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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.  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@shadowcat.co.uk>


CONTRIBUTORS

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

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

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

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

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

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

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

       dolmen - Olivier MenguA(C) (cpan:DOLMEN) <dolmen@cpan.org>

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

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

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

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

       djerius - Diab Jerius (cpan:DJERIUS) <djerius@cfa.harvard.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                      2019-10-01                     Sub::Quote(3)

sub-quote 2.6.6 - Generated Fri Jul 24 15:50:55 CDT 2020
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