pix/stash.png>
</p></div>
<div class="slide">
<h1>Perl's Type System - ARRAY
</h1><p><b>ARRAY</b> (non-strict)
</p><p>Keys are integers, Values any SCALAR
</p></div>
<div class="slide">
<h1>Perl's Type System - ARRAY
</h1><p><b>ARRAY</b> (non-strict)
</p><p>Keys are integers, Values any SCALAR
</p><font color="#0000ff">@a</font> = (<font color="#ffa500">"</font><font color="#ff0000">any</font><font color="#ffa500">"</font>, <font color="#00007f">1</font>, <font color="#00007f">2.5006</font>, \&code, [<font color="#ffa500">'</font><font color="#ff0000">arrayref</font><font color="#ffa500">'</font>], {hashref=><font color="#00007f">1</font>});<BR>
<BR>
</div>
<div class="slide">
<h1>Perl's Type System - ARRAY
</h1><p><b>ARRAY</b> (non-strict)
</p><p>Keys are integers, Values any SCALAR - flexible, untyped, big
</p><font color="#0000ff">@a</font> = (<font color="#ffa500">"</font><font color="#ff0000">any</font><font color="#ffa500">"</font>, <font color="#00007f">1</font>, <font color="#00007f">2.5006</font>, \&code, [<font color="#ffa500">'</font><font color="#ff0000">arrayref</font><font color="#ffa500">'</font>], {hashref=><font color="#00007f">1</font>});<BR>
<BR>
<p><img src=pix/av-sv.png>
</p></div>
<div class="slide">
<h1>Typed ARRAY
</h1><p><b>Typed ARRAY</b>s (optional, faster, less space)
</p><p>Keys are integers, Values of one type only (native)
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@a</font>; <font color="#0000ff">$#a</font>=<font color="#00007f">256</font>; <font color="#7f7f7f"><i># pre-allocate: 256 * sizeof(IV)</i></font><font color="#7f7f7f"><i><BR>
</i></font> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@a</font> = (<font color="#00007f">1</font>); <font color="#7f7f7f"><i># non-fixed size: 3 * sizeof(IV)</i></font><font color="#7f7f7f"><i><BR>
</i></font> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@a</font> :const = (<font color="#00007f">1</font>); <font color="#7f7f7f"><i># fixed size: 1 * sizeof(IV)</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<p>Untyped:
</p> <b>my</b> <font color="#0000ff">@a</font>; <font color="#0000ff">$#a</font>=<font color="#00007f">256</font>; <font color="#7f7f7f"><i># pre-allocate: 256 * sizeof(SV)</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
</div>
<div class="slide">
<h1>Typed ARRAY
</h1> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@a</font>;<BR>
<BR>
<p><img src=pix/av-typed.png>
</p><code> AvTYPED && (IOK | NOK | POK) </code></div>
<div class="slide">
<h1>Typed ARRAY
</h1><p><p>
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@a</font>;<BR>
<BR>
<p>Declaration already possible now!
</p> <font color="#c9a7ff">perl</font> -we<font color="#ff0000">'package int; package main; my int @a;'</font><BR>
-e syntax ok<BR>
<BR>
<p><b>int</b> must be a package definition.
</p><p><small>Note: <code>@a</code> is currently declared as <code>int</code>, but not blessed.</small>
</p></div>
<div class="slide">
<h1>Perl's Type System - HASH
</h1><p><b>HASH</b> untyped: flexible, but big
</p><p>Keys any SCALAR, Values any SCALAR
</p> <font color="#0000ff">%h</font> = (<font color="#ffa500">'</font><font color="#ff0000">any</font><font color="#ffa500">'</font> => [<font color="#ffa500">"</font><font color="#ff0000">any</font><font color="#ffa500">"</font>, <font color="#00007f">1</font>, <font color="#00007f">2.5006</font>];<BR>
<font color="#00007f">1</font> => <font color="#00007f">1</font>,<BR>
<font color="#00007f">1.005</font> => <font color="#00007f">2.5</font>);<BR>
<BR>
<p>Internally: Keys are stringified.
