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.

       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.

   quotify
        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()".

   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.

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
       See Moo for support and contact information.

AUTHORS
       See Moo for authors.

COPYRIGHT AND LICENSE
       See Moo for the copyright and license.



perl v5.20.1                                2014-10-22                            Sub::Quote(3pm)