• Rory McGuire (11/11) Aug 29 2013 Hi all,
• Rory McGuire (16/27) Aug 29 2013 forum posted when I hit tab. Meant to ask:
• Rory McGuire (5/34) Aug 30 2013 I suppose I can avoid the implicit casts for function lookup by

"Rory McGuire" <rjmcguire gmail.com> writes:

Hi all,

I've got this little ctfe template function that checks if a 
function called member with first argument T exists. Its for 
checking if a type has a custom encoder.

bool hasUFCSmember(T, string member)() {
	T v;
	// would be nice if we could use ParameterTypeTuple to get the 
first arg and check for exact type match
	
	return __traits(compiles, mixin(member ~"(v)"));
}

"Rory McGuire" <rjmcguire gmail.com> writes:

On Thursday, 29 August 2013 at 21:06:04 UTC, Rory McGuire wrote:
 Hi all,

 I've got this little ctfe template function that checks if a 
 function called member with first argument T exists. Its for 
 checking if a type has a custom encoder.

 bool hasUFCSmember(T, string member)() {
 	T v;
 	// would be nice if we could use ParameterTypeTuple to get the 
 first arg and check for exact type match
 	
 	return __traits(compiles, mixin(member ~"(v)"));
 }

forum posted when I hit tab. Meant to ask:

Is there a way to make sure that the compiler is not implicitly 
casting T?
Currently it returns true for bool, enum, int etc... even if the 
only function available is for an int.

I also have:
template hasUFCSmember(T, string member) {
	 enum hasUFCSmember = __traits(compiles, mixin(member 
~"(T.init)"));
}
But it doesn't work for types such as string[string] because 
T.init is null.

Any help will be greatly appreciated.

Thanks,
R

"Rory McGuire" <rjmcguire gmail.com> writes:

On Thursday, 29 August 2013 at 21:10:41 UTC, Rory McGuire wrote:
 On Thursday, 29 August 2013 at 21:06:04 UTC, Rory McGuire wrote:
 Hi all,

 I've got this little ctfe template function that checks if a 
 function called member with first argument T exists. Its for 
 checking if a type has a custom encoder.

 bool hasUFCSmember(T, string member)() {
 	T v;
 	// would be nice if we could use ParameterTypeTuple to get 
 the first arg and check for exact type match
 	
 	return __traits(compiles, mixin(member ~"(v)"));
 }

 forum posted when I hit tab. Meant to ask:

 Is there a way to make sure that the compiler is not implicitly 
 casting T?
 Currently it returns true for bool, enum, int etc... even if 
 the only function available is for an int.

 I also have:
 template hasUFCSmember(T, string member) {
 	 enum hasUFCSmember = __traits(compiles, mixin(member 
 ~"(T.init)"));
 }
 But it doesn't work for types such as string[string] because 
 T.init is null.

 Any help will be greatly appreciated.

 Thanks,
 R

I suppose I can avoid the implicit casts for function lookup by 
using Typedef.

Thanks,
R