README: library "Sexplib"
Whitespace, which consists of space, newline, carriage return, horizontal
-tab and form feed, is ignored unless within an OCaml-string, where it is
-treated according to OCaml-conventions. The semicolon introduces comments.
-Comments are ignored, and range up to the next newline character. The left
-parenthesis opens a new list, the right parenthesis closes it again. Lists can
-be empty. The double quote denotes the beginning and end of a string following
-the lexical conventions of OCaml (see OCaml-manual for details). All
-characters other than double quotes, left- and right parentheses, and
-whitespace are considered part of a contiguous string.
+tab, and form feed, is ignored unless within an OCaml-string, where it is
+treated according to OCaml-conventions. The left parenthesis opens a new list,
+the right one closes it again. Lists can be empty. The double quote denotes
+the beginning and end of a string following the lexical conventions of OCaml
+(see the OCaml-manual for details). All characters other than double quotes,
+left- and right parentheses, whitespace, and comment-introducing characters or
+sequences (see next paragraph) are considered part of a contiguous string.
+ A line comment is introduced using a semicolon, which comments out all text
+up to the end of the next newline character. The sequence '%;' introduces an
+S-expression comment. This means that the next S-expression following this
+two-character sequence will be ignored. Whitespace or other comments between
+this sequence and the subsequent S-expression are ignored.
4.2 Grammar of S-expressions