Introduction to Characters

ToC

Allegro CL

ANSI Common Lisp

13 Characters

13.1 Character Concepts

13.1.1 Introduction to Characters

A character is an object that represents a unitary token (e.g., a letter, a special symbol, or a "control character") in an aggregate quantity of text (e.g., a string or a text stream).

Common Lisp allows an implementation to provide support for international language characters as well as characters used in specialized arenas (e.g., mathematics).

The following figures contain lists of defined names applicable to characters.

The next figure lists some defined names relating to character attributes and character predicates.

Character defined names -- 1
alpha-char-p	char-not-equal	char>
alphanumericp	char-not-greaterp	char>=
both-case-p	char-not-lessp	digit-char-p
char-code-limit	char/=	graphic-char-p
char-equal	char<	lower-case-p
char-greaterp	char<=	standard-char-p
char-lessp	char=	upper-case-p

The next figure lists some character construction and conversion defined names.

Character defined names -- 2
char-code	char-name	code-char
char-downcase	char-upcase	digit-char
char-int	character	name-char