string-upcase

(string-upcase string-designator)

Returns a new string with every lowercase letter converted to uppercase; the original string is unchanged. The argument is a string designator, so a symbol, a keyword or a character is also accepted -- a symbol's name is used and a keyword's leading colon is dropped, so (string-upcase :foo) returns "FOO" and (string-upcase #\a) returns "A". Anything that is not one of those three types is an error. Case conversion is full-Unicode and identical on every backend: each character is folded with char-upcase, so (string-upcase "éλω") returns "ÉΛΩ". Because the fold is per character, the result always has the same length as the argument -- there is no multi-character special casing ((string-upcase "straße") returns "STRAßE", not "STRASSE").