Hi all,

In the source code, written in D, is often used in the design of the `for (;;) { ... }`

Maybe someone has specific examples of translation of code in asm, where `while (true) { ... }` or `for (;;) { ... }` affect the performance or cross-platform programs.
It would be interesting to see samples.

On Thursday, 24 November 2016 at 21:57:15 UTC, Dennis Ritchie wrote:
> Hi all,
>
> In the source code, written in D, is often used in the design of the `for (;;) { ... }`
>
> Maybe someone has specific examples of translation of code in asm, where `while (true) { ... }` or `for (;;) { ... }` affect the performance or cross-platform programs.
> It would be interesting to see samples.

As you can see [1] the `while (true)` is lowered into `for (;true;)` so it's all about what construct pleases you the most.

[1] https://github.com/dlang/dmd/blob/cd451ceae40d04f7371e46df1c955fd914f3085f/src/statementsem.d#L357

On Thursday, 24 November 2016 at 22:04:00 UTC, LiNbO3 wrote:
> As you can see [1] the `while (true)` is lowered into `for (;true;)` so it's all about what construct pleases you the most.
>
> [1] https://github.com/dlang/dmd/blob/cd451ceae40d04f7371e46df1c955fd914f3085f/src/statementsem.d#L357

OK, thanks.

The next question is:
What principles guided when choosing between `for (;;) { ... }` and `while (true) { ... }` ?

For example, there are two options:
https://github.com/dlang/phobos/blob/master/std/algorithm/sorting.d

On 11/24/2016 05:09 PM, Dennis Ritchie wrote:
> On Thursday, 24 November 2016 at 22:04:00 UTC, LiNbO3 wrote:
>> As you can see [1] the `while (true)` is lowered into `for (;true;)`
>> so it's all about what construct pleases you the most.
>>
>> [1]
>> https://github.com/dlang/dmd/blob/cd451ceae40d04f7371e46df1c955fd914f3085f/src/statementsem.d#L357
>>
>
> OK, thanks.
>
> The next question is:
> What principles guided when choosing between `for (;;) { ... }` and
> `while (true) { ... }` ?
>
> For example, there are two options:
> https://github.com/dlang/phobos/blob/master/std/algorithm/sorting.d

I wouldn't ding anyone in a code review for using one vs the other. -- Andrei

Why you consider only 2 options?
Use "do {} while (true);" :-)

On 25/11/2016 8:27 PM, unDEFER wrote:
> Why you consider only 2 options?
> Use "do {} while (true);" :-)

The condition only executes after a single iteration.
So it is not the same code flow.

On Friday, 25 November 2016 at 08:46:24 UTC, rikki cattermole wrote:
> On 25/11/2016 8:27 PM, unDEFER wrote:
>> Why you consider only 2 options?
>> Use "do {} while (true);" :-)
>
> The condition only executes after a single iteration.
> So it is not the same code flow.

For an the usecase infinite-loop the code has the same effect.
And will translate to the same machine-code, hopefully.

On Thursday, 24 November 2016 at 22:09:22 UTC, Dennis Ritchie wrote:
> On Thursday, 24 November 2016 at 22:04:00 UTC, LiNbO3 wrote:
>> As you can see [1] the `while (true)` is lowered into `for (;true;)` so it's all about what construct pleases you the most.
>>
>> [1] https://github.com/dlang/dmd/blob/cd451ceae40d04f7371e46df1c955fd914f3085f/src/statementsem.d#L357
>
> OK, thanks.
>
> The next question is:
> What principles guided when choosing between `for (;;) { ... }` and `while (true) { ... }` ?
>
> For example, there are two options:
> https://github.com/dlang/phobos/blob/master/std/algorithm/sorting.d

Between "for(;;)", "while(true)" and "do while(true)", I would use the "while (true) { }" for pure readability and semantic reasons.

I reckon "for(;;)" form is used for debug reasons (so you can easily insert conditions to transform an infinite loop into a finite one).

On 25.11.2016 11:33, Claude wrote:
> ...
>
> Between "for(;;)", "while(true)" and "do while(true)", I would use the
> "while (true) { }" for pure readability and semantic reasons.
> ...

What semantic reasons?

> I reckon "for(;;)" form is used for debug reasons (so you can easily
> insert conditions to transform an infinite loop into a finite one).

You can just as easily edit the while condition. I use it because "unconditional loop" is less silly than "loop until true is false".

On Friday, November 25, 2016 12:10:44 Timon Gehr via Digitalmars-d wrote:
> On 25.11.2016 11:33, Claude wrote:
> > ...
> >
> > Between "for(;;)", "while(true)" and "do while(true)", I would use the
> > "while (true) { }" for pure readability and semantic reasons.
> > ...
>
> What semantic reasons?

Probably the complete lack of a condition to test in for(;;). I confess that I was shocked when I found out that it was legal to have a for loop without a condition. That seems like doing while() or if(), which makes no sense. So, I never use for(;;) and wish that it didn't exist, but it does, and some folks use it. So, I have to live with the possiblity of dealing with it when dealing with code written by other people. But I won't ever use it.

- Jonathan M Davis