In addition to juster's Re: Overwriting a Constant, probably the closest you can get is via simulative (re)setting of constants from the command line by using Getopt::constant, you provide default values - for constants you use (these values can be scalars, lists or even coderefs) - upon 'use'ing Getopt::constant, then from the command line these constants can be made to look like having been assigned new values or used in their original definitions.

Interesting to note is that Getopt::constant does prefix such constants too and this serves to distinguish them by providing a label before the constant name, you can pass empty-string to the ':prefix' label too.

#SYNOPSIS from Getopt::constant document...
# Assuming @ARGV is: ('-foo=9,8,7', '-bar', 'wakawaka.txt')
  use Getopt::constant (
    ':prefix' => 'C_',   #Can be null too
    'foo' => [3,5],
    'bar' => 0,
    ':usage' =>
  "Usage:
  thingamabob
    -foo=one,two,three  :  fooey on these items
    -bar                :  enable barriness
  ",
  );
  # @ARGV is now 'wakawaka.txt', and you've now got
  #  a constant C_foo with value (9,8,7)
  #  and a constant C_bar with value 1
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N.B: Nefarious purposes can backfire in a hairy way so 'plot' with caution...