• =?UTF-8?B?Tm9yZGzDtnc=?= (8/8) Jan 11 2018 How do I check whether an aggregate member function (call for a
• Per =?UTF-8?B?Tm9yZGzDtnc=?= (12/20) Jan 11 2018 Is this an ok implementation:
• Simen =?UTF-8?B?S2rDpnLDpXM=?= (10/21) Jan 11 2018 Seems to be working fine. I'd go with this version for perhaps a
• Seb (6/29) Jan 11 2018 Author of hasFunctionAttributes here.

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

How do I check whether an aggregate member function (call for a 
specific argument) is  nogc or not?

I want to check whether

     Allocator.allocate(1)

(for a any Allocator) is  nogc or not?

Is

https://dlang.org/phobos/std_traits.html#hasFunctionAttributes

the way to do it?

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

On Thursday, 11 January 2018 at 12:24:36 UTC, Nordlöw wrote:
 How do I check whether an aggregate member function (call for a 
 specific argument) is  nogc or not?

 I want to check whether

     Allocator.allocate(1)

 (for a any Allocator) is  nogc or not?

 Is

 https://dlang.org/phobos/std_traits.html#hasFunctionAttributes

 the way to do it?

Is this an ok implementation:

enum bool isNogc(alias fun) = (isCallable!fun &&
                                (functionAttributes!fun &
                                 FunctionAttribute.nogc));

 safe pure nothrow  nogc unittest
{
     static int foo(int x)  nogc pure nothrow;
     static int goo(int x) pure nothrow;
     static assert(isNogc!foo);
     static assert(!isNogc!goo);
}

Simen =?UTF-8?B?S2rDpnLDpXM=?= <simen.kjaras gmail.com> writes:

On Thursday, 11 January 2018 at 12:32:54 UTC, Per Nordlöw wrote:
 Is this an ok implementation:

 enum bool isNogc(alias fun) = (isCallable!fun &&
                                (functionAttributes!fun &
                                 FunctionAttribute.nogc));

  safe pure nothrow  nogc unittest
 {
     static int foo(int x)  nogc pure nothrow;
     static int goo(int x) pure nothrow;
     static assert(isNogc!foo);
     static assert(!isNogc!goo);
 }

Seems to be working fine. I'd go with this version for perhaps a 
bit more brevity and clarity:

enum bool isNogc(alias fun) = hasFunctionAttributes!(fun, 
" nogc");

Both functionAttributes and hasFunctionAttributes already check 
that the argument is a callable (which function attributes should 
"foo" have?), so that's unnecessary.

--
   Simen

Seb <seb wilzba.ch> writes:

On Thursday, 11 January 2018 at 13:18:47 UTC, Simen Kjærås wrote:
 On Thursday, 11 January 2018 at 12:32:54 UTC, Per Nordlöw wrote:
 Is this an ok implementation:

 enum bool isNogc(alias fun) = (isCallable!fun &&
                                (functionAttributes!fun &
                                 FunctionAttribute.nogc));

  safe pure nothrow  nogc unittest
 {
     static int foo(int x)  nogc pure nothrow;
     static int goo(int x) pure nothrow;
     static assert(isNogc!foo);
     static assert(!isNogc!goo);
 }

 Seems to be working fine. I'd go with this version for perhaps 
 a bit more brevity and clarity:

 enum bool isNogc(alias fun) = hasFunctionAttributes!(fun, 
 " nogc");

 Both functionAttributes and hasFunctionAttributes already check 
 that the argument is a callable (which function attributes 
 should "foo" have?), so that's unnecessary.

 --
   Simen

Author of hasFunctionAttributes here.

FYI: `hasFunctionAttributes` is exactly intended to be used how 
you do it. functionAttributes is only there for legacy reasons.
And it works nicely with inference too:

https://run.dlang.io/is/9OXZct