</span>
        (string-set! buf idx (string-ref s1 idx))
        (string-append-2 s1 s2 buf (1+ idx)))))
(<span class="keyword">define</span> (<span class="function-name">string-append</span> s1 s2)       <span class="comment">; standard
</span>  (string-append-2 s1 s2 (make-string (+ (string-length s1)
                                         (string-length s2)))
                   0))
</pre></blockquote>

<p>That horrible rat's nest is my attempt to straightforwardly
translate this very straightforward p