Data commit

Task/Generate-random-chess-position/Zkl/generate-random-chess-position-1.zkl

@@ -0,0 +1,38 @@
+fcn pickFEN{
+   # First we chose how many pieces to place: 2 to 32
+   n := (0).random(2,33);
+
+   # Then we pick $n squares: first n of shuffle (0,1,2,3...63)
+   n = [0..63].walk().shuffle()[0,n];
+
+   # We try to find suitable king positions on non-adjacent squares.
+   # If we could not find any, we return recursively
+   kings := Walker.cproduct(n,n).filter1(fcn([(a,b)]){  // Cartesian product
+      a!=b and (a/8 - b/8).abs() or (a%8 - b%8).abs()>1
+   }); # (a,b) on success, False on fail
+   if(not kings) return(pickFEN());    // tail recursion
+
+   # We make a list of pieces we can pick (apart from the kings)
+   pieces,pnp,pnP := "p P n N b B r R q Q".split(" "), pieces-"p", pieces-"P";
+
+   # We make a list of two king symbols to pick randomly a black or white king
+   k := "K k".split(" ").shuffle();
+
+   [0..63].apply('wrap(sq){  # look at each square
+      if(kings.holds(sq)) k.pop();
+      else if(n.holds(sq)){
+         row,n,n2 := 7 - sq/8, (0).random(pieces.len()), (0).random(pnp.len());
+	 if(     row == 7) pnP[n2]  // no white pawn in the promotion square
+	 else if(row == 0) pnp[n2]  // no black pawn in the promotion square
+	 else 		   pieces[n] // otherwise, any ole random piece
+      }
+      else "#"  // empty square
+   })
+   .pump(List,T(Void.Read,7),"".append,subst)  // chunkize into groups of 8 chars (1 row)
+   .concat("/") + " w - - 0 1"
+}
+fcn subst(str){  // replace "#" with count of #s
+   re :=RegExp("#+");
+   while(re.search(str,1)){ n,m:=re.matched[0]; str=String(str[0,n],m,str[n+m,*]) }
+   str
+}

Task/Generate-random-chess-position/Zkl/generate-random-chess-position-2.zkl

@@ -0,0 +1 @@
+do(5){ pickFEN().println() }