Common Lisp the Language, 2nd Edition Common Lisp provides a
character data type; objects of this type represent printed
symbols such as letters. In general, characters in Common Lisp
are not true objects; eq cannot be counted upon to operate on
them reliably. In particular, it is possible that the expression
(let ((x z) (y z)) (eq x y)) may be false rather than true, if
the value of z is a character. If two objects are to be compared
for ``identity,'' but either might be a character, then the
predicate eql is probably appropriate. X3J13 voted in March 1989
(CHARACTER-PROPOSAL) to approve the following definitions and
terminology for use in discussing character facilities in Common
Lisp. A character repertoire defines a collection of characters
independent of their specific rendered image or font. (This
corresponds to the mathematical notion of a set, but the term
character set is avoided here because it has been used in the
past to mean both what is here called a repertoire and what is
here called a coded ch