This rockstar program turns all lower case letters of your input into upper case letters.
It is proof that I am indeed a "Rockstar developer".
or compile/transpile/interpret the code with one of the tools recommended at rockstar implementations.
See the the minimalist version explaining the program. The idiomatic version just uses other variable names and some command aliases.
This program builds a mapping table for all lower case characters and their respective upper case characters. It then checks for every element of the input if a mapping could be found and if so, it uses this mapping value in the output.
See all rockstar language features in the docs.