if I call a function foo(t[1]) through the C API, can I in any way see what table and what index is as argument, in this case t and 1?
The problem at hand is a function move_card(card, table_slots[0]) where I move a card from one slot on a game area to another one. table_slots can also be hand or player_slots. This can be solved using a metatable, stating the name of the table being accessed. But the index is impossible to solve, or is it? table_slots[0] can be a card table, or an overlay or stack (arrays of cards), or nil if it's empty, as could player_slots. But what I need to know is in fact if it's from a table_slots or player_slots.
Could I hack some code analysis? Like, get the line where the function call is made, and then grep the index through a regexp? I could send table_slots[0] as a string, also, like move_card(card, "table_slot[0]"). Not as elegant, but still working.
No, once a value reaches a function, be it C or Lua, its origins are lost.
On the other hand, when an error occurs in Lua, the runtime system tries quite a bit to reconstruct the origin of the relevant values, but it does not always succeeds.