</p></div>
<div class="slide">
<h1>Perl's Type System - HASH
</h1><p><b>HASH</b> untyped: flexible<br>
Keys any SCALAR, Values any SCALAR
</p><p><img src=pix/hv-sv.png>
</p></div>
<div class="slide">
<h1>Typed HASH
</h1><p><b>HASH</b> typed: fast, small
</p><p>Keys STRING only, Values typed
</p> <b>my</b> string <font color="#0000ff">%h</font>; <font color="#0000ff">$h</font>{<font color="#ffa500">'</font><font color="#ff0000">x</font><font color="#ffa500">'</font>} = <font color="#ffa500">'</font><font color="#ff0000">string</font><font color="#ffa500">'</font>;<BR>
<b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font>; <font color="#0000ff">$h</font>{<font color="#ffa500">'</font><font color="#ff0000">x</font><font color="#ffa500">'</font>} = <font color="#00007f">1</font>;<BR>
<b>my</b> double <font color="#0000ff">%h</font>; <font color="#0000ff">$h</font>{<font color="#ffa500">'</font><font color="#ff0000">x</font><font color="#ffa500">'</font>} = <font color="#00007f">1.0</font>;<BR>
<BR>
</div>
<div class="slide">
<h1>Typed HASH
</h1><p><b>HASH</b> typed: directer access, small <br>
Keys STRING only, Values typed
</p><p><img src=pix/hv-typed.png>
</p></div>
<div class="slide">
<h1>Typed HASH
</h1><p><b>HASH</b> typed: fast, small
</p><p>Keys STRING only, Values are typed.
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font>; <font color="#0000ff">$h</font>{<font color="#ffa500">'</font><font color="#ff0000">any</font><font color="#ffa500">'</font>} = <font color="#00007f">1</font>;<BR>
<BR>
<font color="#0000ff">$h</font>{<font color="#00007f">2</font>} = <font color="#00007f">1</font>;<BR>
=> Wrong type: hash key <b>no</b> string<BR>
<BR>
<font color="#0000ff">$h</font>{<font color="#ffa500">'</font><font color="#ff0000">2</font><font color="#ffa500">'</font>} = <font color="#ffa500">'</font><font color="#ff0000">1</font><font color="#ffa500">'</font>;<BR>
=> Wrong type: hash value <b>no</b> <font color="#007f00">int</font> <BR>
<BR>
</div>
<div class="slide">
<h1>Perfect HASH
</h1><p>Perfect hashes - <i>guaranteed O(1) lookup, dynamic hash function generation, no collisions</i><br>
Library <b>cmph</b> BDZ algorithm (<i>"RAM hashing"</i>)
</p><ul><li level="1"><code>my %h :const;</code> => untyped perfect hash of unknown size<br>
</li><li level="1"><code>my %h :perfect;</code> => writable perfect hash
</li><li level="1"><code>study %h</code>; => optimize lookup function to perfect hash.
</li></ul><p>study untyped hash => copies the old perl hash (HV)
to new perfect hash (PH).
</p></div>
<div class="slide">
<h1>Perfect HASH
</h1><p>Perfect hash. Should be typed to optimize implementation.
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font> :const = (<font color="#ffa500">'</font><font color="#ff0000">my</font><font color="#ffa500">'</font> => <font color="#00007f">1</font>, <font color="#ffa500">'</font><font color="#ff0000">your</font><font color="#ffa500">'</font> => <font color="#00007f">2</font>);<BR>
<BR>
<p><code>:const</code> hashes are always <code>:perfect</code><br>
No need to study with :const and init on declaration.
</p> <b>my</b> <font color="#0000ff">%h</font> :const = (<font color="#ffa500">'</font><font color="#ff0000">my</font><font color="#ffa500">'</font> => <font color="#00007f">1</font>, <font color="#ffa500">'</font><font color="#ff0000">your</font><font color="#ffa500">'</font> => <font color="#00007f">2</font>);<BR>
<font color="#7f7f7f"><i># untyped: value = SV</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
</div>
<div class="slide">
<h1>Perfect HASH Idioms
</h1><p>- Avoid copy from perl hash to perfect hash.
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font> :perfect;<BR>
<font color="#0000ff">$h</font>{<font color="#0000ff"><b>$_</b></font>}=<font color="#00007f">1</font> <b>for</b> <font color="#0000ff">@h</font>;<BR>
<font color="#007f00">study</font> <font color="#0000ff">%h</font>;<BR>
<BR>
</div>
<div class="slide">
<h1>Perfect HASH Idioms
</h1><p>- Declare size in advance.
