8 Queens in Forth

I am sure you always wanted to know what a solution to the eight queens puzzle would look like in Forth.

create board 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,

: display-row ( r -- )
  { r }
  48 r + emit
  8 0 do
    124 emit	
    board i cells + @ r = if
      42 emit
    else
      32 emit
    endif	
  loop
  124 emit
  cr ;

: display
  cr
  8 0 do
    i display-row
  loop ;

: is-conflict
  { c }
  c 0 ?do
    board i cells + @ board c cells + @ =
    board i cells + @ i + board c cells + @ c + = or
    board i cells + @ i - board c cells + @ c - = or if
      true unloop exit
    endif
  loop
  false ;

create col 0 ,

: solve
  { max }
  0 >r
  0 begin
    board col @ cells + @ 7 > if
      0 board col @ cells + ! 
      col @ 0 = if exit endif
      col @ 1 - col !
      board col @ cells + @ 1 + board col @ cells + !
    else
      col @ is-conflict false = if
        col @ 7 = if
          display
          r> 1 + >r
          r@ max >= if rdrop exit endif
        endif
        col @ 1 + col !
      else
        board col @ cells + @ 1 + board col @ cells + !
      endif
    endif
  again ;