• Henning Pohl (10/10) Aug 11 2012 So the struct is defined as:
• Jakob Ovrum (10/20) Aug 11 2012 struct S(T) {}
• Chris Cain (12/21) Aug 11 2012 Same idea, but doing it with just one template and using static
• Henning Pohl (2/13) Aug 11 2012 Thank you two. Did not know about the great abilities of is.
• Jakob Ovrum (6/17) Aug 11 2012 I usually prefer overloading for this particular kind of template

"Henning Pohl" <henning still-hidden.de> writes:

So the struct is defined as:

struct S(T) {
}

template isS(T) {
     // ...
}

static assert(isS(S!float));
static assert(!isS(float));

There may be some nasty ways using fullQualifiedName!T and so on 
but I guess there is a better way, isn't it?

"Jakob Ovrum" <jakobovrum gmail.com> writes:

On Saturday, 11 August 2012 at 18:51:36 UTC, Henning Pohl wrote:
 So the struct is defined as:

 struct S(T) {
 }

 template isS(T) {
     // ...
 }

 static assert(isS(S!float));
 static assert(!isS(float));

 There may be some nasty ways using fullQualifiedName!T and so 
 on but I guess there is a better way, isn't it?

struct S(T) {}

template isS(T : S!U, U) {
     enum isS = true;
}

template isS(T) {
     enum isS = false;
}

static assert(isS!(S!float));
static assert(!isS!float);

"Chris Cain" <clcain uncg.edu> writes:

On Saturday, 11 August 2012 at 18:56:30 UTC, Jakob Ovrum wrote:
 struct S(T) {}

 template isS(T : S!U, U) {
     enum isS = true;
 }

 template isS(T) {
     enum isS = false;
 }

 static assert(isS!(S!float));
 static assert(!isS!float);

Same idea, but doing it with just one template and using static 
ifs...

struct S(T) {}

template isS(T) {
     static if(is(T _ : S!U, U))
         enum isS = true;
     else
         enum isS = false;
}

static assert(isS!(S!float));
static assert(!isS!float);

"Henning Pohl" <henning still-hidden.de> writes:

On Saturday, 11 August 2012 at 19:06:22 UTC, Chris Cain wrote:
 Same idea, but doing it with just one template and using static 
 ifs...

 struct S(T) {}

 template isS(T) {
     static if(is(T _ : S!U, U))
         enum isS = true;
     else
         enum isS = false;
 }

 static assert(isS!(S!float));
 static assert(!isS!float);

Thank you two. Did not know about the great abilities of is.

"Jakob Ovrum" <jakobovrum gmail.com> writes:

On Saturday, 11 August 2012 at 19:06:22 UTC, Chris Cain wrote:
 Same idea, but doing it with just one template and using static 
 ifs...

 struct S(T) {}

 template isS(T) {
     static if(is(T _ : S!U, U))
         enum isS = true;
     else
         enum isS = false;
 }

 static assert(isS!(S!float));
 static assert(!isS!float);

I usually prefer overloading for this particular kind of template 
because of the restriction that is() expressions may only 
introduce symbols when used in static-if statements. I think the 
if(blah) a = true; else a = false; pattern is worth avoiding as 
it leaves a bad taste in the mouth of many programmers.