🚀 go-pugleaf

In article <4ikkbu$b5u@engnews1.Eng.Sun.COM>, clamage@Eng.Sun.COM wrote:

: In article 1403961511110001@193.131.176.202, sdouglas@armltd.co.uk
: (scott douglass) writes:
: >[...]
: >Bonus question:  why does the grammer allow only the '=
: >assignment-expression' form:
: 
: >[grammar to allow 'while (T t(i)) { /* ... */]
: 
: I think the general case could lead to ambiguities in parsing. If a
: function call can possibly be interpreted as a variable definition, then
: it is a variable definition. That could lead to unexpected behavior
: which would be difficult to track down.
: 
: You can always write the same thing with "=" notation:
:         while( T t = T(i) ) { ... }
: This rewrite is not guaranteed to be as efficient, but most compilers
: do optimize away the extra copy.

It is not the same if the copy-constructor for T is private (say, as part
of preventing copying of Ts) and the constructor from the type of 'i' is
public, as is the case in at least one class I have.  Then only the 'T
t(i)' form is legal.
    --scott
---
[ comp.std.c++ is moderated.  To submit articles: Try just posting with your 
                newsreader.  If that fails, use mailto:std-c++@ncar.ucar.edu
  comp.std.c++ FAQ: http://reality.sgi.com/austern/std-c++/faq.html
  Moderation policy: http://reality.sgi.com/austern/std-c++/policy.html
  Comments? mailto:std-c++-request@ncar.ucar.edu 
]