Formatter events?  Nested for viewing pleasure.

What else does a formatter need to know?

feature(name, line, file, language, etc...)
  scenario(keyword, name, line)
    step(result, keyword, name, line)
    step(result, keyword, name, line)
  scenario_end(result)
feature_end(result)

feature(name, line, file, language, etc..)
  background(keyword, name, line)
    step(result, keyword, name, line)
    step(result, keyword, name, line)
    step(result, keyword, name, line)
  background_end(result)
  scenario_outline(keyword, name, line)
    examples(keyword, name, line)
      example(keyword, name, line)
        step(result, keyword, name, line)
        step(result, keyword, name, line)
        step(result, keyword, name, line)
      example_end(result)
    examples_end(result)
  scenario_outline_end(result)
  background(keyword, name, line)  #same background as before
    step(result, keyword, name, line)
    step(result, keyword, name, line)
    step(result, keyword, name, line)
  background_end(result)
  scenario(keyword, name, line)
    step(result, keyword, name, line)
    step(result, keyword, name, line)
  scenario_end(result)
feature_end(result)
.
.
.

Maybe crazy idea: have gherkin send these same events (with empty results), allow multiple listeners for the gherkin parser, too.

Would make a 'progress' formatter doable, since it could count scenarios/steps during parsing.