Attempt to index local 'self' (a nil value)

Question

I have a problem with classes. I got below error: Attempt to index local \'self\' (a nil value) When I call the getter method of below class. Item.lua file:

Answer 1

Change:

assert_equal(1, item.getInterval())

to:

assert_equal(1, item:getInterval())

In Lua, it was some ridiculous for error reporting. From class point of view, the .getInterval() method should called with a self parameter, while the :getInterval() method is implicitly included the self parameter. And the syntax error should labeled in the called point, not the definition-body of getInterval().

In traditional, while you miscalled a method, it was not the method's fault, but the caller.