I have always disliked using BEGIN blocks to achieve dynamic module inclusion. As a workaround, the 'do' command has been useful for me, in combination with 'do-included' files to achieve this kind of functionality. It has worked for me, but I've never seen anyone else use this approach, not sure what you can conclude from that.

BENEFITS:

• Since the code calls external files, you can make site-wide changes simply by changing the content of the 'do-included' file. You dont have to re-edit your main scripts.
• Fewer lines of code in your main script file.
• You can make as many different 'modes' as you want without adding new lines of code.

HASSLES:

• You have to put the 'use' statements in the 'do-included' file, not the main script.
• Each time you want to make a new 'mode' you have to create a new 'do-include' file.

foo_main_script.pl

my  $sMode  = 'beta';   ### 'beta' or 'prod'
do"/path/to/scripts/".$sMode."_modules.pl";

### insert script code here
[download]

beta_modules.pl

use lib '/path/to/dev/modules';
use module1;
use module2;
use module3;
[download]

prod_modules.pl

use lib '/path/to/prod/modules';
use module1;
use module2;
use module3;
[download]