String<= is a Common Lisp function. See any Common Lisp
documentation for more information.
Major Section: PROGRAMMING
(String<= str1 str2) is non-nil if and only if the string
str1 precedes the string str2 lexicographically or the strings
are equal. When non-nil, (string<= str1 str2) is the first
position (zero-based) at which the strings differ, if they differ,
and otherwise is their common length. See string<.
The guard for string<= specifies that its arguments are strings.
String<= is a Common Lisp function. See any Common Lisp
documentation for more information.