Octal literals: who uses this?

[Don]

Walter Bright wrote:
> Don wrote:
>> and what the heck does "\000000\000000000\000\0000" mean?
> 
> It doesn't matter, because if you're translating C code to D, the code 
> is probably correct even if you don't know what it means.

Note that in C, you can't reasonably have \0 embedded in a string. But 
in both D and C# you can. So the "\0000" case isn't really a problem for 
C. It's far more likely in D that someone would write:
"1st\02nd\03rd\04th\0";
and expect it to work.

>> I doubt there is much extant C code which uses octal. Automated 
>> translations of octal literals can be done accurately, and you're even 
>> supplying the 'htod' converter!
> 
> htod is not intended for creating implementation source code. It's just 
> for headers. I expect most C translations will be done by hand.

The point is that a reasonable fraction of the few remaining instances 
of octal literals, will be machine translated, and will therefore be 
free from these errors.

> 
>> Note that C# doesn't have octal literals, but does include \0. So 
>> there's a precedent for dropping them. This also means that right now, 
>> converting code from C# to D can also introduce obscure bugs. I'd 
>> argue that that's a scenario that is at least as likely as bugs from C.
> 
> It is a good point, but I don't see people translating C# to D. But I do 
> see translating C to D (I do it myself!).
> 
>> I think the argument for octal is very, very weak.
> 
> The issue is really the cost of it being in vs the benefit of pulling it 
> out. I see very little cost of leaving it in, so it doesn't need much 
> benefit to make it worthwhile.

Inertia is the strongest argument, I think.
Octal-related bugs may occur
(1) when translating from ancient C code, if octal is removed.
(2) when translating from C#, if octal is retained.
(3) when writing new D code, if octal is retained.

IMHO, (2) and (3) are more probable than (1). However, all 3 cases are 
quite unlikely. It's extremely low on the list of priorities.