Scala comes with a concept of symbols - strings that are interned, that is: two symbols with the same name (the same character sequence), in contrary to strings, will refer to the same object during execution.
Symbols are a feature of many languages: Lisp, Ruby and Erlang and more, however in Scala they are of relatively small use. Good feature to have nevertheless.
Any literal beginning with a single quote
', followed by one or more digits, letters, or under‐scores
_ is a symbol literal. The first character is an exception as it can’t be a digit.
'ATM 'IPv4 'IPv6 'map_to_operations 'data_format_2006 // Using the `Symbol.apply` method Symbol("hakuna matata") Symbol("To be or not to be that is a question")
'8'th_division '94_pattern 'bad-format