We used to do like this instead of putting all command line processing
code within one gigantic switch statement. It is converted to a switch
in r188958, which introduced InputGraph.
Making bunch of ifs to one switch statement with bunch of cases weren't
needed for InputGraph, so I don't know why that change was made in the
In this patch I roll that change back. Now all "break"s are removed,
and the nesting is one level shallow.