2.2 Whitespace and comments
Whitespace characters are spaces and newlines.
(Implementations typically provide additional whitespace characters such
as tab or page break.) Whitespace is used for improved readability and
as necessary to separate tokens from each other, a token being an
indivisible lexical unit such as an identifier or number, but is
otherwise insignificant. Whitespace may occur between any two tokens,
but not within a token. Whitespace may also occur inside a string,
where it is significant.
A semicolon (;) indicates the start of a
comment. The comment continues to the
end of the line on which the semicolon appears. Comments are invisible
to Scheme, but the end of the line is visible as whitespace. This
prevents a comment from appearing in the middle of an identifier or
;;; The FACT procedure computes the factorial
;;; of a non-negative integer.
(if (= n 0)
1 ;Base case: return 1
(* n (fact (- n 1))))))