Re: How to clone a table in LJ2-friendly way?

["Dimiter \"malkia\" Stanev" <malkia@...>]

Here is one more version, still not lj2 friendly, but for some reason 
very much lua friendly (no closure, using directly next iterator):

malkia ~/p/luamarca $ ./run_benchmark.sh bench/tclone.lua 100000
Results:
lua
-------------------------------------------------------------------
                name |     rel | abs s / iter = us (1e-6 s) / iter
-------------------------------------------------------------------
             tclone6 |  1.0000 |   2.94 /     100000 = 29.400000 us
             tclone5 |  4.9592 |  14.58 /     100000 = 145.800000 us
             tclone2 |  5.6190 |  16.52 /     100000 = 165.200000 us
          lua_nucleo |  5.8401 |  17.17 /     100000 = 171.700000 us
luajit -O
-------------------------------------------------------------------
                name |     rel | abs s / iter = us (1e-6 s) / iter
-------------------------------------------------------------------
             tclone6 |  1.0000 |   1.45 /     100000 = 14.500000 us
             tclone5 |  1.1103 |   1.61 /     100000 = 16.100000 us
             tclone2 |  1.3034 |   1.89 /     100000 = 18.900000 us
          lua_nucleo |  1.5241 |   2.21 /     100000 = 22.100000 us

local tclone6
do
  local function impl(t, visited, rtimes)
    if visited[t] then
      error("recursion detected")
    end

    if rtimes == 128 then
      rtimes = 1
      visited[t] = true
    end

    local r = {}
    local k, v = next(t)
    while k do
       if type(k) == "table"  then
	  if type(v) == "table" then
	     r[impl(k, visited, rtimes + 1)] = impl(v, visited, rtimes + 1)
	  else
	     r[impl(k, visited, rtimes + 1)] = v
	  end
       elseif type(v) == "table" then
	  r[k] = impl(v, visited, rtimes + 1)
       else
	  r[k] = v
       end
       k, v = next(t, k)
    end

    if rtimes == 1 then
      visited[t] = nil
    end

    return r
  end

  tclone6 = function(t)
    if type(t) == "table" then
      return impl(t, { }, 1)
    end

    return t
  end
end


On 8/22/11 9:37 AM, Dimiter "malkia" Stanev wrote:
> On 8/22/11 3:29 AM, Alexander Gladysh wrote:
> > On Sun, Aug 21, 2011 at 05:03, Dimiter "malkia"
> > Stanev<malkia@gmail.com> wrote:
> > > Here is a little bit more optimized version.
> >
> > <...>
> >
> > Thank you, very interesting!
> >
> > Can I reuse it in lua-nucleo (under MIT license)?
> >
> > Alexander.
>
> Yes, no problem, and license of your choosing (I usually go with MIT
> too, as lua and luajit are there, no need to make it more complex).
>
> Cheers!