function make_getter_setter(id, should_splitjoin) {

     return function (maybe_newval) {

         var elt = document.getElementById(id);

         if (maybe_newval) {

             elt.value = should_splitjoin ? maybe_newval.join(" ") : maybe_newval;

             return undefined;

         } else {

             return should_splitjoin ? elt.value.split(/ +/) : elt.value;

         }

     };

 }

 var f0 = make_getter_setter("f0", true);

 var f1 = make_getter_setter("f1", true);

 var f2 = make_getter_setter("f2", true);

 var f3 = make_getter_setter("f3", false);

 function demo_lcs() {

     f3(uneval(Diff.longest_common_subsequence(f1(), f2())));

 }

 function demo_comm() {

     f3(uneval(Diff.diff_comm(f1(), f2())));

 }

 function demo_diff_patch() {

     f3(uneval(Diff.diff_patch(f1(), f2())));

 }

 function demo_invert() {

     p = eval(f3());

     Diff.invert_patch(p);

     f3(uneval(p));

 }

 function demo_apply_patch() {

     f2(Diff.patch(f1(), eval(f3())));

 }

 function demo_diff1() {

     f3(uneval(Diff.diff_patch(f0(), f1())));

 }

 function demo_diff2() {

     f3(uneval(Diff.diff_patch(f0(), f2())));

 }

 function demo_diff3(excludeFalseConflicts) {

     f3(uneval(Diff.diff3_merge(f1(), f0(), f2(), excludeFalseConflicts)));

 }

 function demo_diff3_cooked(excludeFalseConflicts) {

     var merger = Diff.diff3_merge(f1(), f0(), f2(), excludeFalseConflicts);

     var lines = [];

     for (var i = 0; i < merger.length; i++) {

         var item = merger[i];

         if (item.ok) {

             lines = lines.concat(item.ok);

         } else {

             lines = lines.concat(["\n<<<<<<<<<\n"], item.conflict.a,

                                  ["\n=========\n"], item.conflict.b,

                                  ["\n>>>>>>>>>\n"]);

         }

     }

     f3(lines.join(" "));

 }

 function demo_diff3_dig_in() {

     var merger = Diff.diff3_merge(f1(), f0(), f2(), false);

     var lines = [];

     for (var i = 0; i < merger.length; i++) {

         var item = merger[i];

         if (item.ok) {

             lines = lines.concat(item.ok);

         } else {

             var c = Diff.diff_comm(item.conflict.a, item.conflict.b);

             for (var j = 0; j < c.length; j++) {

                 var inner = c[j];

                 if (inner.common) {

                     lines = lines.concat(inner.common);

                 } else {

                     lines = lines.concat(["\n<<<<<<<<<\n"], inner.file1,

                                          ["\n=========\n"], inner.file2,

                                          ["\n>>>>>>>>>\n"]);

                 }

             }

         }

     }

     f3(lines.join(" "));

 }