Traits

[Agustin]

On Friday, 11 October 2013 at 19:19:31 UTC, luminousone wrote:
> On Friday, 11 October 2013 at 14:09:09 UTC, Gary Willoughby 
> wrote:
>> On Friday, 11 October 2013 at 05:49:38 UTC, luminousone wrote:
>>> On Friday, 11 October 2013 at 04:13:55 UTC, Agustin wrote:
>>>> I have a function that needs to check if the template 
>>>> provided inherit a class.
>>>>
>>>> For example:
>>>>
>>>> public void function(T, A...)(auto ref A values)
>>>> {
>>>> // static assert(IsBaseOf(L, T));
>>>> }
>>>>
>>>> Check if T inherit class "L". Same result that 
>>>> std::is_base_of<L, T>::value using C++. Any clean way to do 
>>>> it, without a dirty hack.
>>>
>>> import std.traits;
>>>
>>> bool ChildInheritsFromParent( parent, child )( ) {
>>> 	
>>> 	foreach ( k, t; BaseClassesTuple!child ) {
>>> 		if( typeid(t) == typeid(parent) )
>>> 			return true;
>>> 	}
>>> 	return false;
>>> }
>>
>> A simpler way:
>>
>> 	import std.stdio;
>>
>> 	bool instanceOf(A, B)(B value)
>> 	{
>> 		return !!cast(A)value;
>> 	}
>>
>> 	void main()
>> 	{
>> 		assert(1.instanceOf!(int));
>> 	}
>
> Using casts that way won't always be correct, it would be 
> better to use reflection in some way if possible.

This is wrong for me because i don't have a value, i just wanted 
to check if a template parameter inherit a class at compile time.

bool instanceOf(A, B)();