RosettaCodeData/Task/Maze-generation/Rascal/maze-generation.rascal

import IO;
import util::Math;
import List;

public void make_maze(int w, int h){
   vis = [[0 | _ <- [1..w]] | _ <- [1..h]];
   ver = [["|  "| _ <- [1..w]] + ["|"] | _ <- [1..h]] + [[]];
   hor = [["+--"| _ <- [1..w]] + ["+"] | _ <- [1..h + 1]];

   void walk(int x, int y){
      vis[y][x] = 1;

      d = [<x - 1, y>, <x, y + 1>, <x + 1, y>, <x, y - 1>];
      while (d != []){
         <<xx, yy>, d> = takeOneFrom(d);
         if (xx < 0 || yy < 0 || xx >= w || yy >= w) continue;
         if (vis[yy][xx] == 1) continue;
         if (xx == x) hor[max([y, yy])][x] = "+  ";
         if (yy == y) ver[y][max([x, xx])] = "   ";
         walk(xx, yy);
         }
   }

   walk(arbInt(w), arbInt(h));
   for (<a, b> <- zip(hor, ver)){
      println(("" | it + "<z>" | z <- a));
      println(("" | it + "<z>" | z <- b));
   }
}