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Sub::Quote(3pm) User Contributed Perl Documentation Sub::Quote(3pm)
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 Mengue (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/>.
perl v5.30.0 2019-10-13 Sub::Quote(3pm)
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On Apache
Under GNU General Public License
2025-11-04 11:35 @216.73.216.210 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)