Just thought I'd share this gotcha I encountered while trying to use Getopt::Declare. [This is not specific to G::D, but occurs with any module taking variable parameters.] 
#!/your/perl/here
use strict;
use warnings;

my $options;
my $string;

BEGIN 
{
    $string = <<'HERE';

    -one <one:i>    First parameter
    
HERE
}

use Getopt::Declare $string => $options;   ### <<< BONK!

print "one = $options->{-one}\n";

[download]
To use this form of G::D, $string and $options must exist (such as with my), and $string must be defined, such as through a BEGIN (before the compiler sees use Getopt::Declare).

To avoid this, at least with G::D, use the following instead: 

use Getopt::Declare;
$options = Getopt::Declare->new($string);

[download]
You can use a banana to drive a nail, but you'll need to precondition the nail, or the banana, or both.

-QM
--
Quantum Mechanics: The dreams stuff is made of

In reply to use module with parameter variable by QM

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.