Understanding Templates: why can't anybody do it?

[Walter Bright]

On 3/17/2012 10:55 AM, Andrei Alexandrescu wrote:
> On 3/17/12 12:14 PM, Entity325 wrote:
>> Who's with me? Anybody have a short(but COMPLETE!) example of code that
>> makes use of Templates that you actually understand what's going on there?
>
> You're on to something here. Then, as usual, from idea to realization there are
> quite a few steps.
>
> I took a complementary approach in TDPL: there's no chapter on templates at all.
> Templates are naturally interwoven with whatever topic is at hand, wherever
> they're useful. I hoped people would learn templates without even knowing it.

Sans value parameters:

  int foo() {
     return 3;
  }

With value parameters:

   int foo(int i) {
     return i;
   }

Sans type parameters:

  struct S {
    int i;
  }

With type parameters:

  struct S(T) {
    T i;
  }

i.e. templates are type parameters.