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standard-char

standard-char Type

Supertypes:

standard-char, base-char, character, t

Description:

A fixed set of 96 characters required to be present in all conforming implementations. Standard characters are defined in Section 2.1.3 (Standard Characters).

Any character that is not simple is not a standard character .

See Also:

Section 2.1.3 (Standard Characters)

Expanded Reference: standard-char​

The standard-char type​

standard-char is a type comprising exactly 96 characters that must be present in every conforming Common Lisp implementation: 26 uppercase letters, 26 lowercase letters, 10 digits, the space, newline, and a set of punctuation characters.

(typep #\A 'standard-char)
=> T
(typep #\a 'standard-char)
=> T
(typep #\0 'standard-char)
=> T
(typep #\Space 'standard-char)
=> T
(typep #\Newline 'standard-char)
=> T

Type hierarchy​

standard-char is a subtype of base-char, which is a subtype of character.

(subtypep 'standard-char 'base-char)
=> T
=> T
(subtypep 'standard-char 'character)
=> T
=> T

Standard punctuation characters​

The standard character set includes these special characters: !, ", #, $, %, &, ', (, ), *, +, ,, -, ., /, :, ;, <, =, >, ?, @, [, \, ], ^, _, `, {, |, }, ~.

(typep #\! 'standard-char)
=> T
(typep #\@ 'standard-char)
=> T
(typep #\~ 'standard-char)
=> T
(typep #\( 'standard-char)
=> T
(typep #\} 'standard-char)
=> T

Non-standard characters​

Semi-standard characters like Tab and Return are not members of the standard-char type.

(typep #\Tab 'standard-char)
=> NIL
(typep #\Return 'standard-char)
=> NIL

Counting the 96 standard characters​

(count-if (lambda (ch) (typep ch 'standard-char))
          (loop for code from 0 below char-code-limit
                for ch = (code-char code)
                when ch collect ch))
=> 96