http://www.reddit.com/r/programming/comments/335b1s/the_new_operator_in_c_6/

of interesting note was the nim sample on how to implement the same thing in nim in 2 lines of code

template `?.`(a, b): expr =
  if a != nil: a.b else: nil

template `??`(a, b): expr =
  if a != nil: a else: b

On Monday, 20 April 2015 at 08:24:08 UTC, weaselcat wrote:
> http://www.reddit.com/r/programming/comments/335b1s/the_new_operator_in_c_6/
>
> of interesting note was the nim sample on how to implement the same thing in nim in 2 lines of code
>
> template `?.`(a, b): expr =
>   if a != nil: a.b else: nil
>
> template `??`(a, b): expr =
>   if a != nil: a else: b

This is what I came up with for D:

    https://gist.github.com/JakobOvrum/7e3a7bc130ab7db28de3

Meh.

On Monday, 20 April 2015 at 08:24:08 UTC, weaselcat wrote:
> http://www.reddit.com/r/programming/comments/335b1s/the_new_operator_in_c_6/
>
> of interesting note was the nim sample on how to implement the same thing in nim in 2 lines of code
>
> template `?.`(a, b): expr =
>   if a != nil: a.b else: nil
>
> template `??`(a, b): expr =
>   if a != nil: a else: b

HS Teoh came up with a beautiful solution using opDispatch, but I can't find the thread right now. That also reminds me that I meant to make a PR for it and completely forgot.

On Monday, 20 April 2015 at 12:16:21 UTC, Jakob Ovrum wrote:
> On Monday, 20 April 2015 at 08:24:08 UTC, weaselcat wrote:
>> http://www.reddit.com/r/programming/comments/335b1s/the_new_operator_in_c_6/
>>
>> of interesting note was the nim sample on how to implement the same thing in nim in 2 lines of code
>>
>> template `?.`(a, b): expr =
>>  if a != nil: a.b else: nil
>>
>> template `??`(a, b): expr =
>>  if a != nil: a else: b
>
> This is what I came up with for D:
>
>     https://gist.github.com/JakobOvrum/7e3a7bc130ab7db28de3
>
> Meh.

Here's mine:

https://gist.github.com/atilaneves/727d63f0a7029032d7ac

On Monday, 20 April 2015 at 15:37:02 UTC, Atila Neves wrote:
> On Monday, 20 April 2015 at 12:16:21 UTC, Jakob Ovrum wrote:
>> On Monday, 20 April 2015 at 08:24:08 UTC, weaselcat wrote:
>>> http://www.reddit.com/r/programming/comments/335b1s/the_new_operator_in_c_6/
>>>
>>> of interesting note was the nim sample on how to implement the same thing in nim in 2 lines of code
>>>
>>> template `?.`(a, b): expr =
>>> if a != nil: a.b else: nil
>>>
>>> template `??`(a, b): expr =
>>> if a != nil: a else: b
>>
>> This is what I came up with for D:
>>
>>    https://gist.github.com/JakobOvrum/7e3a7bc130ab7db28de3
>>
>> Meh.
>
> Here's mine:
>
> https://gist.github.com/atilaneves/727d63f0a7029032d7ac


I fail to understand Atila example. Just to be sure:

C#:
var roleName = userManager.CurrentUser?.GetRole()?.Name;

D (Jakob):
auto roleName = userManager.getOrNull!("CurrentUser", "GetRole", "Name");

D (Atila):
auto roleName = ?

On Monday, 20 April 2015 at 14:19:06 UTC, Meta wrote:
> On Monday, 20 April 2015 at 08:24:08 UTC, weaselcat wrote:
>> http://www.reddit.com/r/programming/comments/335b1s/the_new_operator_in_c_6/
>>
>> of interesting note was the nim sample on how to implement the same thing in nim in 2 lines of code
>>
>> template `?.`(a, b): expr =
>>  if a != nil: a.b else: nil
>>
>> template `??`(a, b): expr =
>>  if a != nil: a else: b
>
> HS Teoh came up with a beautiful solution using opDispatch, but I can't find the thread right now. That also reminds me that I meant to make a PR for it and completely forgot.

http://forum.dlang.org/thread/lnsc0c$1sip$1@digitalmars.com?page=6#post-mailman.2584.1403213951.2907.digitalmars-d:40puremagic.com

