Re: Single type of a tuple return type function

[Vino via Digitalmars-d-learn]

On Thursday, 4 January 2018 at 16:09:07 UTC, Simen Kjærås wrote:

On Thursday, 4 January 2018 at 15:50:35 UTC, Vino wrote:

[...]


ReturnType!Fn[0] tries to give you the 0th field of the tuple, 
but as the error message indicates, you can't do that without 
an instance. What you want is the *type* of the field, as given 
by typeof:


typeof(ReturnType!Fn[0]) Dcol;

This can be made a bit simpler by noticing that ReturnType is 
unnecessary here:


typeof(Fn()[0]) Dcol;

However, if Fn() takes a bunch of complex parameters, this 
might not actually be simpler.


--
  Simen


HI Simen,

 Thank you very much, your solution was helpful.

From,
Vino.B

Re: Single type of a tuple return type function

[Simen Kjærås via Digitalmars-d-learn]

On Thursday, 4 January 2018 at 15:50:35 UTC, Vino wrote:

Hi All,

  Request your help, on how o find the single type of a tuple 
return type function, eg,


auto Fn (){
Array!string a;
Array!int b;
Array!ulong c;
return tuple(a, b, c);
}

if we use "ReturnType!Fn" it gives us the output as 
(Array!string,Array!int, Array!ulong) but what is need is the 
return type of  each of the value as

a = Array!string; b = Array!int; c = Array!ulong

void main () {
ReturnType!Fn[0] Dcol;  //similar like this line
writeln(Dcol[]);
}

From,
Vino.B


ReturnType!Fn[0] tries to give you the 0th field of the tuple, 
but as the error message indicates, you can't do that without an 
instance. What you want is the *type* of the field, as given by 
typeof:


typeof(ReturnType!Fn[0]) Dcol;

This can be made a bit simpler by noticing that ReturnType is 
unnecessary here:


typeof(Fn()[0]) Dcol;

However, if Fn() takes a bunch of complex parameters, this might 
not actually be simpler.


--
  Simen

Single type of a tuple return type function

[Vino via Digitalmars-d-learn]

Hi All,

  Request your help, on how o find the single type of a tuple 
return type function, eg,


auto Fn (){
Array!string a;
Array!int b;
Array!ulong c;
return tuple(a, b, c);
}

if we use "ReturnType!Fn" it gives us the output as 
(Array!string,Array!int, Array!ulong) but what is need is the 
return type of  each of the value as

a = Array!string; b = Array!int; c = Array!ulong

void main () {
ReturnType!Fn[0] Dcol;  //similar like this line
writeln(Dcol[]);
}

From,
Vino.B