Re: Checking if UFCS function exists for a specific type

[Rory McGuire]

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

Checking if UFCS function exists for a specific type

[Rory McGuire]

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)));
}

Re: Checking if UFCS function exists for a specific type

[Rory McGuire]

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