Template argument deduction from a function call question

[Ali Çehreli via Digitalmars-d]

On 04/01/2015 11:15 AM, John Colvin wrote:

 >> Instead of using
 >> ElementType!S in the parameter list, introduce a third one (E), which
 >> you check in the template constraint:
 >>
 >> ElementType!S aggregate(alias func, S, E)(S list, E accum = E.init)
 >> if(is (E == ElementType!S) &&                   // <-- ADDED
 >>     is(typeof(func(accum, accum)) == typeof(accum))) {
 >>         // ...
 >> }
 >>
 >> Now it works.
 >>
 >> Ali
 >
 > Great tip. Is that in your book somewhere?

I don't think so; not that one... (Noted though; I may get to it.)

I had carefully tried to avoid adding "too much" information. However, 
as the book progressed added more and more information like that, 
especially after Luís Marques's recommendations. I am very grateful for 
the effort he has put into reviewing and editing the book.

Ali