Re: [Boost-Users] Re: uBLAS: reference to container data & iteratordeclaration

From: jhr.walter_at_[hidden]
Date: 2003-03-07 04:13:54

Hi,

[snip]

> > > I am not sure about your last statement. Do you mean a kind
> > > of  'vector_proxy' that can act as a placeholder to a row/column or
> > > another vector?
> >
> > No, I basically meant, I hope that you'll find appropriate  signatures
for
> > your functions. I still believe you'll either have to  use 'expressions'
or
> > have to enumerate all overloads for your 'data' types (and that could be
> > many ;-).
>
> So in a certain sense I can see the 'expression' that is stored in my
> functor as a 'reference' to my container data? I.e when the data of
> the container changes the evaluation of the expression will retrieve
> the current data?

Hm, more or less yes

> Sorry for my slow uptake on the matter. I think this comes from the
> fact that I still do not have a sound idea of what an 'expression' is
> to me from a point of usage. Can I see it as a bundle of funtions
> having certain parameter lists?

I'd tend to see it as the root of an expression tree build from class
objects (at compile time).

> What 'really' happens when I "e()(i,j)" ?

The expression is interpreted (at compile time ;-)

Best,

Joerg