Re: Exit one Lua state from a (C) API function

[Mimmo Mane <pocomane_7a@...>]

On Thu, Feb 25, 2021 at 9:58 PM bel wrote:
> It cannot be just a luaL_error call, since this will be caught by a pcall in the Lua code.

Could a pcall wrapper be a good solution for you? Something like (not tested):

```
local propagate = {}
local oldpcall = pcall
pcall = function(f)

  local res = table.pack(oldpcall(f)) -- [1]

  -- If the "Propagate" request is found, it will forward the error to
the upper level
  if not res[1] and res[2] == propagate then
    error(res[2])
  end

  -- Otherwise, it behaves like the standard pcall
  return table.unpack(res)

end
```

then, a exit_to_c function can be defined as

```
local function exit_to_c()
  error(propagate)
end
```

(probably you need to wrap xpcall too)

Mimmo Mane

[1] Pack/unpack can be avoided with something like
local function result_check(f, ...)
    return (function(a, ...)
    if a == 'default' then
      return 'default', 1, 2, 3
    end
    return a, ...
  end)(f(...))
end
print(result_check(function() return 'foo','bar' end))
print(result_check(function() return 'default','bar' end))