string< string> string<= string>= string/= string-lessp string-greaterp string-not-greaterp string-not-lessp string-not-equal

(string< string1 string2 &key start1 end1 start2 end2) -- (string> ...) -- (string<= ...) -- (string>= ...) -- (string/= ...) -- (string-lessp ...) -- (string-greaterp ...) -- (string-not-greaterp ...) -- (string-not-lessp ...) -- (string-not-equal ...)

Compare two strings lexicographically and return the mismatch index (a true value) when the relation holds, nil otherwise. The index is the position in string1 of the first differing character; when the compared substrings are equal it is end1, which is what string<= / string>= / string-not-greaterp / string-not-lessp return for equal strings. The first five are case-sensitive; string-lessp, string-greaterp, string-not-greaterp, string-not-lessp and string-not-equal are the case-insensitive counterparts of string<, string>, string<=, string>= and string/=. Each argument is coerced with string, so a symbol or character designator is accepted and anything else is an error. :start1/:end1/:start2/:end2 bound the substrings actually compared, and the returned index stays absolute in string1.