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Sub::Quote(3)                        User Contributed Perl Documentation                       Sub::Quote(3)



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.  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.  Note that for performance reasons all quoted subs
       declared so far will be globally unquoted/parsed in a single eval. This means that if you have a
       syntax error in one of your quoted subs you may find out when some other sub is unquoted.

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

       Generates a snippet of code which is suitable to be used as a prelude for "inlinify".  The keys are
       the names of the variables and the values are (duh) the values.  Note that references work as values.

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.



perl v5.16.2                                     2012-07-04                                    Sub::Quote(3)