Phil Bouchard
Founder
C.: (819) 328-4743
Well I believe a proposal should be open for debate, just like a thesis.
We both agree these overloads should be simplified but we disagree on the syntax.
I saw the recursive lambda thing and I think I already talked to you before regarding CV overloads but we were proposing the following syntax:
struct A
{
template <bool BC>
void foo() bool<BC>
{
}
};
And regarding the this generic overloading I still believe the following syntax is cleaner:
struct A
{
template <typename T>
bool compare(T const &);
};
template <typename C, typename T>
void C::compare(C const &)
{
...
}
Because with your syntax I could technically reassign "self":
struct A
{
template <typename C, typename T>
bool compare(this C & c, T const &);
};
template <typename C, typename T>
bool C::compare(this C & c, T const &) // redundant C
here
{
static C sc = C();
c = sc; // in theory we could do this unless you patch
the compilers with a new error for that specific case
}
--
Phil Bouchard
Founder
C.: (819) 328-4743
I meant that you should consider the incremental value of your proposal over p0847, which is on track for c++23 unless serious issues crop up
On Sat, Mar 7, 2020, 19:04 Phil Bouchard <phil@fornux.com> wrote:
The syntaxes are way different:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p0847r4.html
In your case the compiler will have to change all of its rules for the number of parameters "operator" overloads. For example:
struct A
{
int value;
...
template <typename Self>
bool operator < (this Self && self, A const & a) // 2 parameters... ok
{
return self.value < a.value;
}
bool operator < (A const & a) // 1 parameter... ok
{
return value < a.value;
}
};
--
Phil Bouchard
Founder
C.: (819) 328-4743
On 3/7/20 1:35 PM, Gašper Ažman wrote:
P0847
On Sat, Mar 7, 2020, 18:33 Phil Bouchard via Std-Proposals <std-proposals@lists.isocpp.org> wrote:
--Alright, I'm pretty sure this is not implemented yet. Suppose you have:
struct A
{
int value;
...
template <typename T>
int compare(T const & t) const;
}
struct B
{
int value;
...
template <typename T>
int compare(T const & t) const;
}
Then a generic way to define the same functionality for all classes would be to have a "template 'this'":
template <typename C, typename T>
inline int C::compare(T const & t) const
{
return value == t.value ? 0 : value < t.value ? -1 : 1;
}
(Please include my email address in your replies)
--
Phil Bouchard
Founder
C.: (819) 328-4743
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