Numeric literals are specified in any of the usual  floating
     point or integer formats:

         12345
         12345.67
         .23E-10
         0xffff     # hex
         0377  # octal

     String literals are delimited by  either  single  or  double
     quotes.   They  work  much like shell quotes:  double-quoted
     string literals are subject to backslash and  variable  sub-
     stitution;  single-quoted strings are not (except for \' and
     \\).  The usual backslash rules apply for making  characters
     such  as  newline,  tab,  etc.,  as well as some more exotic
     forms:

          \t        tab
          \n        newline
          \r        return
          \f        form feed
          \b        backspace
          \a        alarm (bell)
          \e        escape
          \033      octal char
          \x1b      hex char
          \c[       control char
          \l        lowercase next char
          \u        uppercase next char
          \L        lowercase till \E
          \U        uppercase till \E
          \E        end case modification