engraver question: how to define an array to store events?

[Marc Hohl]

Hello list,

while trying to get more insight into the engraver stuff, I encountered a
problem. I hope I can explain it:

I need some kind of a array of vectors:

vector<Stream_event*> slot_[max];

where I can store events later on by calling

slot_[i].push_back (event);

The index i lies in a fixed range from 0 to some value max, but it
isn't processed sequentially, so the calculations could start with i=4,
then comes i=0 etc.

As far as I understand c++, I cannot access i=4 directly if i=0...3
weren't accessed before.

So I tried to initialize the vector within initialize () as follows:

void
My_engraver::initialize ()
{
  static int const max = 12;
  vector<Stream_event*> slot_[max];
  for (int i = 0; i < max; i++)
     slot_[i] = 0;
};

but then slot_[] and max are not accessible in process_music ();

When I move the declarations to

class My_engraver : public Engraver
{
.
.
.
private:
  static int const max = 12;
  vector<Stream_event*> slot_[max];
.
.
.
}

void
My_engraver::initialize ()
{
  for (int i = 0; i < max; i++)
     slot_[i] = 0;
};

then I got

error: no match for 'operator=' in 
'((My_engraver*)this)-My_engraver::slot_[i] = 0'

How can this be solved? Or is there a better approach to store events in 
an array
the way I described above?

Thanks in advance!

Marc