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13.3.2 Characters

Remember that CMUCL’s characters are only 16-bits long but Unicode codepoints are up to 21 bits long. Hence there are codepoints that cannot be represented via Lisp characters. Operating on individual characters is not recommended. Operations on strings are better. (This would be true even if CMUCL’s characters could hold a full Unicode codepoint.)

Function: char-equal &rest characters ¶

Function: char-not-equal &rest characters ¶

Function: char-lessp &rest characters ¶

Function: char-greaterp &rest characters ¶

Function: char-not-greaterp &rest characters ¶

Function: char-not-lessp &rest characters ¶

For the comparison, the characters are converted to lowercase and the corresponding char-code are compared.

Function: alpha-char-p character ¶

Returns non-nil if the Unicode category is a letter category.

Function: alphanumericp character ¶

Returns non-nil if the Unicode category is a letter category or an ASCII digit.

Function: digit-char-p character &optional radix ¶

Only recognizes ASCII digits (and ASCII letters if the radix is larger than 10).

Function: graphic-char-p character ¶

Returns non-nil if the Unicode category is a graphic category.

Function: upper-case-p character ¶

Function: lower-case-p character ¶

Returns non-nil if the Unicode category is an uppercase (lowercase) character.

Function: lisp:title-case-p character ¶

Returns non-nil if the Unicode category is a titlecase character.

Function: both-case-p character ¶

Returns non-nil if the Unicode category is an uppercase, lowercase, or titlecase character.

Function: char-upcase character ¶

Function: char-downcase character ¶

The Unicode uppercase (lowercase) letter is returned.

Function: lisp:char-titlecase character ¶

The Unicode titlecase letter is returned.

Function: char-name char ¶

If possible the name of the character char is returned. If there is a Unicode name, the Unicode name is returned, except spaces are converted to underscores and the string is capitalized via string-capitalize. If there is no Unicode name, the form #\U+xxxx is returned where “xxxx” is the char-code of the character, in hexadecimal.

Function: name-char name ¶

The inverse to char-name. If no character has the name name, then nil is returned. Unicode names are not case-sensitive, and spaces and underscores are optional.