Empty Table Manipulation

[Kristopher Lohmuller <tervalas@...>]

I am a novice user of Lua so please excuse the lack of knowledge.

I'm trying to perform checks and other functions on an empty table, such 
as table.getn(table). This was something I thought would give a result 
of zero as per the first edition of Programming in Lua. However, I am in 
actuality getting an error for trying to index a nil value. What is 
upsetting more is that I've seen another script use this same call and 
not generate an error.

To give more clarity on code:

disp = {};
if ((not disp) or (table.getn(disp)==0)) then
  do stuff
end

Further on I try to use the same variable in a for statement:

for i,d in disp do
  do things
end

This also is generating an error about trying to access a nil value. 
Again, this is an exact copy of code that works, yet mine does not. Any 
suggestions?