Re: List with qw and without

William wrote:
package MyConfig;
use constant (DOCUMENT_ROOT => "/var/www/");
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(DOCUMENT_ROOT); # This works
#our @EXPORT_OK = (DOCUMENT_ROOT); # But this does not work

1;

use MyConfig qw(DOCUMENT_ROOT);
print DOCUMENT_ROOT;

# If I do not use qw , I will get error of "DOCUMENT_ROOT" is not exported by the MyConfig module
# Why is qw importance is so significance here ?
# I thought qw is just a syntatic sugar of perl to make a list
# Thank you.

That's correct. qw splits its parameter on whitespace, so

qw(A B C)

is similar to

split ' ', 'A B C'


So if you write

use MyConfig 'DOCUMENT_ROOT';

or

use MyConfig ('DOCUMENT_ROOT');

then your program will work as expected. But because you've defined the constant
DOCUMENT_ROOT to be "/var/www/"

use MyConfig (DOCUMENT_ROOT);

is the same as saying

use MyConfig ("/var/www/");

which is nonsense.

HTH,

Rob



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