lua which operators can be overloaded

Question

i know that it is possible to overload the addition operator in lua for tables. By doing:

foo = {
    value = 10
}
bar = {
    value = 15
}
mt = {
    __add = function(left,right)
        left.value = left.value + right.value;
        return left;
    end
}
setmetatable(foo,mt);

foo = foo + bar;
print(foo.value);

prints: 25

But my Question now is which other operators can you overload and if __add is used to access the + operator, how can you access other operators?

Answer 1

which other operators can you overload

Complete list of metamethods is described in Lua manuals: http://www.lua.org/manual/5.1/manual.html#2.8
http://www.lua.org/manual/5.2/manual.html#2.4
http://www.lua.org/manual/5.3/manual.html#2.4

if __add is used to access the + operator, how can you access other operators?

See the manual. Metamethods' description tells which operator triggers that exact metamethod.