On Tuesday, 26 August 2025 at 20:04:36 UTC, monkyyy wrote:
does anyone how a concept for insideout iterating
I have this:
```d
struct cursor(T){
T[] data; alias data this;
int index;
ref opIndex(int i){
return data[min($-1,max(0,i+index))];
}
auto forward(){
struct range{
T[] data;
int index;
ref T front()=>data[0];
void popFront(){
data=data[1..$];
index++;
}
bool empty()=>data.length==0;
}
return range(data[index..$],0);
}
auto back(){
struct range{
T[] data;
int index;
ref T front()=>data[$-1];
void popFront(){
data=data[0..$-1];
index--;
}
bool empty()=>data.length==0;
}
return range(data[0..index],-1);
}
auto forwardthenback()=>chain(forward,back);
}
```
and Im using [index-sign(index)] to access the reliant other
member surely theres a better way
---
```d
foreach(ref me,ref other;[1,2,3,4,5].???(2)){
writeln(me,','other);
}
```
```
3,3
4,3
5,4
2,3
1,2
```
(reminder tuples and refness dont actaully work, and im
modifying the center out)
```d
#!opend -unittest -main -run app.d
import std;
auto insideout(R,I)(R r,I i){
struct foreach_{
R r;
I i;
alias E=typeof(r[i]);
int opApply(int delegate(ref E a,ref E b) dg){
int result=dg(r[i],r[i]);
I j=i+1;
if(result>1) {goto exit;}
while(j<r.length){
result=dg(r[j],r[j-1]);
if(result){
if(result==1){break;}
goto exit;
}
j++;
}
j=i-1;
while(j>=0){
result=dg(r[j],r[j+1]);
if(result){
break;
}
j--;
}
exit:return result;
}
}
return foreach_(r,i);
}
unittest{
lable: foreach(ref me,ref other;[1,2,3,4,5,6,7,8].insideout(2)){
writeln(me,',',other);
if(me==5){break;}
}
"end".writeln;
}
```
