Simple chessboard app. Nothing funky, just putting wart through its paces. (Compare with python version at http://gist.github.com/1218667)

090chessboard.wart

# Requirements: g++
# $ git clone http://github.com/akkartik/wart.git
# $ cd wart
# $ git checkout b5fb9cbccb
# $ wget --no-check-certificate https://raw.github.com/gist/1291243/080chessboard.wart
# $ wart
# Use the 'm' function to make a move. P-K4 is m.5254, etc. m.-1 is undo.

# type chessboard
# Uppercase is white, lowercase is black
<- Board (tag 'chessboard '((r n b q k b n r)
                            (p p p p p p p p)
                            (_ _ _ _ _ _ _ _)
                            (_ _ _ _ _ _ _ _)
                            (_ _ _ _ _ _ _ _)
                            (_ _ _ _ _ _ _ _)
                            (P P P P P P P P)
                            (R N B Q K B N R)))

# print chessboard objects
def (pr x) :case (isa chessboard x)
  let board rep.x
    each row board
      each square row
        pr square
        pr " "
      prn ""

# setup indexing for objects of type chessboard: board.row.col
defcall chessboard (board n)
  rep.board.n

# each move consists of from-square to-square piece-captured
<- Moves nil

# make a move. P-K4 is m.5254, etc.
proc (m n)
  <- r2 (8 - n%10)  n n/10
  <- c2 (n%10 - 1)  n n/10
  <- r1 (8 - n%10)  n n/10
  <- c1 n-1
  push (list r1 c1 r2 c2 Board.r2.c2) Moves
  Board.r2.c2 <- Board.r1.c1
  Board.r1.c1 <- '_

# undo
proc (m n) :case (n = -1)
  let (r1 c1 r2 c2 old_piece) car.Moves
    Board.r1.c1 <- Board.r2.c2
    Board.r2.c2 <- old_piece
    zap cdr Moves

after_calling (m n)
  prn Board

prn Board

runlog.txt

$ wart
r n b q k b n r 
p p p p p p p p 
_ _ _ _ _ _ _ _ 
_ _ _ _ _ _ _ _ 
_ _ _ _ _ _ _ _ 
_ _ _ _ _ _ _ _ 
P P P P P P P P 
R N B Q K B N R 

wart> m.5254

r n b q k b n r 
p p p p p p p p 
_ _ _ _ _ _ _ _ 
_ _ _ _ _ _ _ _ 
_ _ _ _ P _ _ _ 
_ _ _ _ _ _ _ _ 
P P P P _ P P P 
R N B Q K B N R 

nil
wart> m.5755

r n b q k b n r 
p p p p _ p p p 
_ _ _ _ _ _ _ _ 
_ _ _ _ p _ _ _ 
_ _ _ _ P _ _ _ 
_ _ _ _ _ _ _ _ 
P P P P _ P P P 
R N B Q K B N R 

nil
wart> m.-1

r n b q k b n r 
p p p p p p p p 
_ _ _ _ _ _ _ _ 
_ _ _ _ _ _ _ _ 
_ _ _ _ P _ _ _ 
_ _ _ _ _ _ _ _ 
P P P P _ P P P 
R N B Q K B N R 

nil
wart> m.3735

r n b q k b n r 
p p _ p p p p p 
_ _ _ _ _ _ _ _ 
_ _ p _ _ _ _ _ 
_ _ _ _ P _ _ _ 
_ _ _ _ _ _ _ _ 
P P P P _ P P P 
R N B Q K B N R 

nil
wart>