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font> :perfect;<BR>
<font color="#007f00">length</font> <font color="#0000ff">%h</font> = <font color="#007f00">length</font> <font color="#0000ff">@h</font>; <font color="#7f7f7f"><i># not legal yet, but should be</i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#0000ff">$h</font>{<font color="#0000ff"><b>$_</b></font>}=<font color="#00007f">1</font> <b>for</b> <font color="#0000ff">@h</font>;<BR>
<font color="#007f00">study</font> <font color="#0000ff">%h</font>;<BR>
<BR>
</div>
<div class="slide">
<h1>Perfect HASH Idioms
</h1><p>- :const hash with computed key => values, without study
</p><p>Idea 1
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font> :const;<BR>
<font color="#007f00">length</font> <font color="#0000ff">%h</font> = <font color="#007f00">length</font> <font color="#0000ff">@keys</font>; <font color="#7f7f7f"><i># not legal yet, but should be</i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#0000ff">$h</font>{<font color="#0000ff"><b>$_</b></font>} = <font color="#0000ff">$i</font>++ <b>for</b> <font color="#0000ff">@keys</font>;<BR>
<BR>
<p>Init until length is filled
</p></div>
<div class="slide">
<h1>Perfect HASH Idioms
</h1><p>- :const hash with computed key => values, without study
</p><p>Idea 2
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font> :const = <font color="#007f00">map</font> { <font color="#0000ff">$h</font>{<font color="#0000ff"><b>$_</b></font>} => <font color="#0000ff">$i</font>++} <font color="#0000ff">@keys</font>;<BR>
=><BR>
<b>my</b> <font color="#007f00">int</font> <font color="#0000ff">%h</font> :const;<BR>
{ <font color="#0000ff">$h</font>{<font color="#0000ff"><b>$_</b></font>} = <font color="#0000ff">$i</font>++ <b>for</b> <font color="#0000ff">@keys</font>; }<BR>
<BR>
<p>Initialization on next expression, usually a block.
</p></div>
<div class="slide">
<h1>Perl's Type System - OBJECTS
</h1><p><b>OBJECTS</b>: typed, but dynamic
</p><p>run-time changable, mostly no compile-time optimizations possible.
</p><p>Features: STASH ("class hash"), @ISA (mro), DESTROY
</p></div>
<div class="slide">
<h1>Perl's Type System - OBJECTS
</h1><p><b>OBJECTS</b>: typed, but dynamic.
</p><p>Class by STASH, Inheritance by @ISA (mro), magic DESTROY and CLONE methods.
</p><p>Four method calls possible:
</p><ul><li level="1">Class->method()
</li><li level="1">$object->method()
</li><li level="1">Class->$method()
</li><li level="1">$object->$method()
</li></ul></div>
<div class="slide">
<h1>Compilation of a function
</h1><font color="#007f00">Class::sub</font>(ARGS...)<BR>
<BR>
<code> pushmark <br>
ARGS... <br>
gv => GV *Class::sub <br>
entersub </code><p>Class->method() <br>
$object->method() <br>
Class->$method() <br>
$object->$method()
</p></div>
<div class="slide">
<h1>Compilation of a static method call
</h1><p>Class::sub() <br>
</p>Class->method(ARGS...)<BR>
<BR>
<code> pushmark <br>
const => PV "Class" <br>
ARGS... <br>
method_named => PV "method" <br>
entersub </code><p>$object->method() <br>
Class->$method() <br>
$object->$method()
</p></div>
<div class="slide">
<h1>Compilation of a method call
</h1><font color="#0000ff">$object</font>-><font color="#0000ff">method</font>(ARGS...)<BR>
<BR>
<code> pushmark <br>
padsv => GV *object <br>
ARGS... <br>
method_named => PV "method" <br>
entersub </code></div>
<div class="slide">
<h1>Compilation of a method call
</h1>Class-><font color="#0000ff">$method</font>(ARGS...)<BR>
<BR>
<code> pushmark <br>
const => PV "Class" <br>
ARGS... <br>
method => GV *method <br>
entersub </code></div>
<div class="slide">
<h1>Compilation of a method call
</h1><font color="#0000ff">$object</font>-><font color="#0000ff">$method</font>(ARGS...)<BR>
<BR>
<code> pushmark <br>
padsv => GV *object <br>
ARGS... <br>
method => GV *method <br>
entersub </code></div>
<div class="slide">
<h1>Optimization of a static method call
</h1>Class->method()<BR>
<BR>
<code> pushmark <br>
const => PV "Class" <br>
ARGS... <br>
method_named => PV "method" <br>
entersub <br>
=> <br>
pushmark <br>
const => PV "Class" <br>
ARGS... <br>
gv => GV *Class::method <br>
entersub </code></div>
<div class="slide">
<h1>Optimization of a static method call
</h1>Class->method(...) => &<font color="#007f00">Class::method</font>(<font color="#ffa500">'</font><font color="#ff0000">Class</font><font color="#ffa500">'</font>, ...)<BR>
<BR>
<b>if</b> <font color="#007f00">defined</font> &<font color="#007f00">Class::method</font><BR>
<BR>
<p>or <code>package Class</code> <b>:locked</b> or in Moose immutable.<br>
i.e. not changed at run-time.
