A few years ago, I ran an essay I was writing on Frost through a
grammar-checking program called Grammatik IV. When the program
got to a point in the essay where I had quoted the line "And miles
to go before I sleep," it stopped, and offered the following advice:
"The context suggests that the objective rather than the
nominative first-person singular pronoun is called for here."
Miles to go before *me* sleep!
To be fair to the software, it did offer at the end a percentage of
passive to active constructions used throughout the entire essay--I
have no idea how it arrived at this figure, or even if it was accurate,
but I did think this was the program's most useful feature--could
you imagine being able to tell first-year students that their essays
were 56.7 % passive!