[GiNaC-list] memory allocation, matrices

[Richard B. Kreckel]

Hi!

Marko Riedel wrote:

>Thanks! This thread is exactly what I was looking for. Can you briefly
>explain the meaning of reinterpret_cast<GiNaC::ex*>? Wouldn't
><GiNaC::ex*> be sufficient?
>  
>
The way you write it is not valid. I suppose you mean C-style cast 
(GiNaC::ex*) instead. Yes, you can as well write it using C-style cast. 
But you may wish to read a little bit in any textbook about C++ about 
arguments against C-style cast. The point is that reinterpret_cast<T*> 
is telling the reader a little bit more than (T*).

>Also, in GiNaC, if I have an expression
>that is actually a symbol, say, how do I determine at compile time
>what destructor to call, ~ex or ~symbol?
>  
>
I am not sure if it is such a good idea to do that with objects of class 
symbol. Why not always wrap the symbols in an ex in your code? The ex 
are supposed to be helpful when interfacing to environments where one 
has to give up on C++ types.

Anyway: If the object was constructed as a symbol statically, then you 
have to destroy it as a symbol. If the ex at compile time turns out to 
be a symbol, then, well, it's still just an ex holding a symbol and you 
have to destroy it as an ex.

>I will need to invoke the destructor explicitly in the deallocation
>code of my Objective C object.
>  
>
Ugh!

-richy.

-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>