On Thursday, 15 July 2021 at 15:39:59 UTC, Tejas wrote:
On Thursday, 15 July 2021 at 13:28:19 UTC, wjoe wrote:
On Thursday, 15 July 2021 at 12:09:20 UTC, Tejas wrote:
[...]
The only way, for me, to explain the error message ```opIndex
isn't an lvalue and can't be modified.``` for
On Thursday, 15 July 2021 at 13:28:19 UTC, wjoe wrote:
On Thursday, 15 July 2021 at 12:09:20 UTC, Tejas wrote:
[...]
The only way, for me, to explain the error message ```opIndex
isn't an lvalue and can't be modified.``` for ```i[1]++``` is
that the compiler rewrites to
```D
(auto e =
On Thursday, 15 July 2021 at 12:09:20 UTC, Tejas wrote:
[...]
Oh yes, that is what happens. I was trying to be a little
concise.
You are correct, this is what the code will look in the gory
details (I believe) :
```d
auto x = (auto e = i.opIndex(1), i.opIndexUnary("++")(1)/*this
may or may
On Thursday, 15 July 2021 at 11:02:17 UTC, wjoe wrote:
On Thursday, 15 July 2021 at 04:07:49 UTC, Tejas wrote:
Your code
```d
auto x = i[1]++;
```
Expands to:
```d
auto x = (auto e = i[1]/*notice opIndex*/, ++i[1]/* notice
opIndexUnary*/, return e;);
```
This doesn't happen with pre
On Thursday, 15 July 2021 at 04:07:49 UTC, Tejas wrote:
Your code
```d
auto x = i[1]++;
```
Expands to:
```d
auto x = (auto e = i[1]/*notice opIndex*/, ++i[1]/* notice
opIndexUnary*/, return e;);
```
This doesn't happen with pre increment. No compiler shenanigans.
Interesting to see it
On Thursday, 15 July 2021 at 04:01:15 UTC, Tejas wrote:
I'm so sorry all this was basically useless for you.
I can't spend more time on this, so as a last resort I leave
you this:
https://dlang.org/phobos/std_bitmanip.html
This is the official bit manipulation standard library, maybe
it
On Wednesday, 14 July 2021 at 20:55:32 UTC, wjoe wrote:
In my particular case the compiler can rule out ```opIndex```
so why does it abort instead of trying ```opIndexUnary``` ? Or
was it trying and it didn't work ? If that's the case I'd like
to know the reason why it discarded
On Wednesday, 14 July 2021 at 20:55:32 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 16:13:35 UTC, Tejas wrote:
[...]
Congratulations:) Unfortunately I haven't got anything I could
return by ref so I can't take advantage of a low hanging fruit.
In my book overloading operators is no fun -
On Wednesday, 14 July 2021 at 16:13:35 UTC, Tejas wrote:
On Wednesday, 14 July 2021 at 15:08:56 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 14:50:01 UTC, Mike Parker wrote:
On Wednesday, 14 July 2021 at 12:35:07 UTC, wjoe wrote:
[...]
It's how the contract of post-inc/dec
On 7/14/21 11:27 AM, Tejas wrote:
> the compiler error should have been a dead giveaway
> that opIndex was returning a _constant_ value
I know you mean "rvalue" but if I may be unnecessarily pedantic, an
rvalue can indeed be mutated:
struct A {
int i;
void mutate() {
i = 42;
On Wednesday, 14 July 2021 at 17:42:03 UTC, Ali Çehreli wrote:
On 7/14/21 9:13 AM, Tejas wrote:
> ref/*notice this ref*/ int opIndex(int
index)return/*NOTICE THE
> RETURN*/ {
Indeed... I cover that 'ref' here:
On 7/14/21 9:13 AM, Tejas wrote:
> ref/*notice this ref*/ int opIndex(int index)return/*NOTICE THE
> RETURN*/ {
Indeed... I cover that 'ref' here:
http://ddili.org/ders/d.en/operator_overloading.html#ix_operator_overloading.return%20type,%20operator
Two quotes from that section:
1) "it
On Wednesday, 14 July 2021 at 15:08:56 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 14:50:01 UTC, Mike Parker wrote:
On Wednesday, 14 July 2021 at 12:35:07 UTC, wjoe wrote:
[...]
It's how the contract of post-inc/dec work---pre-inc/dec
return the modified value, post-inc/dec return the
On Wednesday, 14 July 2021 at 15:23:05 UTC, vit wrote:
On Wednesday, 14 July 2021 at 15:19:03 UTC, vit wrote:
```d
import std.stdio;
struct abc{
int[100] a;
struct Proxy{
abc* ptr;
const int index;
int opUnary(string op : "++")(){
return
On Wednesday, 14 July 2021 at 15:23:05 UTC, vit wrote:
On Wednesday, 14 July 2021 at 15:19:03 UTC, vit wrote:
```d
import std.stdio;
struct abc{
int[100] a;
struct Proxy{
abc* ptr;
const int index;
int opUnary(string op : "++")(){
return
On Wednesday, 14 July 2021 at 15:19:03 UTC, vit wrote:
```d
import std.stdio;
struct abc{
int[100] a;
struct Proxy{
abc* ptr;
const int index;
int opUnary(string op : "++")(){
return ++ptr.a[index]; //add missing ++
}
}
On Wednesday, 14 July 2021 at 14:39:03 UTC, vit wrote:
On Wednesday, 14 July 2021 at 13:16:49 UTC, Tejas wrote:
On Wednesday, 14 July 2021 at 13:09:56 UTC, vit wrote:
On Wednesday, 14 July 2021 at 12:49:58 UTC, Tejas wrote:
[...]
