fixes #802 (#1010)

Author: martin-henz

xml/chapter3/section3/subsection1.xml

@@ -1441,6 +1441,7 @@ set_to_wow(z2);
       <JAVASCRIPT>function</JAVASCRIPT>
     </SPLITINLINE>
     <SNIPPET EVAL="yes">
+      <NAME>count_pairs</NAME>
       <INDEX><DECLARATION>count_pairs</DECLARATION><FRAGILE/></INDEX> 
       <SCHEME>
 (define (count-pairs x)
@@ -1476,18 +1477,18 @@ function count_pairs(x) {
     <SOLUTION>
       <SNIPPET>
         <NAME>exercise_3_16_solution</NAME>
+	<REQUIRES>count_pairs</REQUIRES>
         <EXAMPLE>exercise_3_16_solution_example</EXAMPLE>
         <SCHEME>
         </SCHEME>
         <JAVASCRIPT>
-const cycle = make_cycle(three_list);
-
 const three_list = list("a", "b", "c");
-
-const one = pair("a", "b");
-const three = pair(one, one);
-const four = pair(three, "c");
-const seven = pair(three, three);
+const one = pair("d", "e");
+const two = pair(one, one);
+const four_list = pair(two, "f");
+const seven_list = pair(two, two);
+const cycle = list("g", "h", "i");
+set_tail(tail(tail(cycle)), cycle);
         </JAVASCRIPT>
       </SNIPPET>
 
@@ -1496,8 +1497,8 @@ const seven = pair(three, three);
 	      <JAVASCRIPT>
 // return 3; return 4; return 7;
 display(count_pairs(three_list));
-display(count_pairs(four));
-display(count_pairs(seven));
+display(count_pairs(four_list));
+display(count_pairs(seven_list));
 
 // never return at all
 display(count_pairs(cycle));