Package xstrings provides addons to standard package strings.
HeadTail splits string into head & tail.
(head+sep+tail) -> head, tail.
Note: tail may contain sep.
Split2 splits string by sep and expects exactly 2 parts.
SplitLines splits string into lines.
The last line, if it is empty, is omitted from the result. (rationale is: string.Split("hello\nworld\n", "\n") -> ["hello", "world", ""])