在 Lua 的特定环境中通过元表设置乘法运算符

Question

local names  = setmetatable({},
{__mul = function(a,b) return a|b end}
)
names={i=0,j=1}
tr=load("return i*j",nil,"t",names)()
print(tr)

它将 tr 打印为 0。预期的答案是 1，因为 0|1 结果为 1。代码哪里错了？

Answer 1

尝试：

local mt_obj = {
   __tostring = function(o) return tostring(o[1]) end,
}
local function get(o)
   if type(o) == "table" then return o[1] else return o end
end
local function new(v)
   return setmetatable({v}, mt_obj)
end
function mt_obj.__mul(a,b)
   return new(get(a)|get(b))
end
local mt_env = {
   __index = function(t,k) return new(t.variables[k]) end,
   __newindex = function(t,k,v) t.variables[k] = v end,
}

local names = {i=0,j=1}
local env = setmetatable({variables = names}, mt_env)
tr=get(load("return i*j*8",nil,"t",env)())
print(tr)

在 Lua 的特定环境中通过元表设置乘法运算符

Setting multiplication operator through metatable in specific environment in Lua

evaluation

lua

operators

metatable

meta-method