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Graham Knop
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Sub::Quote - efficient generation of subroutines via string eval


 package Silly;

 use Sub::Quote qw(quote_sub unquote_sub quoted_from_sub);

 quote_sub 'Silly::kitty', q{ print "meow" };

 quote_sub 'Silly::doggy', q{ print "woof" };

 my $sound = 0;

 quote_sub 'Silly::dagron',
   q{ print ++$sound % 2 ? 'burninate' : 'roar' },
   { '$sound' => \$sound };

And elsewhere:

 Silly->kitty;  # meow
 Silly->doggy;  # woof
 Silly->dagron; # burninate
 Silly->dagron; # roar
 Silly->dagron; # burninate


This package provides performant ways to generate subroutines from strings.



 my $coderef = quote_sub 'Foo::bar', q{ print $x++ . "\n" }, { '$x' => \0 };

Arguments: ?$name, $code, ?\%captures, ?\%options

$name is the subroutine where the coderef will be installed.

$code is a string that will be turned into code.

\%captures is a hashref of variables that will be made available to the code. The keys should be the full name of the variable to be made available, including the sigil. The values should be references to the values. The variables will contain copies of the values. See the "SYNOPSIS"'s Silly::dagron for an example using captures.

Exported by default.



Boolean. Set this option to not install the generated coderef into the passed subroutine name on undefer.


Boolean. Prevents a Sub::Defer wrapper from being generated for the quoted sub. If the sub will most likely be called at some point, setting this is a good idea. For a sub that will most likely be inlined, it is not recommended.


The package that the quoted sub will be evaluated in. If not specified, the sub calling quote_sub will be used.


 my $coderef = unquote_sub $sub;

Forcibly replace subroutine with actual code.

If $sub is not a quoted sub, this is a no-op.

Exported by default.


 my $data = quoted_from_sub $sub;

 my ($name, $code, $captures, $compiled_sub) = @$data;

Returns original arguments to quote_sub, plus the compiled version if this sub has already been unquoted.

Note that $sub can be either the original quoted version or the compiled version for convenience.

Exported by default.


 my $prelude = capture_unroll '$captures', {
   '$x' => 1,
   '$y' => 2,
 }, 4;

 my $inlined_code = inlinify q{
   my ($x, $y) = @_;

   print $x + $y . "\n";
 }, '$x, $y', $prelude;

Takes a string of code, a string of arguments, a string of code which acts as a "prelude", and a Boolean representing whether or not to localize the arguments.


 my $quoted_value = quotify $value;

Quotes a single (non-reference) scalar value for use in a code string. Numbers aren't treated specially and will be quoted as strings, but undef will quoted as undef().


 my $prelude = capture_unroll '$captures', {
   '$x' => 1,
   '$y' => 2,
 }, 4;

Arguments: $from, \%captures, $indent

Generates a snippet of code which is suitable to be used as a prelude for "inlinify". $from is a string will be used as a hashref in the resulting code. The keys of %captures are the names of the variables and the values are ignored. $indent is the number of spaces to indent the result by.


 my $hash = {
  coderef => qsub q{ print "hello"; },
  other   => 5,

Arguments: $code

Works exactly like "quote_sub", but includes a prototype to only accept a single parameter. This makes it easier to include in hash structures or lists.

Exported by default.


 my $var_name = '$variable_for_' . sanitize_identifier('@name');
 quote_sub qq{ print \$${var_name} }, { $var_name => \$value };

Arguments: $identifier

Sanitizes a value so that it can be used in an identifier.


Much of this is just string-based code-generation, and as a result, a few caveats apply.


Calling return from a quote_sub'ed sub will not likely do what you intend. Instead of returning from the code you defined in quote_sub, it will return from the overall function it is composited into.

So when you pass in:

   quote_sub q{  return 1 if $condition; $morecode }

It might turn up in the intended context as follows:

  sub foo {

    <important code a>
    do {
      return 1 if $condition;
    <important code b>


Which will obviously return from foo, when all you meant to do was return from the code context in quote_sub and proceed with running important code b.


Sub::Quote preserves the environment of the code creating the quoted subs. This includes the package, strict, warnings, and any other lexical pragmas. This is done by prefixing the code with a block that sets up a matching environment. When inlining Sub::Quote subs, care should be taken that user pragmas won't effect the rest of the code.


Users' IRC: #moose on irc.perl.org

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Development and contribution IRC: #web-simple on irc.perl.org

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Bugtracker: https://rt.cpan.org/Public/Dist/Display.html?Name=Sub-Quote

Git repository: git://github.com/moose/Sub-Quote.git

Git browser: https://github.com/moose/Sub-Quote


mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>


frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>

ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>

Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@googlemail.com>

tobyink - Toby Inkster (cpan:TOBYINK) <tobyink@cpan.org>

haarg - Graham Knop (cpan:HAARG) <haarg@cpan.org>

bluefeet - Aran Deltac (cpan:BLUEFEET) <bluefeet@gmail.com>

ether - Karen Etheridge (cpan:ETHER) <ether@cpan.org>

dolmen - Olivier Mengué (cpan:DOLMEN) <dolmen@cpan.org>

alexbio - Alessandro Ghedini (cpan:ALEXBIO) <alexbio@cpan.org>

getty - Torsten Raudssus (cpan:GETTY) <torsten@raudss.us>

arcanez - Justin Hunter (cpan:ARCANEZ) <justin.d.hunter@gmail.com>

kanashiro - Lucas Kanashiro (cpan:KANASHIRO) <kanashiro.duarte@gmail.com>


Copyright (c) 2010-2016 the Sub::Quote "AUTHOR" and "CONTRIBUTORS" as listed above.


This library is free software and may be distributed under the same terms as perl itself. See http://dev.perl.org/licenses/.