• Luc Bourhis (24/24) Jan 14 2015 There is "isFloatingPointType!T" to find out whether type T is
• Luc Bourhis (2/2) Jan 14 2015 I forgot to mention the obvious: I simply parroted the code in
• John Colvin (4/28) Jan 14 2015 It doesn't answer your question as such, but you should take a
• Luc Bourhis (2/5) Jan 14 2015 The planned obsolescence of cdouble and consort is another issue

"Luc Bourhis" <ljbo nowhere.com> writes:

There is "isFloatingPointType!T" to find out whether type T is 
one of the floating point types but I could not find anything 
equivalent for complex numbers (cdouble, cfloat, creal) in Phobos 
2.066 (which I installed with MacPorts for the record). Am I 
missing something?

My goal was to detect types suitable as scalars in a linear 
algebra context. I had to do it by hand:

enum bool supportedScalar(T) = is(ScalarTypeOf!T) && 
!isAggregateType!T;

private {
   alias ScalarTypeList = TypeTuple!(float, double, real,
                                     cfloat, cdouble, creal);
   template ScalarTypeOf(T) {
       static if (is(AliasThisTypeOf!T AT) && !is(AT[] == AT))
           alias X = ScalarTypeOf!AT;
       else
           alias X = OriginalType!T;

       static if (staticIndexOf!(Unqual!X, ScalarTypeList) >= 0)
           alias ScalarTypeOf = X;
       else
           static assert(0, T.stringof~" is not a floating point 
type");
   }
}

"Luc Bourhis" <ljbo nowhere.com> writes:

I forgot to mention the obvious: I simply parroted the code in 
std.traits!

"John Colvin" <john.loughran.colvin gmail.com> writes:

On Wednesday, 14 January 2015 at 13:38:05 UTC, Luc Bourhis wrote:
 There is "isFloatingPointType!T" to find out whether type T is 
 one of the floating point types but I could not find anything 
 equivalent for complex numbers (cdouble, cfloat, creal) in 
 Phobos 2.066 (which I installed with MacPorts for the record). 
 Am I missing something?

 My goal was to detect types suitable as scalars in a linear 
 algebra context. I had to do it by hand:

 enum bool supportedScalar(T) = is(ScalarTypeOf!T) && 
 !isAggregateType!T;

 private {
   alias ScalarTypeList = TypeTuple!(float, double, real,
                                     cfloat, cdouble, creal);
   template ScalarTypeOf(T) {
       static if (is(AliasThisTypeOf!T AT) && !is(AT[] == AT))
           alias X = ScalarTypeOf!AT;
       else
           alias X = OriginalType!T;

       static if (staticIndexOf!(Unqual!X, ScalarTypeList) >= 0)
           alias ScalarTypeOf = X;
       else
           static assert(0, T.stringof~" is not a floating point 
 type");
   }
 }

It doesn't answer your question as such, but you should take a 
look at:
http://dlang.org/phobos/std_complex.html

"Luc Bourhis" <ljbo nowhere.com> writes:

 It doesn't answer your question as such, but you should take a 
 look at:
 http://dlang.org/phobos/std_complex.html

The planned obsolescence of cdouble and consort is another issue 
I wanted to raise actually but better do it in a dedicated thread.