code: function logRead(from, to) {
      var fromslot, toslot = to.source1 === null ? -1 : to.sources === null ? 0 : to.sources.length;
      if (from.node1 === null) {
          from.node1 = to;
          from.node1slot = toslot;
          fromslot = -1;
      }
      else if (from.nodes === null) {
          from.nodes = [to];
          from.nodeslots = [toslot];
          fromslot = 0;
      }
      else {
          fromslot = from.nodes.length;
          from.nodes.push(to);
          from.nodeslots.push(toslot);
      }
      if (to.source1 === null) {
          to.source1 = from;
          to.source1slot = fromslot;
      }
      else if (to.sources === null) {
          to.sources = [from];
          to.sourceslots = [fromslot];
      }
      else {
          to.sources.push(from);
          to.sourceslots.push(fromslot);
      }
  }
docs: Functions