10:55 AM
Subject: Re: [boost] possible addition to operators library
Daniel Frey wrote:
Daniel Frey wrote:
No problem. IIRC it was Peter Dimov who came up with the safe-bool
idiom first. At least I saw it first from him. Another way which
works but results in worse error messages
Sam Partington wrote:
Hi all,
Hate to sound pushy, but I've no answer on this, were the patches ok? Would
you like me to repost them?
Or should I just drop it?
No, please don't drop it. I think it's a good idea, but I haven't found
the time to look at your patches closely. I will try
Sam Partington [EMAIL PROTECTED] writes:
Hi all,
Hate to sound pushy, but I've no answer on this, were the patches ok? Would
you like me to repost them?
Or should I just drop it?
The code looks OK, but the submission won't be complete without
patches for the docs and tests.
--
Dave
At 11:08 AM 3/7/2003, David Abrahams wrote:
Sam Partington [EMAIL PROTECTED] writes:
Hi all,
Hate to sound pushy, but I've no answer on this, were the patches ok?
Would
you like me to repost them?
Or should I just drop it?
The code looks OK, but the submission won't be complete without
Daniel Frey wrote:
Daniel Frey wrote:
No problem. IIRC it was Peter Dimov who came up with the safe-bool
idiom first. At least I saw it first from him. Another way which
works but results in worse error messages is this:
template class T, class B = ::boost::detail::empty_base
struct
Hi all,
Sorry I've been off air for a bit. I'll try to answer as much as I can in
this email.
Daniel Frey wrote:
I also think it would be fair to mention Dave as a contributor, too,
as he provided the way to reduce the overhead.
Of course, that bit was still there from the first time through,
Sam Partington wrote:
Daniel Frey wrote:
I also think it would be fair to mention Dave as a contributor, too,
as he provided the way to reduce the overhead.
Of course, that bit was still there from the first time through, also
whoever came up with the original unspecified-bool-type
Sam Partington [EMAIL PROTECTED] writes:
Hi,
While making myself an interim shared_resource class, I found myself reusing
the shared_ptr safe-bool conversion, and thought that really the idiom ought
to go into the operators library.
I am unsure about the name, but for now bool_testable
Essentially you supply a operator! and it supplies an unspecified-bool-type
conversion operator.
Nice idea! I already had something similar in mind, but you managed to
make it really generic.
//Key
//T: primary operand type
//t: values of type T
// TemplateSupplied Operations
Daniel Frey wrote:
The only problem I see is that an instance of safe_bool_conversion is
created which is not really needed. I suggest to rely on the operator!
provided by T:
template class T, class B = ::boost::detail::empty_base
struct bool_testable : B
{
private:
typedef bool
Daniel Frey wrote:
Nice idea! I already had something similar in mind, but you managed to
make it really generic.
Not really, all I've done is to borrow the code from shared_ptr, and to put
into a shape like one of the existing unary operator helpers in
operator.hpp. Thanks anyway though :-)
Sam Partington [EMAIL PROTECTED] writes:
I thought of this too, but this limits the user to using a member based
operator!. So I couldn't do this :
class A : public boost::bool_testableA
{
public:
int get();
};
bool operator!(const A a)
{
return a.get() == 0;
}
Of course
Sam Partington wrote:
I thought of this too, but this limits the user to using a member based
operator!. So I couldn't do this :
class A : public boost::bool_testableA
{
public:
int get();
};
bool operator!(const A a)
{
return a.get() == 0;
}
Of course I've never
I think I agree, we want to provide as little restrictions as possible.
Also seems to me that anyone who declares a global template operator!
deserves some problems!
So, now with David's suggestion, I've attached what I propose.
I've tested to a small extent on MSVC6 and gcc 2.95, which are all
Daniel Frey [EMAIL PROTECTED] writes:
Sam Partington wrote:
I thought of this too, but this limits the user to using a member based
operator!. So I couldn't do this :
class A : public boost::bool_testableA
{
public:
int get();
};
bool operator!(const A a)
{
return
Sam Partington [EMAIL PROTECTED] writes:
I think I agree, we want to provide as little restrictions as possible.
Also seems to me that anyone who declares a global template operator!
deserves some problems!
I don't know why you think so.
So, now with David's suggestion, I've attached what
Daniel Frey [EMAIL PROTECTED] writes:
That won't work as you made it a nested struct so it is still different
for all instantiations. I think Dave meant to go for this one:
Yup, that's what I meant. BTW, so this safe_bool thing can get
further re-used it might make sense to make a special
David Abrahams wrote:
Daniel Frey [EMAIL PROTECTED] writes:
That won't work as you made it a nested struct so it is still different
for all instantiations. I think Dave meant to go for this one:
Yup, that's what I meant. BTW, so this safe_bool thing can get
further re-used it might
Daniel Frey [EMAIL PROTECTED] writes:
David Abrahams wrote:
Daniel Frey [EMAIL PROTECTED] writes:
That won't work as you made it a nested struct so it is still different
for all instantiations. I think Dave meant to go for this one:
Yup, that's what I meant. BTW, so this safe_bool
On Tue, 25 Feb 2003, David Abrahams wrote:
namespace boost
{
struct safe_bool
{
int value;
typedef int safe_bool::*type;
};
}
struct myclass
{
operator boost::safe_bool::type() const
{
return expression ? boost::safe_bool::value : 0;
}
};
20 matches
Mail list logo
