I have a set of constants declared in Perl:
use constant C1 => 111;
use constant C2 => 222;
..
use constant C9 => 999;
my $which_constant = "C2";
How do I construct a Perl expression which, based on $which_constant
, derives the value of a constant named with the value of this variable - e.g. "222".
Please note that I can not change any of the conditions above - they are a simplification of a real scenario: I have a module (which I have no control over) from which these constants are imported. The `name of one of the constants is supplied by the user from command line. I need to access the appropriate constants' value.
I've been beating my head against the wall (mostly around all sorts of weird glob constructs) but none of them work.
P.S. If the solution accesses the constants inside their native module - say My::Constants::C2
(without needing to import them), even better, but not necessary - I can import the correct constants into main::
easily using My::Constants->import($which_constant)
. and yes, to top it off, te constants are NOT exported by default thus needing the explicit import() call.
Some of the things I tried:
main::$which_constant
- syntax errormain::${which_constant}
- syntax error${*$which_constant}
- returns empty value*$which_constant
- returns "*main::C2"${*${*which_constant}}
- empty