On Wednesday, 24 September 2025 at 00:12:40 UTC, monkyyy wrote:
> ```d
> import std;
> struct sumrange(E){
> //void* me;
> //TypeInfo meta;
> E delegate() front_;
> E front()=>front_();
> void delegate() popFront_;
> void popFront()=>popFront_();
> bool delegate() empty_;
> bool empty()=>empty_();
> void opAssign(T)(ref T t){
> //me=cast(void*)&t;
> static assert(is(typeof(t.front())==E));
> front_=cast(E delegate())&t.front;
> popFront_=cast(void delegate())&t.popFront;
> empty_=cast(bool delegate())&t.empty;
> }
> }
>
> unittest{
> sumrange!int foo;
> auto bar=iota(int(10));
> foo=bar;
> foreach(i;foo){
> i.writeln;
> }
> auto bar2=[1,2,3].map!(a=>a);
> foo=bar2;
> foreach(i;foo){
> i.writeln;
> }
> auto bar3=only(1);
> foo=bar3;
> foreach(i;foo){
> i.writeln;
> }
> //foo=iota(10.0);//Error: static assert: `is(double == int)`
> is false
> }
> ```
`std.range.interfaces` already does this:
```d
import std.range.interfaces;
import std.range;
import std.algorithm;
import std.stdio;
void main()
{
InputRange!int foo;
auto bar1 = iota(10);
foo = bar1.inputRangeObject;
foreach (i; foo)
writeln(i);
auto bar2 = [1, 2, 3].map!(a => a);
foo = bar2.inputRangeObject;
foreach (i; foo)
writeln(i);
auto bar3 = only(1);
foo = bar3.inputRangeObject;
foreach (i; foo)
writeln(i);
}
```