string to char array?

[Kyoji Klyden via Digitalmars-d-learn]

On Thursday, 4 June 2015 at 22:28:50 UTC, anonymous wrote:
>
> Generally, a `char**` is a pointer to a pointer to a char. 
> There may be more pointers to chars behind the pointed-to one. 
> And there may be more chars behind the pointed-to ones. You 
> can't know just from the type. You have to read the 
> documentation of the involved functions for the specifics.
>

Alright, kinda a bummer I need to do some digging for each 
third-party function I use, but oh well.
This probably comes from lack of experience but I can't really 
imagine ever writing something that is more than one or two 
pointers long.. like wouldn't that call for a redesign of 
whatever library was being written?



On Thursday, 4 June 2015 at 22:33:13 UTC, Ali Çehreli wrote:
>
> Yep, "C's biggest mistake":
>
>
> http://www.drdobbs.com/architecture-and-design/cs-biggest-mistake/228701625
>
> Ali

Thx for the link. I think I read this a couple years ago, but at 
the time had no idea what Walter was talking about. (probably 
because I was only using Python back when I read it)


>> Also does D primarily use explicit length field strings?
>
> I'm not sure if I understand you right, but yes, D arrays carry 
> their length. And D `string`s are arrays. You should encounter 
> things like `char**` pretty much only when talking to C code.
>
> By the way, there are subtly different meanings of "array" and 
> "string" which I hope you're aware of, but just to be sure:
> "array" can refer to D array types, i.e. a pointer-length pair, 
> e.g. char[]. Or it can refer to the general concept of a 
> contiguous sequence of elements in memory.
> And as a special case, "string" can refer to D's `string` type, 
> which is an alias for `immutable(char)[]`. Or it can refer to a 
> contiguous sequence of characters in memory.
> And when ketmar writes: "it's a pointer to array of pointers to 
> first chars of strings", then "array" and "string" are meant in 
> the generic way, not in the D-specific way.

Yeah that's what I meant. I just got the phrasing for that out of 
a compiler book I have.
I now see alot of my confusion is coming from me poorly assuming 
C, D, and sometimes C++ are functioning/handling data the same 
way. Clearly there's more to it than simply 
ProgrammingLanguage->IR->MachineCode (obviously to horribly 
simplify it).

So how does D store arrays in memory then?

I know you already explained this part, but..
Does the slice's pointer point to the slice's position in memory? 
Then if an array isn't sequential, is it atleast a sequence of 
pointers to the slice structs (& those are just in whatever spot 
in memory they could get?)
There's a slice for each array index..right? Or is it only for 
the first element?

Thanks!