我目前正在阅读《Lua 编程》第四版，并且已经陷入了“第 2 章插曲：八皇后谜题”的第一个练习。
示例代码如下：
N = 8 -- board size
-- check whether position (n, c) is free from attacks
function isplaceok (a, n ,c)
for i = 1, n - 1 do -- for each queen already placed
if (a[i] == c) or -- same column?
(a[i] - i == c - n) or -- same diagonal?
(a[i] + i == c + n) then -- same diagonal?
return false -- place can be attacked
end …