yep I just deciphered it from the error msg.

update

> do you know why is this happening?

the initialization of @aminos is never executed.

using strict and warnings might have shown you.

either put the initialization into the sub or declare a constant (string please!).

update

darn, constants are not interpolated in strings or regexes.

you have to define a constant regex:

  DB<131> use constant REGEX=>qr/[^ABCD]/

  DB<132> 'C' =~ REGEX

  DB<133> 'Z' =~ REGEX
 => 1
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darn, constants are not interpolated in strings or regexes.

As I understand it, even with use constant, a constant in Perl is an in line sub. IE:

use constant PI    => 4 * atan2(1, 1);
[download]

is the short hand for

sub PI
{
    4 * atan2(1, 1);
}
[download]

Which, after compile time constant expression evaluation, simplifies to:

sub PI
{
    3.1415926536; # to the precision available on the machine running 
+the program
}
[download]

which the compiler can then in line where it would otherwise put a sub call.

> where it would otherwise put a sub call.

which isn't trivial within strings/regexes.

the "@{[...]}" trick works but is IMHO a bit oversized for this task.

  DB<109> use constant STR => 1..3

  DB<110> qr/[@{[ STR ]}]/
 => qr/[1 2 3]/
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thats not interpolation anymore but inline eval.

Cheers Rolf

( addicted to the Perl Programming Language)

As mentioned before, you're invoking the subroutine (it's invoked during  GetOptions() processing) before the array is initialized. Eg.:

c:\@Work\Perl\monks>perl -wMstrict -le
"S('before');
 ;;
 my @ra = qw(A C T G);
 ;;
 S('after');
 ;;
 sub S { print qq{$_[0] initialization: [@ra] }; }
"
before initialization: []
after initialization: [A C T G]
[download]