phpman > perldoc > Sub::Quote

NAME
    Sub::Quote - Efficient generation of subroutines via string eval

SYNOPSIS
     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

DESCRIPTION
    This package provides performant ways to generate subroutines from strings.

SUBROUTINES
  quote_sub
     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.

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

    "no_defer"
      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.

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

    "hints"
      The value of $^H to use for the code being evaluated. This captures the settings of the strict
      pragma. If not specified, the value from the calling code will be used.

    "warning_bits"
      The value of "${^WARNING_BITS}" to use for the code being evaluated. This captures the
      warnings set. If not specified, the warnings from the calling code will be used.

    "%^H"
      The value of "%^H" to use for the code being evaluated. This captures additional pragma
      settings. If not specified, the value from the calling code will be used if possible (on perl
      5.10+).

    "attributes"
      The "Subroutine Attributes" in perlsub to apply to the sub generated. Should be specified as
      an array reference. The attributes will be applied to both the generated sub and the deferred
      wrapper, if one is used.

    "file"
      The apparent filename to use for the code being evaluated.

    "line"
      The apparent line number to use for the code being evaluated.

  unquote_sub
     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.

  quoted_from_sub
     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.

  inlinify
     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.

  quotify
     my $quoted_value = quotify $value;

    Quotes a single (non-reference) scalar value for use in a code string. The result should
    reproduce the original value, including strings, undef, integers, and floating point numbers.
    The resulting floating point numbers (including infinites and not a number) should be precisely
    equal to the original, if possible. The exact format of the resulting number should not be
    relied on, as it may include hex floats or math expressions.

  capture_unroll
     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.

  qsub
     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.

  sanitize_identifier
     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.

ENVIRONMENT
  SUB_QUOTE_DEBUG
    Causes code to be output to "STDERR" before being evaled. Several forms are supported:

    1   All subs will be output.

    "/foo/"
        Subs will be output if their code matches the given regular expression.

    "simple_identifier"
        Any sub with the given name will be output.

    "Full::identifier"
        A sub matching the full name will be output.

    "Package::Name::"
        Any sub in the given package (including anonymous subs) will be output.

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

  return
    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;
          $morecode
        };
        <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.

  pragmas
    "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.

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

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

    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>

AUTHOR
    mst - Matt S. Trout (cpan:MSTROUT) <mst AT shadowcat.uk>

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

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

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

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

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

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

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

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

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

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

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

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

    djerius - Diab Jerius (cpan:DJERIUS) <djerius AT cfa.edu>

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

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