vector.lua

local vector = {}
local vector_mt = {__name = "vector", __index = vector}

local function new(x, y, z)
    return setmetatable({
        x = tonumber(x) or 0,
        y = tonumber(y) or 0,
        z = tonumber(z) or 0,
    }, vector_mt)
end

function vector:add(v)
    return new(self.x + v.x, self.y + v.y, self.z + v.z)
end
vector_mt.__add = vector.add

function vector:sub(v)
    return new(self.x - v.x, self.y - v.y, self.z - v.z)
end
vector_mt.__sub = vector.sub

function vector:mul(k)
    return new(self.x * k, self.y * k, self.z * k)
end
vector_mt.__mul = vector.mul

function vector:div(k)
    return new(self.x / k, self.y / k, self.z / k)
end
vector_mt.__div = vector.div

function vector:unm()
    return new(-self.x, -self.y, -self.z)
end
vector_mt.__unm = vector.unm

function vector:dot(v)
    return self.x * v.x + self.y * v.y + self.z * v.z
end

function vector:cross(v)
    return new(self.y * v.z - self.z * v.y, self.z * v.x - self.x * v.z, self.x * v.y - self.y * v.x)
end

function vector:length()
    return math.sqrt(self.x * self.x + self.y * self.y + self.z * self.z)
end

function vector:normalize()
    return self:mul(1 / self:length())
end

function vector:tostring()
    return self.x .. "," .. self.y .. "," .. self.z
end
vector_mt.__tostring = vector.tostring

function vector:equals(v)
    return self.x == v.x and self.y == v.y and self.z == v.z
end
vector_mt.__eq = vector.eq

return {new = new}