On Sat, Mar 07, 2020 at 04:55:06PM +0100, Hans Hagen wrote:
> > The problem can be fixed by always looking at stack slot -2 for the
> > returned node:
> actually we can as well accept nil then so that one can discard something
Returning `nil` is already supported: It is documented and also works
fine because `result` is always initialized to `null` (in packaging.c).
But I agree that handling that case explicitly in
`lua_appendtovlist_callback` might be a bit cleaner and also in some
cases slightly more efficient.
>
> if (lua_type(Luas, -2) == LUA_TUSERDATA) {
> halfword* p = lmt_check_isnode(Luas, -2);
> *result = *p;
> } else if (lua_type(Luas, -2) == LUA_TNIL) {
> *result = null;
> } else {
> normal_warning("append to vlist","error: node or nil expected");
> }
> if (lua_type(Luas, -1) == LUA_TNUMBER) {
> *next_depth = lmt_roundnumber(Luas, -1);
> *prev_set = 1;
> }
I assume lmt_... is the luametatex equivalent?
Marcel
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