The LISP interpreter first does a lexical analysis of all input and splits up
the input into delimiters and atoms, while discarding whitespace:
In many LISPs atoms that are not strings or numbers are converted to upper case. In other LISPs the same atoms are converted to lower case.
The dot (a period) separated from an atom or number is use to idicate the fundamental data structure in LISP of the dotted pair: "( FIRST . SECOND)".