The delimiter can be from zero to 16 characters long and may contain any member of the basic source character set except whitespace characters, parentheses, or backslash.
After seeing the backslash, the compiler expects another character to complete the escape sequence, and then translates the escape sequence into the character it is intended to represent.
Most frequently, ending a line with a backslash (immediately followed by a newline) results in the line being "continued" the following line is "joined" to the previous line.
A quoted string can typically contain anything but a quote, while an unquoted identifier atom can typically contain anything but quote, whitespace characters, parenthesis, brackets, braces, backslash, and semicolon.