char-name character → name

character — a character.

name — a string or nil.

Returns a string that is the name of the character, or nil if the character has no name.

All non-graphic characters are required to have names unless they have some implementation-defined attribute which is not null. Whether or not other characters have names is implementation-dependent.

The standard characters ⟨Newline⟩ and ⟨Space⟩ have the respective names "Newline" and "Space". The semi-standard characters ⟨Tab⟩, ⟨Page⟩, ⟨Rubout⟩, ⟨Linefeed⟩, ⟨Return⟩, and ⟨Backspace⟩ (if they are supported by the implementation) have the respective names "Tab", "Page", "Rubout", "Linefeed", "Return", and "Backspace" (in the indicated case, even though name lookup by “#\” and by the function name-char is not case sensitive).

 (char-name #\ ) → "Space" 
 (char-name #\Space) → "Space" 
 (char-name #\Page) → "Page" 

 (char-name #\a) 
→ NIL 
or → "LOWERCASE-a" 
or → "Small-A" 
or → "LA01" 

 (char-name #\A) 
→ NIL 
or → "UPPERCASE-A" 
or → "Capital-A" 
or → "LA02" 

 ;; Even though its CHAR-NAME can vary, #\A prints as #\A 
 (prin1-to-string (read-from-string (format nil "#\\~A" (or (char-name #\A) "A")))) 
→ "#\\A"

Should signal an error of type type-error if character is not a character.

name-char, Section 22.1.3.2 (Printing Characters)

Non-graphic characters having names are written by the Lisp printer as “#\” followed by the their name; see Section 22.1.3.2 (Printing Characters).