How can I get coordinates working in this code?

Question

I am about to start writing a chess program using Tkinter/ Python and I am experimenting with coordinates for moves as I have never used them before. How can I get this code working as right now I get: NameError: name 'x' is not defined.Thanks in advance for the help.

movelist=[]
KNIGHTLIST=[(x+2,y+1),(x+2,y-1),(x-2,y+1),(x-2,y-1),(x+1,y+2),(x+1,y-2),(x-1,y+2),(x-1,y-2)]
index=0
pieceposition=(3,4)
newposition=(0,0)
for move in KNIGHTLIST:
    newposition=pieceposition+KNIGHTLIST[index] 

    movelist.append(newposition)
    index=index+1
print (movelist)

Answer 1

You need to add the proper offset to the current piece position, and return the list of possible legal positions.

maybe something along these lines:

def get_possible_knight_moves(pos):
    x, y = pos
    possible_moves = []
    for dx, dy in knight_offsets:
        new_pos = (x + dx, y + dy)
        if is_legal(new_pos):
            possible_moves.append(new_pos)
    return possible_moves

def is_legal(pos):
    x, y = pos
    return 0 <= x < 8 and 0 <= y < 8


knight_offsets = [(2, 1), (2, -1), (1, 2), (1, -2), (-2, 1), (-2, -1),(-1, 2),(-1, -2)]

pieceposition = (3 , 4)
movelist = get_possible_knight_moves(pieceposition)
print (movelist)

output:

[(5, 5), (5, 3), (4, 6), (4, 2), (1, 5), (1, 3), (2, 6), (2, 2)]

For a knight in position (0, 0) , the output is [(2, 1), (1, 2)]