lua - Error while useing a Method of a Metatable 'attempt to call method (a nil value)' -
i error 'attempt call method 'dot' (a nil value)' while running following code:
-- vector2 class vector2 = {x = 0, y = 0, magnitude = 0, unit = nil} function vector2.new(xvalue,yvalue) local tmp = {} setmetatable(tmp,vector2) tmp.x = xvalue tmp.y = yvalue tmp.magnitude = math.sqrt(tmp.x * tmp.x + tmp.y * tmp.y) if tmp.magnitude ~= 1 tmp.unit = tmp/tmp.magnitude else tmp.unit = tmp end return tmp end -- arithmetic function vector2.__add(a,b) if getmetatable(a) == getmetatable(b) return vector2.new(a.x+b.x, a.y+b.y) end end function vector2.__sub(a,b) if getmetatable(a) == getmetatable(b) return vector2.new(a.x-b.x, a.y-b.y) end end function vector2.__mul(a,b) if tonumber(b) ~= nil return vector2.new(a.x*b, a.y*b) end end function vector2.__div(a,b) if tonumber(b) ~= nil return vector2.new(a.x/b, a.y/b) end end function vector2.__unm(tmp) return vector2.new(-tmp.x, -tmp.y) end -- comparisons function vector2.__eq(a,b) if getmetatable(a) == getmetatable(b) if a.x == b.x , a.y == b.y return true else return false end end end function vector2.__lt(a,b) if getmetatable(a) == getmetatable(b) if a.magnitude < b.magnitude return true else return false end end end function vector2.__le(a,b) if getmetatable(a) == getmetatable(b) if a.magnitude <= b.magnitude return true else return false end end end -- functionals function vector2.__tostring(tmp) return tmp.x..", "..tmp.y end function vector2:dot(b) return self.x*b.x + self.y*b.y end function vector2:lerp(b,amn) return self + (b-self)*amn end print(vector2.new(1,0.3).magnitude) print(vector2.new(1,0):dot(vector2.new(0,1))) i'm not understanding i've done wrong, lend hand, have lua experience, have started learning how use metatables, i'm new @ point, running using scite, luaforwindows. error on last line, line above runs perfectly
you have forgotten set __index field:
vector2 = {x = 0, y = 0, magnitude = 0, unit = nil} vector2.__index = vector2 
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