const V=4;
dist:=V.pump(List,V.pump(List,Void.copy).copy);  // VxV matrix of Void
foreach i in (V){ dist[i][i] = 0 }     // zero vertexes

/* Graph from the Wikipedia:
   1  2  3  4
 d ----------
1| 0  X -2  X
2| 4  0  3  X
3| X  X  0  2
4| X -1  X  0
*/
dist[0][2]=-2; dist[1][0]=4; dist[1][2]=3; dist[2][3]=2; dist[3][1]=-1;

dist,next:=FloydWarshallWithPathReconstruction(dist);
println("Shortest distance array:"); printM(dist);
println("\nPath array:");        printM(next);
println("\nAll paths:");
foreach u,v in (V,V){
   if(p:=path(next,u,v)) p.println();
}