From doc: https://dlang.org/spec/operatoroverloading.html
On Wednesday, 14 July 2021 at 15:01:45 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 14:39:03 UTC, vit wrote:
On Wednesday, 14 July 2021 at 13:16:49 UTC, Tejas wrote:
[...]
This work:
```d
import std.stdio;
struct abc{
int[100] a;
ref int opIndex(int index)return{
On Wednesday, 14 July 2021 at 14:50:01 UTC, Mike Parker wrote:
On Wednesday, 14 July 2021 at 12:35:07 UTC, wjoe wrote:
[...]
It's how the contract of post-inc/dec work---pre-inc/dec return
the modified value, post-inc/dec return the original value.
[...]
That makes a lot of sense now,
On Wednesday, 14 July 2021 at 14:39:03 UTC, vit wrote:
On Wednesday, 14 July 2021 at 13:16:49 UTC, Tejas wrote:
On Wednesday, 14 July 2021 at 13:09:56 UTC, vit wrote:
On Wednesday, 14 July 2021 at 12:49:58 UTC, Tejas wrote:
[...]
From doc: https://dlang.org/spec/operatoroverloading.html
On Wednesday, 14 July 2021 at 12:35:07 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 11:31:36 UTC, Tejas wrote:
``` {auto a = i[1] , ++i[1] , a} //note the , not the ;```
Sorry I can't provide something even more concrete.
Yes I saw that, and I suppose it would work just fine if it
were
On Wednesday, 14 July 2021 at 12:49:58 UTC, Tejas wrote:
I think it's a bug, because the following works:
```d
import std.stdio;
struct abc{
int[100] a;
int opIndex(int index){
return a[index];
}
int opIndexUnary(string s)(int index)
if(s == "++"){
On Wednesday, 14 July 2021 at 13:16:49 UTC, Tejas wrote:
On Wednesday, 14 July 2021 at 13:09:56 UTC, vit wrote:
On Wednesday, 14 July 2021 at 12:49:58 UTC, Tejas wrote:
[...]
From doc: https://dlang.org/spec/operatoroverloading.html
Postincrement e++ and Postdecrement e-- Operators
These are
On Wednesday, 14 July 2021 at 13:09:56 UTC, vit wrote:
On Wednesday, 14 July 2021 at 12:49:58 UTC, Tejas wrote:
On Wednesday, 14 July 2021 at 12:35:07 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 11:31:36 UTC, Tejas wrote:
``` {auto a = i[1] , ++i[1] , a} //note the , not the ;```
Sorry I
On Wednesday, 14 July 2021 at 12:49:58 UTC, Tejas wrote:
On Wednesday, 14 July 2021 at 12:35:07 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 11:31:36 UTC, Tejas wrote:
``` {auto a = i[1] , ++i[1] , a} //note the , not the ;```
Sorry I can't provide something even more concrete.
Yes I saw
On Wednesday, 14 July 2021 at 11:31:36 UTC, Tejas wrote:
On Wednesday, 14 July 2021 at 10:07:38 UTC, wjoe wrote:
I'm want to do something like this
```D
part_int_t!(1,2,3) i;
auto x = -i[0];
--i[1]; // 1
i[1]++; // 2
```
I think the operator I need to overload would be opIndexUnary
which I
On Wednesday, 14 July 2021 at 12:35:07 UTC, wjoe wrote:
On Wednesday, 14 July 2021 at 11:31:36 UTC, Tejas wrote:
``` {auto a = i[1] , ++i[1] , a} //note the , not the ;```
Sorry I can't provide something even more concrete.
Yes I saw that, and I suppose it would work just fine if it
were
On Wednesday, 14 July 2021 at 11:31:36 UTC, Tejas wrote:
``` {auto a = i[1] , ++i[1] , a} //note the , not the ;```
Sorry I can't provide something even more concrete.
Yes I saw that, and I suppose it would work just fine if it were
rewritten to just ```++i[1]```.
What I'm struggling to
On Wednesday, 14 July 2021 at 10:07:38 UTC, wjoe wrote:
I'm want to do something like this
```D
part_int_t!(1,2,3) i;
auto x = -i[0];
--i[1]; // 1
i[1]++; // 2
```
I think the operator I need to overload would be opIndexUnary
which I did.
(1) compiles.
(2) doesn't - the compiler complains
I'm want to do something like this
```D
part_int_t!(1,2,3) i;
auto x = -i[0];
--i[1]; // 1
i[1]++; // 2
```
I think the operator I need to overload would be opIndexUnary
which I did.
(1) compiles.
(2) doesn't - the compiler complains that i.opIndex isn't an
lvalue and can't be modified.
The
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