Table array performance improvement using dot notation

[David Crayford <dcrayford@...>]

I'm not sure if I have seen this documented although I know that Lua has optimization for tables used as arrays. But I didn't expect that would be due to using dot notation. How can this be?

local a = {}           
for i = 1, arg[1]  do  a[i] = i * i end   
DOC:/u/doc/lua: >time lua lbench1.lua 2000000

real 0m 0.35s
user 0m 0.18s
sys 0m 0.06s

local a = {}
for i = 1, arg[1] do a.i = i * i end

DOC:/u/doc/lua: >time lua lbench1.lua 2000000

real    0m 0.19s
user    0m 0.12s
sys     0m 0.04s