/ 
Moo-1.003001
River stage four • 2274 direct dependents • 5577 total dependents
/ 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.

options

  • no_install

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

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.

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.

inlinify

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

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.

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.

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.

strictures

Sub::Quote compiles quoted subs in an environment where use strictures is in effect. strictures enables strict and FATAL warnings.

The following dies Use of uninitialized value in print...

no warnings;
quote_sub 'Silly::kitty', q{ print undef };

If you need to disable parts of strictures, do it within the quoted sub:

quote_sub 'Silly::kitty', q{ no warnings; print undef };

SUPPORT

See Moo for support and contact information.

AUTHORS

See Moo for authors.

COPYRIGHT AND LICENSE

See Moo for the copyright and license.