• simendsjo <simendsjo gmail.com> Mar 31 2012
• James Miller <james aatch.net> Apr 01 2012

simendsjo <simendsjo gmail.com> writes:

Is is possible to use UFCS for types to simulate static members?

struct S {
     static void f();
}

void ext(S)() {
     S.f();
}

void main() {
     ext!S(); // ok
     S.ext(); // Error: no property 'ext' for type 'S'
}

James Miller <james aatch.net> writes:

On 31 March 2012 21:37, simendsjo <simendsjo gmail.com> wrote:
 Is is possible to use UFCS for types to simulate static members?

 struct S {
 =C2=A0 =C2=A0static void f();
 }

 void ext(S)() {
 =C2=A0 =C2=A0S.f();
 }

 void main() {
 =C2=A0 =C2=A0ext!S(); // ok
 =C2=A0 =C2=A0S.ext(); // Error: no property 'ext' for type 'S'
 }


As far as I know UFCS just rewrites `a.f(b,c)` to `f(a,b,c)`, so
probably not, since `S.ext()` would be re-written to `ext(S)`, which
obviously makes no sense. Its pretty much just syntatic sugar with a
few disambiguation rules.

Basically you're asking for UFCS for template parameters, but that
would introduce too many ambiguities, especially considering things
like alias parameters:

    ext(alias T, U)(U a);
    int foo =3D 1;
    foo.ext() //does the alias T get the value, or the U a?

If you just remember that UFCS is just for functions, not templates,
or rather its Uniform Function-Call Syntax, not Uniform
Template-Instantiation Syntax (UTIS?). Because even ext(T)(); is just
sugar for:

    template ext(T) {
       void ext();
    }

--
James Miller