use constant {
    zed=>0,
    one=>1,
    two=>2,
};
use constant repos=>(qw(oss non-oss debug)); # NOTE to future self: cannot be in the `use constant { ... }`:
    # because an array cannot be the value for a key in an anonymous hash; 
    # to create a constant array, it has to be in a separate `use constant` line; 
    # do not try to optimize this back into the `use constant {...}` because it won't work!  
    # Really, I mean it!