regular-state::process (input) {
        input->remember-accept-position if (self->accepts)  # memo-2
        input->advance                                      # advance
    }
    
    error-state::process (input) {
        push (output-queue, token {                     # token
            type = last-accept.type
            value = input->last-accepted-string
        })
        input->rewind                                   # rewind
    }
    
    error-state::transition-for (char) {
        return (start)                                  # restart-1
    }

    start-state::process (input) {
        input->remember-starting-position               # restart-2
    }
    

    state = start-state
    
    while (input->has-more) {
        last-accept = state if (state->accepts)         # memo-1
        state->process (input)
        state = state->transition-for (input->current-char)
            || error-state                              # move
    }