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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.

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

Figure 13.1: Character defined names – 1

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

char-code char-name code-char
char-downcase char-upcase digit-char
char-int character name-char

Figure 13.2: Character defined names – 2