• =?UTF-8?B?Tm9yZGzDtnc=?= (8/8) Jan 15 2017 Is there a way to query at compile-time whether a call to
• =?UTF-8?B?Tm9yZGzDtnc=?= (10/11) Jan 15 2017 Further, overloading such as
• kinke (4/6) Jan 15 2017 According to
• =?UTF-8?B?Tm9yZGzDtnc=?= (18/24) Jan 15 2017 This
• =?UTF-8?B?Tm9yZGzDtnc=?= (4/16) Jan 15 2017 given that

=?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

Is there a way to query at compile-time whether a call to

     f(T)(auto ref const T x)

passed the variable `x` from a l-value or r-value?

A call to `isRef!T` inside the function `f` is always `false` for 
`l-value` and `r-value` passing.

I need this to detect automatic delayed evaluation of 
sub-expressions in my GNU MP wrapper at

https://github.com/nordlow/gmp-d

=?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

On Sunday, 15 January 2017 at 14:33:25 UTC, Nordlöw wrote:
 Is there a way to query at compile-time whether a call to

Further, overloading such as

     struct S { int x, y; }
     static f(in S s) {}
     static f(const ref S s) {}
     f(S.init);
     S s;
     f(s);

fails as

     declaration f is already defined

kinke <noone nowhere.com> writes:

On Sunday, 15 January 2017 at 14:33:25 UTC, Nordlöw wrote:
 A call to `isRef!T` inside the function `f` is always `false` 
 for `l-value` and `r-value` passing.

According to 
https://dlang.org/spec/template.html#auto-ref-parameters, it 
should be `__traits(isRef, x)`.

=?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

On Sunday, 15 January 2017 at 17:00:41 UTC, kinke wrote:
 On Sunday, 15 January 2017 at 14:33:25 UTC, Nordlöw wrote:
 A call to `isRef!T` inside the function `f` is always `false` 
 for `l-value` and `r-value` passing.

 According to 
 https://dlang.org/spec/template.html#auto-ref-parameters, it 
 should be `__traits(isRef, x)`.

This

     struct S { int x, y; }
     void f()(auto ref const S s)
     {
         pragma(msg, "type:", typeof(s), " isRef:", isRef!s);
     }
     f(S.init);
     S s;
     f(s);

prints

     type:const(S) isRef:false
     type:const(S) isRef:true

I made the mistake of incorrectly using

     isRef!S

when I should have used

     isRef!s

Thanks!

=?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

On Sunday, 15 January 2017 at 17:41:36 UTC, Nordlöw wrote:
 This

     struct S { int x, y; }
     void f()(auto ref const S s)
     {
         pragma(msg, "type:", typeof(s), " isRef:", isRef!s);
     }
     f(S.init);
     S s;
     f(s);

 prints

     type:const(S) isRef:false
     type:const(S) isRef:true

given that

     enum isRef(alias fn) = __traits(isRef, fn);

:)