state = start
    input->remember-start-position
    
    while (input.has-more) {
        transition = transition-for (state, input.current-char)
        
        if (transition.is-good) {
            state = transition.state                    # move
            
            if (state.accepts) {                        # memo
                memo.type = state.type
                input->remember-accept-position
            }
            input->advance                              # advance
        } else {
            push output-queue, token (                  # token
                memo.type
                input.accepted-string
            )
            input->rewind                               # rewind
            state = start                               # restart
        }
    }