Embedding Lua in an application

[Paul Beckingham <paul@...>]

Hello Lua community.

I have a stylistic question.  I am embedding Lua in an application, such that Lua becomes the language in which hooks are written, to extend or integrate the product.  While I am having no technical difficulties (a testament to your beautiful implementation), I do have a few design decisions to make, and I don't want to end up with something that is not in the spirit of Lua, or Lua-ish if you will.

In the product, an event occurs, which triggers the execution of a Lua script.  There are actually many events, but let's just focus on one, because they are all to be handled in a similar manner.

Option 1)

The product can construct a context (variables and table(s)?) and pass them to the Lua function, which can modify the context, which will then be re-integrated back on the product side.
Pro: Simple function which simply does what it wants with the data.
Con: There is a cost to marshaling the data in two directions, even if it isn't used.

Option 2)

The product passes a handle to the Lua script.  The product then implements a series of functions that the Lua can call, to get more data, modify data.
Pro: Minimal initial data transfer, marshaling on demand
Con: ?

The product is written in C++, and in one run I might make 300 Lua calls to the same function.

I'm leaning towards option 2, but maybe there is a third I'm not aware of.  Does anyone have any advice on "the Lua way" to do this?

Thank you.
Paul Beckingham