Optimized constants without namespace pollution? constant::co?

This doesn't work

#!/usr/bin/perl --
package NameSpace;

use constant 1  +{qw{ RO 1 SHAM 2 BO 3 }};

BEGIN { print "before clean ", join ' ', keys \%NameSpace::, "\n"; }

use namespace::clean;
use namespace::clean qw[ RO SHAM BO ];

BEGIN { print "after clean ", join ' ', keys \%NameSpace::, "\n"; }

printf  "SHAM?? %s  \n", SHAM();
1;
__END__
$ perl -e " do 'yo'; print NameSpace::SHAM() "
before clean BEGIN RO BO SHAM
after clean BEGIN __NAMESPACE_CLEAN_STORAGE RO BO SHAM
SHAM?? 2
2
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I think it should be possible to accomplish using Devel::Declare or maybe another way, but I don't know how

update: I found PerlX::QuoteOperator but it doesn't constant-ize (not optimized):

#!/usr/bin/perl --
package NameSpace;
{

    use PerlX::QuoteOperator CO => {
        -emulate => 'q', 
        -with    => do {
            my %CO = qw[ RO 1 SHAM 2 BO 3 ];
            sub ($) { $CO{ uc $_[0]} };
        }, 
    };

    print CO(RO), "\n";
#~     print CO'SHAM', "\n"; ## Can't find string terminator "'" anywh
+ere before EOF 
    print CO"SHAM", "\n";
    print CO/BO/, "\n";
}

print "OUTSIDE", CO(SHAM), "\n";
eval q{
    print "from eval ", CO(SHAM), "\n";
} or die $@;
__END__
1
2
3
OUTSIDE2
from eval 2
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It CO"SHAM" becomes/Deparses as CO('SHAM')

Can Devel::Declare make constants, ie CO(SHAM) becomes "SHAM" instead of CO("SHAM") ?

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Re: Optimized constants without namespace pollution? constant::co?
by tobyink (Monsignor) on Feb 16, 2013 at 11:40 UTC

You're overthinking this. constant and namespace::clean do play nicely together...

use 5.010;
use strict;
use warnings;
use Test::More;

{
    package Foo;
    use constant XYZ => 123;
    use namespace::clean;
    sub add_xyz { shift; return XYZ + $_[0] };
}

ok( !Foo->can('XYZ'),        'constant was cleaned away' );
ok(  Foo->can('add_xyz'),    'method still exists' );
is(  Foo->add_xyz(100), 223, 'method works properly' );

done_testing;
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The problem with your tests is that you assume that use namespace::clean deletes subs immediately. It does not. It uses B::Hooks::EndOfScope to wipe the subs away when the enclosing scope is finished compiling.

package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name

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Optimized constants without namespace pollution? constant::co?

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