Re: Strange way to determine whether it is Lua or C function

[Viacheslav Usov <via.usov@...>]

On Sun, Aug 23, 2020 at 5:26 PM Viacheslav Usov <via.usov@gmail.com> wrote:

> The coroutine business ensures that the test subjects never actually run.

As established in an erroneous spin-off bug thread, the yield results
in an error rather than a normal yield. Which suggests that coroutines
are not in fact a necessary means toward this end. Indeed, the
following code seems to achieve the same effect without coroutines:

local debug = require 'debug'

local function is_C_function(func)
  local x
  debug.sethook(
    function()
      if debug.getinfo(2, 'f').func == func then
        x = debug.getlocal(2, 2)
        error(0)
      end
    end,
    'c'
  )
  pcall(func)
  return not x
end
)

Cheers,
V.