If you have been led to believe that associative arrays in perl
don't preserve order, and if you have ever craved for that feature,
this module is for you.  Simply declare a "tie" for the hash variable
that you want to be order-preserving, and forget that limitation
ever existed.  You can do other nifty things with the tied hash object
that you may be used to doing with arrays, like Push(), Pop() and
Splice().

Homepage:
https://metacpan.org/release/Tie-IxHash
