- Adds StructOpt argument parsing
- Accepts `-` as a shorthand for standard input
- Defaults to `-` if no path is given
- Errors out via ExitFailure
For such a small amount of code, there's quite a lot happening here that I
don't understand yet.
Takes stdin and splits on whitespace (I'm guessing this only supports
UTF-8 at the moment). Takes no flags, doesn't do anything fancy to
uniq-ify words, strip punctuation, etc. Doesn't yet know how to open a
file.