Fallback 'catch-all' template functions

[Manu via Digitalmars-d]

On 3 September 2016 at 19:19, Walter Bright via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
> On 8/31/2016 10:37 PM, Manu via Digitalmars-d wrote:
>>
>> So, consider a set of overloads:
>>
>>   void f(T)(T t) if(isSomething!T) {}
>>   void f(T)(T t) if(isSomethingElse!T) {}
>>   void f(T)(T t) {}
>>
>> I have a recurring problem where I need a fallback function like the
>> bottom one, which should be used in lieu of a more precise match.
>> This is obviously an ambiguous call, but this is a pattern that comes
>> up an awful lot. How to do it in D?
>
>
>
> import core.stdc.stdio;
>
> void f(T:T)(T t) if(is(T == int)) { printf("case int\n"); }
> void f(T:T)(T t) if(is(T == uint)) { printf("case uint\n"); }
> void f(T)(T t) { printf("case default\n"); }
>
> void main()
> {
>     f(1);
>     f(1u);
>     f(1.0);
> }
>
> ----
> A bit odd, but far better than SFINAE.

This is interesting. Can you explain how that works?