Iterate through all the layers in the project

local count = 0
repeat
	local layer = moho.document:LayerByAbsoluteID(count)
	if layer then
	  count = count + 1
	  -- do whatever you like with the layer, for example print the name:
	  print(layer:Name())
	end
until not layer   
print("Total number of layers in the project: " .. count)