When you’re programatically creating an abstract syntax tree in order to generate a text representation of a regular expression in order to parse it into an abstract syntax stree in order to compile it to a matcher object which reads your sequential list in a random access manner (causing you to have to fake random access behaviour with a mutable index into your list) in order to iterate over it sequentially…

…at this point the idea that someone, somewhere, might be doing something wrong starts to sink in.