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The reference D compiler is now open source

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Re: The reference D compiler is now open source

#91

Post by mamcx »

Ace17 wrote: post #50
JoshTriplett wrote: post #7

Earlier quoted context omitted.

> Each of dmd/gdc/ldc has their individual strengths and styles. I'd be really interested to hear a comparison of those from someone experienced with D and its community.

Professional D coder here. - DMD is by far the D compiler with the shortest compile time. It's actually so fast that it comes with a utility, 'rdmd', which compiles-then-execute a D program. Say goodbye to shell/perl/python scripts, now you can have compile-time checks without an explicit/slow compilation step. We use it for automation tasks. - GDC is the compiler of choice when it comes to supporting multiple target…

How good is D for:

-iOS? -Android? -Windows?

Re: The reference D compiler is now open source

#92

Post by floatboth »

Rusky wrote: post #82
amelius wrote: post #44

Earlier quoted context omitted.

Also, how does D compare to Rust? (If I'm going to learn a new system programming language, which one should I pick?)

D has been around longer, has powerful compile-time metaprogramming tools, and has a very fast compiler. However, it has a garbage collector, and is not entirely memory-safe by default (though is beginning to optionally incorporate some ideas from Rust [edit: or not], maybe making that easier once you put in the work). It seems to follow C or C++ in what sorts of things it makes language-level features. Rust is newer…

> a relatively slow compiler

Well… it's relatively slow in release mode, but C++ compilers can often be slower. GHC is always slower :D

Re: The reference D compiler is now open source

#93

Post by attractivechaos »

saosebastiao wrote: post #12

This was something that always rubbed me the wrong way about the language, and it was an impediment for adoption for me (for D, but also Shen and a few others). In this era, there is no excuse for a closed source reference compiler (I could care less if it's not a reference compiler, I just won't use it). I'm surprised it took this long to do this, it seems like D has lost most of its relevance by now...relevance it…

This is exactly my thought. I was really excited about D1 at the time when there were no Go/Rust/Swift/... I called D the C++ should be. I recommended D to almost everyone. They liked it. Some of them even wrote non-trivial programs in D. However, all of them went back to C/C++ later during the painful D1 to D2 transition amidst unnecessary clashes. It was a mess IMHO, which deeply hurt D's adoption. D2 managed to reach a consensus among different parties in the end, but at that point, Go was stabilized, Rust started to look promising with more exciting modern features. D is not the shiny and unique language any more. D had a chance to gain popularity, but now it has lost the momentum. It is a pity.

Re: The reference D compiler is now open source

#94

Post by gmfawcett »

dbcurtis wrote: post #86
jordigh wrote: post #45

Earlier quoted context omitted.

I guess the best comparison to Python would be the dunder methods. You know how in Python a class really is just a dict, right? Like, foo.bar is pretty much syntactic sugar for foo.__get_attribute__(foo.__dict__['bar']) in most cases. Or how a + b is sugar for a.__plus__(b). Well, imagine that all of the things you can do in Python by messing with dunder methods, function decorators, or metaclasses could be precomput…

Well, overriding dunder methods isn't really metaprogramming. It's just method inheritance/override. Is there anything in D similar to decorators? How does the registration pattern work in D, for instance?

Do you mean like this kind of registration decorator?

https://github.com/rejectedsoftware/vibe.d/blob/master/examp...

Decorators (in D, 'user defined attributes', or UDA) work differently. It's not a function-composition feature, but more of a tagging feature. You write a class, function, etc., tag it with custom attributes; and then have a separate compile-time function walk over your code, find the decorators, and augment the code based the meaning of the tags. (I used to wish that D had adopted Python-style decorators, since they are easy to reason about and implement, but I can see the logic of the more general UDA system that they adopted.)

In practice, though, you would often use templates to achieve the same effect. Given a memoize template (really, just a memoize function), and an expensive-computation function,

    auto fastComputer = memoize!expensiveComputer;
produces roughly the equivalent of

    @memoize
    def expensiveComputer(): ...
but with opportunities for compile-time optimization.

Re: The reference D compiler is now open source

#95

Post by stonemetal »

MichaelGG wrote: post #35
WalterBright wrote: post #20

Earlier quoted context omitted.

We investigated public domain, but that has international legal problems with it. Boost was the best solution.

Do you have any comment son international legal issues with public domain? Is that not recognized in some places?

