Closures and Upvalues

Lua supports closures, which are functions that capture variables from their surrounding scope.

Example:

function outer()
  local count = 0
  return function()
    count = count + 1
    return count
  end
end

counter = outer()
print(counter()) -- Output: 1
print(counter()) -- Output: 2

Explanation: The inner function remembers the value of count even after outer() finishes execution. This is a closure in action.