Sub::Quote(3) | User Contributed Perl Documentation | Sub::Quote(3) |
Sub::Quote - Efficient generation of subroutines via string eval
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
This package provides performant ways to generate subroutines from strings.
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
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.
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.
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.
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.
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.
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.
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.
Causes code to be output to "STDERR" before being evaled. Several forms are supported:
Much of this is just string-based code-generation, and as a result, a few caveats apply.
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.
"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.
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>
mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
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 Mengué (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 (c) 2010-2016 the Sub::Quote "AUTHOR" and "CONTRIBUTORS" as listed above.
This library is free software and may be distributed under the same terms as perl itself. See <http://dev.perl.org/licenses/>.
2019-10-01 | perl v5.34.0 |