Fix issue #135

[saccarosium]

Now opt should work as expected.

[savq]

Just for future reference, the tri-state map of opt is:

cfg \ args	1	0	nil
1	1	0	1
0	1	0	0

We can ignore the case cfg.opt == nil because cfg will always have a default value. One way to simplify this would be:

local opt = args.opt or cfg.opt and args.opt == nil

This is very similar to your suggestion. Although it's clearer to check for == nil instead of ~= false because we're interested in the case cfg.opt == true and args.opt == nil.

We can test this is the correct behavior with the following snippet:

local co = coroutine

local states = co.wrap(function()
  co.yield(false, false)
  co.yield(false, true)
  co.yield(false, nil)
  co.yield(true, false)
  co.yield(true, true)
  co.yield(true, nil)
  return
end)

for c, a in states do
  local opt = a or c and a == nil
  print(string.format("c = %s; a = %s; opt = %s", c, a, opt))
end

Which outputs:

c = false; a = false; opt = false
c = false; a = true; opt = true
c = false; a = nil; opt = false
c = true; a = false; opt = false
c = true; a = true; opt = true
c = true; a = nil; opt = true

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• closes opt = true not respected #135

[saccarosium]

Should be ok