and yes i said yes and i will yes

It means that after all the torment,after all the troubles of the day - Joyce wanted to end Ulysses on "the most positive word in the English language".He had always been quite sure that he wanted to end Ulysses in this manner - especially the last word.
the whole final episode only has two punctuations.Just go with it ...it you just read it,the punctuation will become clear ...and you'll get into the rhythm