</p><p>=> 4% faster method calls.
</p><p>Note: <code>@Class::ISA</code> <b>:const</b> = <code>qw(bla);</code> does not help.
</p></div>
<div class="slide">
<h1>Optimization of other method calls
</h1><p><b>Dynamic</b> method calls are possible to optimize in a similar way,
if the object is <b>declared</b> - known class at compile-time.
</p> <b>my</b> <b>My</b>::Class <font color="#0000ff">$object</font> = <b>My</b>::Class->new;<BR>
<font color="#0000ff">$object</font>-><font color="#0000ff">call</font>();<BR>
<BR>
<b>my</b> <b>My</b>::Class <font color="#0000ff">$object</font> = <b>My</b>::ParentClass->new;<BR>
<font color="#007f00">bless</font> <font color="#0000ff">$object</font>, <font color="#ffa500">'</font><font color="#ff0000">My::Class</font><font color="#ffa500">'</font>;<BR>
<font color="#0000ff">$object</font>-><font color="#0000ff">call</font>();<BR>
<BR>
<p>Inherited methods are optimizable if all classes in path to the
final class are <b>:locked</b>, resp. <b>immutable</b>.
</p></div>
<div class="slide">
<h1>Summary so far
</h1><p>All this is possible now, without changing the language.
</p><p>Just optimized implementations are missing.
</p><p>I heard that in July 2011 Moose methods of immutable classes are
going to be inlined, but what I saw so far it's not using
optree changes like these to speed it up.
</p></div>
<div class="slide">
<h1>More optimizations
</h1><p>More compile-time optimizations.
</p><p><b>:const</b> for variables
</p><p><b>:locked</b> for packages: const <code>@ISA</code>, no run-time created methods.
</p></div>
<div class="slide">
<h1>use types;
</h1><p><b>types</b> is Artur Bergman's compile-time checking attempt from 2002,
after the <b>compiler</b>, <b>B::Generate</b> and <b>optimize</b>.
</p><p>And before <b>optimizer</b>, which uses <b>types</b> to improve the optree.
</p></div>
<div class="slide">
<h1>use types;
</h1><p><b>types</b> does compile-time type-checking only.
</p><p>compile-time type-optimizations in <b>optimizer</b>.
</p><p>Problem: <b>slower</b>, not faster.
</p></div>
<div class="slide">
<h1>use types;
</h1><p>The idea is to make programs with <code>use types;</code>
</p><p><b>faster</b>, not slower.
</p><p>And define basic scalar types from CORE
</p><p><code>int</code>, <code>double</code> and <code>string</code>
</p></div>
<div class="slide">
<h1>B::CC
</h1><p>The same types and declarations are used in B::CC also
to optimize types even further.
</p></div>
<div class="slide">
<h1>B::CC - optimizing perl compiler
</h1><p>B::CC also needs a syntax to optionally declare simple types:
</p><p><b>int</b> and <b>double</b> (strict)
</p><p>So far it was done by magic variable name suffices: <code>$a_i</code>, <code>$n_d</code>;
</p><p>faster, <b>much</b> faster
</p></div>
<div class="slide">
<h1>B::CC - User Type declarations
</h1><p>Strict types as class, and optional type hints as attributes.
</p> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">$foo</font> :const;<BR>
<BR>
<p>With <code>use types</code> you get <b>type-declarations</b>, <br>
partial <b>type-safety</b>, and <br>
<b>type optimizations</b> at compile-time.
