Re: Extract a list of keys from table

["Alexander Gladysh" <agladysh@...>]

On Sat, Jul 19, 2008 at 12:12 AM, Alexander Gladysh <agladysh@gmail.com> wrote:

> Methods:
>
> * noop -- function() end
> * c -- Implementation in plain C (module built with -O2 by Apple's GCC 4.0.1)
> * generated -- Pregenerated version (return t[a1], t[a2]... t[aN])
> * unpack -- table creation
> * recursive -- Recursive call version

By the way. The 'generated' method is based on this function:

  local generate_extractor = function(n)
    assert(type(n) == "number")
    local a, r = {}, {}
    for i = 1, n do
      a[i], r[i] = 'a'..i, 't[a'..i..']'
    end
    return assert(
        loadstring(
            [[return function(t,]]..table_concat(a, ",")..[[)return
]]..table_concat(r, ",").."end",
            "extract_keys_"..n
          )
      )()
  end

Is it possible somehow to implement it without loadstring, but via
means of return function(t, ...) <...> end?

Also, since we have benchmark up and running, does anyone have any
other however crazy idea on the alternative implementation of
extract_keys?

Alexander.