/usr/share/perl5/Sub/Quote.pm is in libmoo-perl 0.009013-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 | package Sub::Quote;
use strictures 1;
sub _clean_eval { eval $_[0] }
use Sub::Defer;
use B 'perlstring';
use Scalar::Util qw(weaken);
use base qw(Exporter);
our @EXPORT = qw(quote_sub unquote_sub quoted_from_sub);
our %QUOTE_OUTSTANDING;
our %QUOTED;
our %WEAK_REFS;
sub capture_unroll {
my ($from, $captures, $indent) = @_;
join(
'',
map {
/^([\@\%\$])/
or die "capture key should start with \@, \% or \$: $_";
(' ' x $indent).qq{my ${_} = ${1}{${from}->{${\perlstring $_}}};\n};
} keys %$captures
);
}
sub inlinify {
my ($code, $args, $extra, $local) = @_;
my $do = 'do { '.($extra||'');
if (my ($code_args, $body) = $code =~ / +my \(([^)]+)\) = \@_;(.*)$/s) {
if ($code_args eq $args) {
$do.$body.' }'
} else {
$do.'my ('.$code_args.') = ('.$args.'); '.$body.' }';
}
} else {
$do.($local ? 'local ' : '').'@_ = ('.$args.'); '.$code.' }';
}
}
sub _unquote_all_outstanding {
return unless %QUOTE_OUTSTANDING;
my ($assembled_code, @assembled_captures, @localize_these) = '';
# we sort the keys in order to make debugging more predictable
foreach my $outstanding (sort keys %QUOTE_OUTSTANDING) {
my ($name, $code, $captures) = @{$QUOTE_OUTSTANDING{$outstanding}};
push @localize_these, $name if $name;
my $make_sub = "{\n";
if (keys %$captures) {
my $ass_cap_count = @assembled_captures;
$make_sub .= capture_unroll("\$_[1][${ass_cap_count}]", $captures, 2);
push @assembled_captures, $captures;
}
my $o_quoted = perlstring $outstanding;
$make_sub .= (
$name
# disable the 'variable $x will not stay shared' warning since
# we're not letting it escape from this scope anyway so there's
# nothing trying to share it
? " no warnings 'closure';\n sub ${name} {\n"
: " \$Sub::Quote::QUOTED{${o_quoted}}[3] = sub {\n"
);
$make_sub .= $code;
$make_sub .= " }".($name ? '' : ';')."\n";
if ($name) {
$make_sub .= " \$Sub::Quote::QUOTED{${o_quoted}}[3] = \\&${name}\n";
}
$make_sub .= "}\n";
$assembled_code .= $make_sub;
}
my $debug_code = $assembled_code;
if (@localize_these) {
$debug_code =
"# localizing: ".join(', ', @localize_these)."\n"
.$assembled_code;
$assembled_code = join("\n",
(map { "local *${_};" } @localize_these),
'eval '.perlstring($assembled_code).'; die $@ if $@;'
);
} else {
$ENV{SUB_QUOTE_DEBUG} && warn $assembled_code;
}
$assembled_code .= "\n1;";
{
local $@;
unless (_clean_eval $assembled_code, \@assembled_captures) {
die "Eval went very, very wrong:\n\n${debug_code}\n\n$@";
}
}
$ENV{SUB_QUOTE_DEBUG} && warn $debug_code;
%QUOTE_OUTSTANDING = ();
}
sub quote_sub {
# HOLY DWIMMERY, BATMAN!
# $name => $code => \%captures => \%options
# $name => $code => \%captures
# $name => $code
# $code => \%captures => \%options
# $code
my $options =
(ref($_[-1]) eq 'HASH' and ref($_[-2]) eq 'HASH')
? pop
: {};
my $captures = pop if ref($_[-1]) eq 'HASH';
undef($captures) if $captures && !keys %$captures;
my $code = pop;
my $name = $_[0];
my $outstanding;
my $deferred = defer_sub +($options->{no_install} ? undef : $name) => sub {
unquote_sub($outstanding);
};
$outstanding = "$deferred";
$QUOTE_OUTSTANDING{$outstanding} = $QUOTED{$outstanding} = [
$name, $code, $captures
];
weaken($WEAK_REFS{$outstanding} = $deferred);
return $deferred;
}
sub quoted_from_sub {
my ($sub) = @_;
$WEAK_REFS{$sub||''} and $QUOTED{$sub||''};
}
sub unquote_sub {
my ($sub) = @_;
_unquote_all_outstanding;
$QUOTED{$sub}[3];
}
1;
=head1 NAME
Sub::Quote - efficient generation of subroutines via string eval
=head1 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
=head1 DESCRIPTION
This package provides performant ways to generate subroutines from strings.
=head1 SUBROUTINES
=head2 quote_sub
my $coderef = quote_sub 'Foo::bar', q{ print $x++ . "\n" }, { '$x' => \0 };
Arguments: ?$name, $code, ?\%captures, ?\%options
C<$name> is the subroutine where the coderef will be installed.
C<$code> is a string that will be turned into code.
C<\%captures> is a hashref of variables that will be made available to the
code. See the L</SYNOPSIS>'s C<Silly::dagron> for an example using captures.
=head3 options
=over 2
=item * no_install
B<Boolean>. Set this option to not install the generated coderef into the
passed subroutine name on undefer.
=back
=head2 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.
=head2 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.
=head2 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 B<Boolean> representing whether or not to localize the
arguments.
=head2 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
L</inlinify>. The keys are the names of the variables and the values are (duh)
the values. Note that references work as values.
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