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|
use strict; use warnings;
package Class::Field;
our $VERSION = '0.24';
use base 'Exporter';
our @EXPORT_OK = qw(field const);
use Encode;
my %code = (
sub_start =>
"sub {\n local \*__ANON__ = \"%s::%s\";\n",
set_default =>
" \$_[0]->{%s} = %s\n unless exists \$_[0]->{%s};\n",
init =>
" return \$_[0]->{%s} = do { my \$self = \$_[0]; %s }\n" .
" unless \$#_ > 0 or defined \$_[0]->{%s};\n",
weak_init =>
" return do {\n" .
" \$_[0]->{%s} = do { my \$self = \$_[0]; %s };\n" .
" Scalar::Util::weaken(\$_[0]->{%s}) if ref \$_[0]->{%s};\n" .
" \$_[0]->{%s};\n" .
" } unless \$#_ > 0 or defined \$_[0]->{%s};\n",
return_if_get =>
" return \$_[0]->{%s} unless \$#_ > 0;\n",
set =>
" \$_[0]->{%s} = \$_[1];\n",
weaken =>
" Scalar::Util::weaken(\$_[0]->{%s}) if ref \$_[0]->{%s};\n",
sub_end =>
" return \$_[0]->{%s};\n}\n",
);
sub field {
my $package = caller;
my ($args, @values) = do {
no warnings;
local *boolean_arguments = sub { (qw(-weak)) };
local *paired_arguments = sub { (qw(-package -init)) };
Class::Field->parse_arguments(@_);
};
my ($field, $default) = @values;
$package = $args->{-package} if defined $args->{-package};
die "Cannot have a default for a weakened field ($field)"
if defined $default && $args->{-weak};
return if defined &{"${package}::$field"};
require Scalar::Util if $args->{-weak};
my $default_string =
( ref($default) eq 'ARRAY' and not @$default )
? '[]'
: (ref($default) eq 'HASH' and not keys %$default )
? '{}'
: default_as_code($default);
my $code = sprintf $code{sub_start}, $package, $field;
if ($args->{-init}) {
if ($args->{-weak}) {
$code .= sprintf $code{weak_init}, $field, $args->{-init}, ($field) x 4;
} else {
$code .= sprintf $code{init}, $field, $args->{-init}, $field;
}
}
$code .= sprintf $code{set_default}, $field, $default_string, $field
if defined $default;
$code .= sprintf $code{return_if_get}, $field;
$code .= sprintf $code{set}, $field;
$code .= sprintf $code{weaken}, $field, $field
if $args->{-weak};
$code .= sprintf $code{sub_end}, $field;
my $sub = eval $code;
die $@ if $@;
no strict 'refs';
use utf8;
my $method = "${package}::$field";
$method = Encode::decode_utf8($method);
*{$method} = $sub;
return $code if defined wantarray;
}
sub default_as_code {
no warnings 'once';
require Data::Dumper;
local $Data::Dumper::Sortkeys = 1;
my $code = Data::Dumper::Dumper(shift);
$code =~ s/^\$VAR1 = //;
$code =~ s/;$//;
return $code;
}
sub const {
my $package = caller;
my ($args, @values) = do {
no warnings;
local *paired_arguments = sub { (qw(-package)) };
Class::Field->parse_arguments(@_);
};
my ($field, $default) = @values;
$package = $args->{-package} if defined $args->{-package};
no strict 'refs';
return if defined &{"${package}::$field"};
*{"${package}::$field"} = sub { $default }
}
sub parse_arguments {
my $class = shift;
my ($args, @values) = ({}, ());
my %booleans = map { ($_, 1) } $class->boolean_arguments;
my %pairs = map { ($_, 1) } $class->paired_arguments;
while (@_) {
my $elem = shift;
if (defined $elem and defined $booleans{$elem}) {
$args->{$elem} = (@_ and $_[0] =~ /^[01]$/)
? shift
: 1;
}
elsif (defined $elem and defined $pairs{$elem} and @_) {
$args->{$elem} = shift;
}
else {
push @values, $elem;
}
}
return wantarray ? ($args, @values) : $args;
}
sub boolean_arguments { () }
sub paired_arguments { () }
1;
|
