[antlr-interest] MSVC 6.0 Compiler accuracy?

[Sohail Somani]

The standards compatible mode is upgrade to 7.1 or later. VC6 is
prestandard.

On Mon, 2006-05-22 at 11:23 -0400, Andy Tripp wrote:
> According to the ISO/IEC 14882:1998 C++ standard, all those
> declarations inside conditions are, in fact, legal. So if MSVC++ doesn't 
> accept them,
> it's a problem with MSVC++ - perhaps there's a "standards compatible 
> mode" option?
> Yes, each of these statements opens a new scope, the variable is 
> declared once, and
> its scope is what is should be :)
> 
> Andy
> 
> Wigg, J D wrote:
> 
> > I am the latest author of the C++ parser available from the Antlr website.
> >  
> > It has been brought to my attention that it does not parse the 
> > following properly because of declarations in conditions,
> >  
> > bool fun()
> >  {
> >  int i, j, k, l = 0;
> >  
> >  if(int i = 1)   // MSVC++ 6.0 accepts declaration and redefinition of i.
> >   {
> >   printf("%d ",i);
> >   }
> >  
> >  switch(int j = 1)   // MSVC++ 6.0 accepts declaration and 
> > redefinition of j.   
> >   {
> >  case 1:
> >   return true;
> >  default:
> >   return false;
> >   }
> >  
> >  while(int k = 2)   // MSVC++ 6.0 accepts declaration and redefinition 
> > of k.
> >   {
> >   k--;
> >   printf("%d ",k);
> >   }
> >  
> >  for(int i = 5; int l = i; i--) // MSVC++ 6.0 rejects redefinition of 
> > i and
> >   {                                // declaration in condition  
> >   printf("%d ",l);
> >   }
> >  
> > I have not made allowance for the apparently legal possibility 
> > according to reliable grammar definitions of declaring a variable in 
> > the condition statement of these four statements.
> >  
> > I am told that gcc 3.3.3 accepts the declaration in the above "for" 
> > statement.
> >  
> > It therefore looks as though MSVC++ 6.0 is incorrect in this instance. 
> > I would be grateful if someone would confirm this. Perhaps there is a 
> > later version of MSVC which parses this "for" statement correctly?
> >  
> > I presume that each of these four statements opens a new scope.
> >  
> > I have been parsing various C++ programs for some years now and never 
> > come across the declaration of variables in conditions. I suppose this 
> > is not surprising. I can't think why one would want to do it. It seems 
> > illogical to allow this in iteration statements since the condition 
> > would appear to redeclare the variable on each iteration!
> >  
> > It would be interesting to hear of any use for this feature.
> >  
> > David
> > Centre for Systems and Software Engineering
> > London South Bank University
> > UK.
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