Ah, of course. That makes good sense -- sorry for the bother. However, I have two follow-ups.
The fact that the last indented line under "plays a Library" often is "discards <action-card(s)>" is a tad confusing. That is, in most cases it makes sense, in that the AI is choosing not to play the discarded card(s), but I cannot always account for the number of cards in the AI's hand -- in most of the cases where the numbers don't add up, I assume that the missing cards are victory point cards...which is fine but why aren't these noted in an analogous "discard" message?
And, there's still one case that I don't understand -- Turn 13: assuming that Revenge Witch starts with three cards and plays the Library, draws seven (total) cards, sets aside two (total), and discards two, she should have five cards left (3-1+7-2-2), and yet she somehow plays 2 each of coppers, silver, and gold, for a total of six! What am I missing?
(By the way, I think that this implementation of Dominion is beautiful and nicely playable, and I've learned a lot from the AI's play!)