"Anders F Björklund" <afb@algonet.se> wrote in message news:d1c3n4$1164$1@digitaldaemon.com...
> Lionello Lunesu wrote:
>
>> So that's the reason D's front-end (../dmd/src) is in C++: because it's using the C compiler's back end and that one's in C/C++?
>
> If DMD was written in D, what would you use to bootstrap it with ?
>
> And you would have all the woes of the current compiler, like not being able to create shared libraries, missing debug info, plain old bugs, and other things that make D yet unreleased...
>
> No, I for one think it's a good thing that DMD front-end is in C++.
>
How about writing a small compiler in something like c that only covers a small part of the D and use that compiler to create the full version.

I know of a modula-2 compiler that is built this way.

Zz

Ilya Minkov wrote:

>> Especially when it would be more useful to update it to, for instance, work with GCC 4.0; instead of just doing a work-a-like but written in D?
> 
> Why should this be a problem? GCC backend, being written in C, can be
> talked to from any language one can compile, when a compatible C
> compiler exists. In fact, GNU Pascal frontend is written in Pascal, etc.

It's not really a problem, like you say, just thought it be more work?

Had the interface been in C++ instead, matters would be different...
But interfacing with regular C, that D can do without too much hassle.

> I think i recall Walter saying he wants to have D frontend written in D
> someday. However, it's definately not time yet now so i think we can
> pick up on this discussion when we are past the currently awaited
> milestones.

Agreed. I'm not trying to stop it at all, as long as GDC still works :-)

--anders

Nick Sabalausky wrote:
> "Anders F Björklund" <afb@algonet.se> wrote in message news:d1c3n4$1164$1@digitaldaemon.com...
> 
>>Lionello Lunesu wrote:
>>
>...
> 
> The first 'DMD written in D' would be compiled with the latest C/C++-written version. Subsequent versions would be compiled with the previous build.
> 
> Unless I misunderstand what you mean by 'bootstrap'...?
> 
> 
>>And you would have all the woes of the current compiler, like
>>not being able to create shared libraries, missing debug info,
>>plain old bugs, and other things that make D yet unreleased...
>>
>>No, I for one think it's a good thing that DMD front-end is in C++.
>>
>>--anders 
> 
> 
> 
That's essentially the approach that Algol took to distribution back in the 1960's.  It worked, too.  (Algol had a minimal subset compiler written in assembler.  The minimal subset was used to write a compiler for the full language.  The full language was used to create the libraries...)

Algol was the first time I heard about the bootstrap process.  It was quite successful yielding such descendants as Pascal and Ada, and, less completely, any language that uses block structured code.

"Martin M. Pedersen" <martin@moeller-pedersen.dk> wrote in message news:d1cpb7$1pg9$1@digitaldaemon.com...
> It has been a natural place to start, but a move to D would IMHO be a natural evolotion, and a good proof of concept. Walter may have his
reasons
> to keep the implementation in C++ for now. I can only guess on what they could be, but guesses would include:
>
>     - other issues are deemed to have higher priority.

Yup.

>     - the interface to his backend isn't trivial.

Right. There are a number of .h files, the back end is in C++, and it would be a fair chunk of work to interface it. I've got far too many other things to do right now.

In article <d1c9o0$1670$2@digitaldaemon.com>, =?ISO-8859-1?Q?Anders_F_Bj=F6rklund?= says...
>
>Stewart Gordon wrote:
>
>> The obvious way to bootstrap D on a new platform would be to keep hold of the C++-written DMD until a better solution is found.  FTM, what does a new platform's first C compiler tend to be written in?
>
>Usually bootstrapped using assembler. Or cross-compiled, if available.

I would say that a C cross compiler would be the first choice for a new CPU with a smattering of assembler.