fountainedge

// @link https://stackoverflow.com/questions/57222372/how-to-get-rank-of-nodes-after-processing-with-graphviz-dot
// dot -Tdot test1.dot | gvpr -f rank.gvpr
BEGIN {
  int i, j, N, R=0,  nIndx=0, list[string];
  string rankList[double];
  string nodeIndx[int];
  string str1, RankDir="TB"; 
  node_t aNode, thisNode[];
  double dist;

  void setRank(){
    R++;
    str1=substr(rankList[dist],1);     // strip leading delimiter
    unset(nodeIndx);                      // delete array of node indices
    N=split(str1, nodeIndx, "|");
    for (i=0; i<N; i++){              // for each node in this rank (w/ same Y/X pos)
      j=nodeIndx[i];
      aNode=thisNode[j];
      print (aNode.name, " ", aNode.id, " ", R);
    }
  }
}
BEG_G{
  if (hasAttr($G, "rankdir") && $G.rankdir!="")
    RankDir=$G.rankdir;
}
N {
  thisNode[++nIndx]=$;  // index the nodes
  if (RankDir=="LR|RL"){        // ksh pattern matching
    dist=$.X;
  } else {
    dist=$.Y;
  }
  // build a string containing all node indices, based on (indexed by) Y/X value
  rankList[dist]=sprintf("%s|%s", rankList[dist], nIndx);
}
END_G{
  // for each rank, in sorted order
  if (RankDir=="TB|RL"){        //      ksh pattern matching
    forr (rankList[dist]){      //  decreasing sort
      setRank();
    }
  }else{
    for (rankList[dist]){       // increasing sort
      setRank();
    }
  }
}