例子
do
local tab = {1, 2, 3}
function closure()
for key, value in ipairs(tab) do
print(key, "I can still see you")
end
end
closure()
--> 1 I can still see you
--> 2 I can still see you
--> 3 I can still see you
end
print(tab) --> nil
-- tab is out of scope
closure()
--> 1 I can still see you
--> 2 I can still see you
--> 3 I can still see you
-- the function can still see tab典型用法示例
function new_adder(number)
return function(input)
return input + number
end
end
add_3 = new_adder(3)
print(add_3(2)) --> prints 5更高级的用法示例
function base64.newDecoder(str) -- Decoder factory
if #str ~= 64 then return nil, "string must be 64 characters long!" end
local tab = {}
local counter = 0
for c in str:gmatch"." do
tab[string.byte(c)] = counter
counter = counter + 1
end
return function(str)
local result = ""
for abcd in str:gmatch"..?.?.?" do
local a, b, c, d = string.byte(abcd,1,-1)
a, b, c, d = tab[a], tab[b] or 0, tab[c] or 0, tab[d] or 0
result = result .. (
string.char( ((a<<2)+(b>>4))%256 ) ..
string.char( ((b<<4)+(c>>2))%256 ) ..
string.char( ((c<<6)+d)%256 )
)
end
return result
end
end
