Some functions, for certain arguments/values, will convert basic types (number, duration, date-time, regex) to strings. This does not include lists, hashes, or Booleans.
Regex functions (for the string to match), such as match() and replace(), as well as regex used with the forward operator, use
The functions that write to standard out or standard error (write(), writeln(), writeErr(), writelnErr()) use full
Auto-stringification does not apply to return values. It only applies to arguments.
The join() function uses
join series(1..7), by="|" # result: "1|2|3|4|5|6|7"