On Monday, 20 April 2015 at 20:09:59 UTC, rumbu wrote:
> On Monday, 20 April 2015 at 15:37:02 UTC, Atila Neves wrote:
>> On Monday, 20 April 2015 at 12:16:21 UTC, Jakob Ovrum wrote:
>>> On Monday, 20 April 2015 at 08:24:08 UTC, weaselcat wrote:
>>>> http://www.reddit.com/r/programming/comments/335b1s/the_new_operator_in_c_6/
>>>>
>>>> of interesting note was the nim sample on how to implement the same thing in nim in 2 lines of code
>>>>
>>>> template `?.`(a, b): expr =
>>>> if a != nil: a.b else: nil
>>>>
>>>> template `??`(a, b): expr =
>>>> if a != nil: a else: b
>>>
>>> This is what I came up with for D:
>>>
>>>   https://gist.github.com/JakobOvrum/7e3a7bc130ab7db28de3
>>>
>>> Meh.
>>
>> Here's mine:
>>
>> https://gist.github.com/atilaneves/727d63f0a7029032d7ac
>
>
> I fail to understand Atila example. Just to be sure:
>
> C#:
> var roleName = userManager.CurrentUser?.GetRole()?.Name;
>
> D (Jakob):
> auto roleName = userManager.getOrNull!("CurrentUser", "GetRole", "Name");
>
> D (Atila):
> auto roleName = ?

These API look overly complex. Why not simply:

maybe(userManager).CurrentUser.GetRole().Name ?

Also, CAPITAL LETTER ARE THE BEST !

On Monday, 20 April 2015 at 21:22:53 UTC, deadalnix wrote:
> On Monday, 20 April 2015 at 20:09:59 UTC, rumbu wrote:
..
>>
>>
>> I fail to understand Atila example. Just to be sure:
>>
>> C#:
>> var roleName = userManager.CurrentUser?.GetRole()?.Name;
>>
>> D (Jakob):
>> auto roleName = userManager.getOrNull!("CurrentUser", "GetRole", "Name");
>>
>> D (Atila):
>> auto roleName = ?
>
> These API look overly complex. Why not simply:
>
> maybe(userManager).CurrentUser.GetRole().Name ?
>
> Also, CAPITAL LETTER ARE THE BEST !

Because CurrentUser, GetRole() and Name can also return null in this scenario.

On 04/20/2015 03:18 PM, rumbu wrote:
> On Monday, 20 April 2015 at 21:22:53 UTC, deadalnix wrote:
>> On Monday, 20 April 2015 at 20:09:59 UTC, rumbu wrote:
> ..
>>>
>>>
>>> I fail to understand Atila example. Just to be sure:
>>>
>>> C#:
>>> var roleName = userManager.CurrentUser?.GetRole()?.Name;
>>>
>>> D (Jakob):
>>> auto roleName = userManager.getOrNull!("CurrentUser", "GetRole",
>>> "Name");
>>>
>>> D (Atila):
>>> auto roleName = ?
>>
>> These API look overly complex. Why not simply:
>>
>> maybe(userManager).CurrentUser.GetRole().Name ?
>>
>> Also, CAPITAL LETTER ARE THE BEST !
>
> Because CurrentUser, GetRole() and Name can also return null in this
> scenario.
>

The solution linked elsewhere in this thread solves that issue as well:


http://forum.dlang.org/thread/lnsc0c$1sip$1@digitalmars.com?page=6#post-mailman.2584.1403213951.2907.digitalmars-d:40puremagic.com

Ali

On Monday, 20 April 2015 at 22:18:31 UTC, rumbu wrote:
> On Monday, 20 April 2015 at 21:22:53 UTC, deadalnix wrote:
>> On Monday, 20 April 2015 at 20:09:59 UTC, rumbu wrote:
> ..
>>>
>>>
>>> I fail to understand Atila example. Just to be sure:
>>>
>>> C#:
>>> var roleName = userManager.CurrentUser?.GetRole()?.Name;
>>>
>>> D (Jakob):
>>> auto roleName = userManager.getOrNull!("CurrentUser", "GetRole", "Name");
>>>
>>> D (Atila):
>>> auto roleName = ?
>>
>> These API look overly complex. Why not simply:
>>
>> maybe(userManager).CurrentUser.GetRole().Name ?
>>
>> Also, CAPITAL LETTER ARE THE BEST !
>
> Because CurrentUser, GetRole() and Name can also return null in this scenario.

No, they all return a maybe, that is the nature of maybe monad.