S9 LIB  (string-find string1 string2)          ==>  string | #f
        (string-ci-find string1 string2)       ==>  string | #f
        (string-find-word string1 string2)     ==>  string | #f
        (string-ci-find-word string1 string2)  ==>  string | #f

        (load-from-library "string-find.scm")

Find the first occurrence of a small string STRING1 in a large
string STRING2. Return the first substring of STRING2 beginning
with STRING1. When STRING2 does not contain STRING1, return #F.
STRING-CI-FIND performs the same function, but ignores case.

STRING-FIND-WORD (STRING-CI-FIND-WORD) differs from STRING-FIND
(STRING-CI-FIND) in that is matches only full words, where a full
word is a subsequence of characters that is delimited on both
sides by one of the following:

        - the beginning of the string;
        - the end of the string;
        - a non-alphabetic character.

(string-find "ein" "gemeinsam")     ==>  "einsam"
(string-find "people" "democracy")  ==>  #f
(string-find-word "me" "test me")   ==>  "me"
(string-find-word "me" "testme")    ==>  #f
