Re: CINT improvement news

From: Nick van Eijndhoven (Nick@fys.ruu.nl)
Date: Tue Jul 01 1997 - 09:32:28 MEST


Hi Masa,
I have been out for a day or 2 and am now reading my emails in reverse
order as they came in, so maybe you have already sent me another mail about
the subject. However, from the scenario below I myself would prefer
method 1) to be implemented since to me this seems to be in line with the
ANSI proposed standard. I am not at all a specialist in C++ and therefore
let myself always guide by some text books adhering the ANSI standard.
Therefore it is important for me that the ROOT/CINT functionality should
at least provide a fully ANSI C++ compatible environment, such that
a simple user like me should no difference in coding for e.g. g++ to
compile code, or coding fopr ROOT/CINT.

                                                    Cheers,
                                                     Nick.

P.S. I hope the CINT major improvements will also cure the problem I
     recently mentioned to you.

*----------------------------------------------------------------------*
 Dr. Nick van Eijndhoven                Department of Subatomic Physics
 email : nick@fys.ruu.nl                Utrecht University / NIKHEF
 tel. +31-30-2532331 (direct)           P.O. Box 80.000
 tel. +31-30-2531492 (secr.)            NL-3508 TA Utrecht
 fax. +31-30-2518689                    The Netherlands
 WWW : http://www.fys.ruu.nl/~nick      Office : Ornstein lab. 172
 ----------------------------------------------------------------------
 tel. +41-22-7679751 (direct)           CERN PPE Division / ALICE exp.
 tel. +41-22-7675857 (secr.)            CH-1211 Geneva 23
 fax. +41-22-7679480                    Switzerland
 CERN beep : 13+7294                    Office : B 160 1-012
*----------------------------------------------------------------------*

*** Masaharu Goto wrote :
> 
> Rooters,
> 
>  I made a major improvement on CINT C++ interpreter.  
> 
> Operator precedence:
>   CINT used to have different operator precedence to ANSI standard. This
>  part was one of the oldest code which was rather messy. This time, I 
>  completely re-write this part with a better implementation. Operator
>  precedence should be compliant to the standard now.
>  The new version will be copied to CERN soon.
> 
> 
>  And next is a question to Rooters about another enhancement.
> 
> Operator new:
>   I'd like to make an improvement on 'operator new' handling. Before I
>  make a change, I'd like to ask ROOT users about my idea.  Now, you can 
>  only use default operator new provided by OS and ROOT/CINT.  You could 
>  overload operator new, but it is not a simple job. I have following 
>  alternatives of future enhancement.
> 
>  1) ANSI/ISO standard says there is not default operator new with arena
>    argument. Gussing that this is the most popular way of using overloaded
>    new, CINT provides embedded operator new with arena argument. With
>    this enhancement, a user can write following macro without having his
>    own operator new(). 
> 
> 	 class Txxx;
> 	 char buf[10000];
>          Txxx *p1 = new Txxx;
> 	 Txxx *p2 = new((void*)buf) Txxx;
> 	 Txxx *p3 = new((void*)buf) Txxx[10];
> 
>  2) Allow user to overload operator new at his one risk. Overloading
>    operator new in interpreter environment is simple. But doing so in
>    compiled code is not. One has to go throught painful thinking. I
>    do not explain in detail , but there is an inevitable reason.
> 
>  I prefer to implement 1).  Give me your opinion.
> 
> Masaharu Goto
> 



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