in reply to Export Constants Common to Lots of Packages

If you wished to use true constants, 
use strict;
use warnings;

package ddd;

require Exporter;
our @ISA    = qw( Exporter );
our @EXPORT = qw( APPLE PEAR );

use constant APPLE => "funny";
use constant PEAR  => "bad";

1;

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use strict;
use warnings;

use ddd;

print "APPLE = " . APPLE . "\n";

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Re^2: Export Constants Common to Lots of Packages
by jffry (Hermit) on Nov 29, 2005 at 19:57 UTC
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      Same here. At work, we've recently removed "use constant" from our code and converted to Readonly due to Damian's advice. It's really cleaned up a lot of our code.

      Unfortunately, there are some bugs in how Perl handle tie which Readonly exposes. For example, the following prints "no":

      #!/usr/bin/perl -l

use strict;
use warnings;

use Readonly;
Readonly my $VAR => 'SEARCH';

foreach my $var ($VAR) {
    print +($var eq $VAR) ? 'yes' : 'no';
}

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      Clearly that's wrong, but it's related to Perl's tie mechanism and not Readonly. As a workaround:

       print +($var.'' eq $VAR.'') ? 'yes' : 'no';

      That's ugly as sin, but it works :(

      Cheers,
      Ovid

      New address of my CGI Course.

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        Would "$var" eq "$VAR" work?
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      Constants are different than normal variables, so I like how use constant constants look differently (due to lack of a sigil). Isn't that one of Perl's mantras?

      Readonly uses tie. Tied variables are slower, and they behave erratically in a few situations.

      On the other hand, Readonly works on types other than scalar.

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