The main problem with the public domain is that there is no such thing as "the public domain". Each country has its own copyright law, with its own terms and conditions. What the public domain means in the US is not what the public domain means elsewhere i.e. Germany. In Germany an author has Moral Rights which the author is incapable of giving up and may only transfer as apart of their will. So rather than require all German contributors to be dead and have a will that grants their moral rights to the project, using a permissive license gets the same effect.

Re: The reference D compiler is now open source

#96

Post by humanrebar »

jordigh wrote: post #48
jacques_chirac wrote: post #38

Earlier quoted context omitted.

There's plenty you can do with D but not C++, see regex, bitfields, swap member-by-member with checks for mutual pointers, the pegged library for grammars, etc etc.

I don't know, Boost has me convinced that even things like regexes in C++ templates could be possible, if your compiler has a big enough stack to handle very deep template recursions. It's theoretically possible to build a regex parser in C++ templates, right? It would be horrible, but possible.

> It's theoretically possible to build a regex parser in C++ templates, right?

You'd probably do large portions of it in "constexpr" types and functions rather than relying on recursive metaprogramming techniques.

They are also planning on adding overloading based on whether a function is constexpr, which is important if you want the same library to support both compile-time and run-time matchers.

So it's all theoretically possible already. But D has the advantage here in that it's not just possible but usable.

Re: The reference D compiler is now open source

#97

Post by bachmeier »

zerr wrote: post #51

Anybody worked on performance critical stuff in D? How good is its GC?

I think it's common to avoid the GC in performance critical sections of your code. D's version of BLAS is faster[1] and avoids the GC completely.

[1] http://blog.mir.dlang.io/glas/benchmark/openblas/2016/09/23/...

Re: The reference D compiler is now open source

#98

Post by bionsuba »

Rusky wrote: post #84
qznc wrote: post #72

Earlier quoted context omitted.

No problem, just add the @nogc annotation to your main function. int main(string[] args) @nogc { ... }

I haven't used D much- how much of an impact does that have when using the standard library or other libraries? Is there a good way to use things that assume a GC even when it's disabled?

There are many parts of the std lib that assume GC usage. When you mark a function as @nogc, DMD does a compile-time check and will not compile your program if there's a GC call. Applying this to main means that your entire program will by necessity be GC free.

Re: The reference D compiler is now open source

#99

Post by vram22 »

Ace17 wrote: post #50
JoshTriplett wrote: post #7

Earlier quoted context omitted.

> Each of dmd/gdc/ldc has their individual strengths and styles. I'd be really interested to hear a comparison of those from someone experienced with D and its community.

Professional D coder here. - DMD is by far the D compiler with the shortest compile time. It's actually so fast that it comes with a utility, 'rdmd', which compiles-then-execute a D program. Say goodbye to shell/perl/python scripts, now you can have compile-time checks without an explicit/slow compilation step. We use it for automation tasks. - GDC is the compiler of choice when it comes to supporting multiple target…

>- DMD is by far the D compiler with the shortest compile time. It's actually so fast that it comes with a utility, 'rdmd', which compiles-then-execute a D program. Say goodbye to shell/perl/python scripts, now you can have compile-time checks without an explicit/slow compilation step. We use it for automation tasks.

Right. See:

http://www.infognition.com/blog/2014/d_as_scripting_language...

Also of interest:

Why D?

http://www.infognition.com/blog/2014/why_d.html

Both pages down right now, maybe the site is down, but have read those pages earlier. Google cache or archive.org may also work. Infognition is a software product company (video and related products) that does a good amount of their work in D. No connection them, just saw the site while browsing for D info earlier.

Re: The reference D compiler is now open source

#100

Post by bionsuba »

zerr wrote: post #74
WalterBright wrote: post #67

Earlier quoted context omitted.

The performance of D is the same as that for the corresponding C/C++ program in the corresponding compiler. dmd and Digital Mars C++ gdc and gcc ldc and clang

I meant the situations when the GC is a bottleneck, and how people deal with it, by fine tuning GC, etc... Any war stories about this...

People on embedded systems use a custom runtime, and people who want to avoid the GC use the compiler to disallow GC usage in their entire program by using the @nogc annotation.

There are other less extreme solutions, such as the ability to have some threads be registered with the GC and others not. Also, you can just find your bottle-necks and mark those specific functions as @nogc. Some people also turn off automatic collections and manually trigger them only when it's ok to pause.

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