Specific hints:

1. Super Search for "dispatch table"
2. See uc and split
3. Use modules, such as (for just one sweeping example) Date::Calc

General hint:

Questions that merely ask the monks to do your work for you, without showing any effort, are unlikely to get the help requested. Try reading the documentation, tutorials, FAQS, and other info available to you and try writing some code. Then come back and ask -- with your code as part of the post -- specific questions related to specific problems.

Update: fixed formatting, clarified.