</p></div>
<div class="slide">
<h1>SUMMARY
</h1> <b>my</b> double <font color="#0000ff">$foo</font> = <font color="#ffa500">"</font><font color="#ff0000">string</font><font color="#ffa500">"</font>; <font color="#7f7f7f"><i>#compile-time error </i></font><font color="#7f7f7f"><i><BR>
</i></font> <b>sub </b><font color="#007f00">foo</font> (<font color="#007f00">int</font> <font color="#0000ff">$foo</font>) { <b>my</b> (<font color="#0000ff">$foo</font>) = <font color="#0000ff">@_</font> }; <BR>
foo(<font color="#ffa500">"</font><font color="#ff0000">hi</font><font color="#ffa500">"</font>); <font color="#7f7f7f"><i>#compile-time Type mismatch error </i></font><font color="#7f7f7f"><i><BR>
</i></font> <BR>
<b>my</b> <font color="#007f00">int</font> <font color="#0000ff">$int</font>; <BR>
<b>sub </b><font color="#007f00">foo</font> { <b>my</b> double <font color="#0000ff">$foo</font>; <b>return</b> <font color="#0000ff">$foo</font> } <BR>
<font color="#0000ff">$int</font> = <font color="#0000ff">$foo</font>; <font color="#7f7f7f"><i># compile-time Type mismatch error </i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@array</font> = (0.<font color="#00007f">.10</font>); <font color="#7f7f7f"><i># optimized internal representation </i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#0000ff">$array</font>[<font color="#00007f">2</font>] = <font color="#00007f">2</font>; <font color="#7f7f7f"><i># no SV, just the raw int at slot 2. </i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
</div>
<div class="slide">
<h1>SUMMARY
</h1> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@array</font> :const = (0.<font color="#00007f">.10</font>); <BR>
<font color="#7f7f7f"><i># even more optimized internal representation </i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#0000ff">$array</font>[<font color="#00007f">2</font>] = <font color="#00007f">2</font>; <font color="#7f7f7f"><i># int @array is readonly </i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#0000ff">$array</font>[<font color="#00007f">2</font>] = <font color="#ffa500">'</font><font color="#ff0000">2</font><font color="#ffa500">'</font>; <font color="#7f7f7f"><i># compile-time const error </i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<b>my</b> string <font color="#0000ff">%stash</font> :perfect = <BR>
(foo => <font color="#ffa500">'</font><font color="#ff0000">str1</font><font color="#ffa500">'</font>, bar => <font color="#ffa500">'</font><font color="#ff0000">str2</font><font color="#ffa500">'</font>); <font color="#7f7f7f"><i># perfect hash (stashes)</i></font><font color="#7f7f7f"><i><BR>
</i></font> ; <font color="#7f7f7f"><i># more init... </i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#007f00">study</font> <font color="#0000ff">%stash</font>; <font color="#7f7f7f"><i># initialization finished </i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<font color="#007f00">print</font> <font color="#0000ff">$stash</font>{foo}; <font color="#7f7f7f"><i># faster lookup O(1) </i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#0000ff">$stash</font>{new} = <font color="#00007f">1</font>; <font color="#7f7f7f"><i># compile-time Type mismatch error</i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
</div>
<div class="slide">
<h1>SUMMARY
</h1> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">$i</font> :double; <font color="#7f7f7f"><i># declares a IV with SVf_NOK. </i></font><font color="#7f7f7f"><i><BR>
</i></font> <b>my</b> <font color="#0000ff">$i</font>:<font color="#007f00">int</font>:double; <font color="#7f7f7f"><i># same but without type-check </i></font><font color="#7f7f7f"><i><BR>
</i></font> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">$i</font>; <font color="#7f7f7f"><i># declares an IV. </i></font><font color="#7f7f7f"><i><BR>
</i></font> <b>my</b> <font color="#0000ff">$i</font>:<font color="#007f00">int</font>; <font color="#7f7f7f"><i># same but without type-check </i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
<b>my</b> <font color="#007f00">int</font> <font color="#0000ff">$i</font> :string; <font color="#7f7f7f"><i># declares a PVIV. </i></font><font color="#7f7f7f"><i><BR>
</i></font> <b>my</b> <font color="#007f00">int</font> <font color="#0000ff">@array</font> :unsigned = (0.<font color="#00007f">.4</font>); <BR>
<font color="#7f7f7f"><i># Will be used as c var in faster arithmetic and cmp. </i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#7f7f7f"><i># Will use no SV value slot, just the direct value. </i></font><font color="#7f7f7f"><i><BR>
</i></font> <BR>
<b>my</b> string <font color="#0000ff">%hash</font> :const = (foo => <font color="#ffa500">'</font><font color="#ff0000">any</font><font color="#ffa500">'</font>, bar => <font color="#ffa500">'</font><font color="#ff0000">any</font><font color="#ffa500">'</font>); <BR>
<font color="#7f7f7f"><i># declare string keys only </i></font><font color="#7f7f7f"><i><BR>
</i></font> <font color="#7f7f7f"><i># generate as read-only perfect hash. </i></font><font color="#7f7f7f"><i><BR>
</i></font><BR>
</div>
<div class="slide">
<h1>Questions?
</h1></div>
<div class="slide">
<h1>Questions?
</h1><p><a href="http://blogs.perl.org/users/rurban/2011/02/use-types.html">http://blogs.perl.org/users/rurban/2011/02/use-types.html</a>
</p></div></body></html>