Mini Shell

/* Report if graph has non-hierarchical clusters */
BEGIN {
  graph_t c[node_t];
  node_t n;

  void proc (graph_t h, graph_t p, graph_t g)
  {
    if (h.name == "cluster*") {
      for (n = fstnode(h); n; n = nxtnode_sg(h,n)) {
		g = c[n];
		if (g) {
		  if (g != p) {
            printf(2,"node %s in %s and %s\n", n.name, h.name, g.name);
		    exit(1);
          }
        }
        c[n] = h;
      }
      p = h;
    }
    for (g = fstsubg(h); g; g = nxtsubg(g)) {
      proc(g,p,NULL);
    }
  }
}
BEG_G {
  proc($,$,NULL);
}