docs: function tighten(statements) {
                  var cur, prev;
                  for (var i = 0, ret1 = []; i < statements.length; ++i) {
                          cur = statements[i];
                          if (cur[0] == "block") {
                                  if (cur[1]) {
                                          ret1.push.apply(ret1, cur[1]);
                                  }
                          } else {
                                  ret1.push(cur);
                          }
                  }
                  prev = null;
                  for (var i = 0, ret2 = []; i < ret1.length; ++i) {
                          cur = ret1[i];
                          if (prev && ((cur[0] == "var" && prev[0] == "var") ||
                                       (cur[0] == "const" && prev[0] == "const"))) {
                                  prev[1] = prev[1].concat(cur[1]);
                          } else {
                                  ret2.push(cur);
                                  prev = cur;
                          }
                  }
                  if (!options.make_seqs)
                          return ret2;
                  prev = null;
                  for (var i = 0, ret3 = []; i < ret2.length; ++i) {
                          cur = ret2[i];
                          if (!prev) {
                                  if (cur[0] == "stat") {
                                          prev = [ "seq", cur[1] ];
                                          ret3.push([ "stat", prev ]);
                                  } else {
                                          ret3.push(cur);
                                  }
                          } else if (cur[0] == "stat") {
                                  prev.push(cur[1]);
                          } else if (cur[0] == "seq") {
                                  prev.push.apply(prev, slice(cur, 1));
                          } else {
                                  prev = null;
                                  ret3.push(cur);
                          }
                  }
                  return ret3.map(walk);
          }