我完全困惑于
Lua的变量范围和函数参数传递(值或引用)。
见下面的代码：
local a = 9 -- since it's define local,should not have func scope
local t = {4,6} -- since it's define local,should not have func scope
function moda(a)
a = 10 -- creates a global var?
end
function modt(t)
t[1] = 7 -- create a global var?
t[2] = 8
end
moda(a)
modt(t)
print(a) -- print 9 (function does not modify the parent variable)
print(t[1]..t[2]) -- print 78 (some how modt is modifying the parent t var)
因此，这种行为完全使我困惑。
解决方法
你猜到了，表变量通过引用传递。引用
Lua 5.1 Reference Manual：
There are eight basic types in Lua: nil,boolean,number,string,function,userdata,thread,and table.
….Tables,functions,threads,and (full) userdata values are objects: variables do not actually contain these values,only references to them. Assignment,parameter passing,and function returns always manipulate references to such values; these operations do not imply any kind of copy.
所以nil，布尔，数字和字符串通过值。这正好解释了你观察的行为。