Re: [boost] C++ Manifesto

Subject: Re: [boost] C++ Manifesto
From: Raindog (raindog_at_[hidden])
Date: 2009-09-10 16:16:38

Christian Schladetsch wrote:
> I wrote: A problem seems to be that we are trying to be meta-meta when meta-
> alone suffices.
>
> > The GCC frontend hasn't been integrated into mainline GCC, the LLVM
> > frontend is beta and similarly lives out of tree. A substantial,
> > incompatible, rewrite of the language is currently in progress.
> >
>
> The same can be said for C++0x.  And LLVM is not in beta w.r.t Apple.
>
>
> >
> > I've used D for some fun side projects, it is a nicer language than C++.
> > However, would I suggest using it at work, and risking a major, long-living
> > software project on it? Unfortunatly not yet, and most people I've
> > personally spoken to agree.
> >
>
> I am speaking out of my backside when I say anything on this matter, as I
> have not written anything substantial in D.
>
> But my original point remains: why not? There are no tablets written in
> stone stating Thou Shalt Write In C++. Sure, there are many people that are
> "language lawyers" and understand the finer intricacies of ADL and that is
> their livelihood. Great for them.
>   
I've considered writing some things in D but it lacked some extremely 
low level features that I needed for my project. For me it would meet my 
requirements for utility apps, but not my main project.

> Most of us understand (or could understand) most of boost. It isn't that
> hard - most of the "chicanery" is to do with xplat systems creating
> code-paths that even the original authors don't understand.
>
> The rest of the magic is in Spirit and similar expression-template-based
> systems that are only hard to understand because of their working domain. If
> they were written procedurally, they would be fine, or if they were written
> in ML they would be fine but because they are written in a strange mixture
> of bastardised C++ they are esoteric and deemed to be "excellent C++".
>
> I'm sorry. I don't think that Spirit is excellent C++. I think it is
> terribly clever C++ and I think that it represents a disservice to the C++
> community. Further, I think it has singularly set back language development
> by years. The damage is untold - if only there was active C++ support for a
> system like ANTLR for the past few years rather than Spirit then maybe we
> wouldn't be in the mess we are in now.
>   

I don't have anything to say about ANTLR, but being able to write a 
grammar no matter how simple or complex easily in C++ without having to 
rely on external tools was very appealing to me. I've used spirit to 
write 4 very simple parsers and the performance of them was very high. I 
could have used regular expressions or written a custom parser, but 
spirit was much easier than writing a custom parser and much faster than 
regex
> To be clear, I don't mean any disrespect to Joel or to the Spirit2 code-base
> per se. I just don't think that the C++ compiler was ever meant to be a
> language tool. I personally have witnessed at least two groups of coders
> reject a DSL-based solution because they thought that to do so "correctly"
> would mean using Boost.Spirit, which was beyond them. Meanwhile, ANTLR has
> no C++ support. It's a crying shame. Why is there no Boost.ANTLR?
>
> The question then stands: why stick with C++ for everything? What can D do
> in similar circumstances? (I know the immediate answer is "we don't use D"
> but can we please put that aside for a year).
>
> I don't know. I haven't used it. I have nothing to do with Digital Mars or
> Alex. I care only about writing effective code.
>
> I feel that C++?? is becoming just that. It doesn't matter that I can
> (eventually) understand the latest boost library, or the latest boost
> technique. What matters is what is the best way to write efficient code?
>
> Because I can agree with you, when you think that you are writing a lot of
> boilerplate nonsense to get basic things done.
>
> Move semantics and the problems that Ion is having is a case in point. I
> don't mean to be a misery-guts, but after having looking deeply at the
> issues I really don't see a way that it can be done without a language
> change. C++ is a fine language, but seriously, the authors didn't have any
> idea on how we'd use it and the differences are compounding exponentially.
>
> When C++ is no longer the best way (and yes, that is a "when" not an "if"),
> I would like to think that I am open-minded enough to be on that wave. Is
> that time sooner rather than later?
>
> Say you want to write a parser/AST walker/executor for a basic language with
> scoped variables and continuations. Is Boost.Spirit the best way to do so?
> Is it *really*?
>
> Say you want to write an object factory with persistent objects. Is
> Boost.Serialisation and Boost.Function the best way forward? How will you
> you store the functions?
>
> Say you want automatic resource management. shared_ptr<> doesn't cut it. It
> is too slow for single-threaded and at the same time doesn't deal with
> cycles.
>
> Say you want to write a geometry library. Ok, stop right there....
>
> Is Boost.Graph the best way to make a basic DAG?
>
> I've tried all these systems. They work, there is no doubt. Do they work
> well, in practice?
>
> Has there been any real-world review of the efficacy of boost libraries in
> general? I'm sure there has, as many here could attest, but this is a biased
> sample set. I wonder how much and what aspects of boost are used in the
> wider community?
>
> I for one use foreach, shared_ptr, unordered, mpl, some fusion, and other
> bits and pieces. No-one in my team uses anything other than foreach and
> shared_ptr - and there is a lot of confusion I have to deal with relating to
> their use of weak_ptr<> and locking etc with that. It seems that 5 years ago
> I had to argue that boost was Ok to use, and I still feel like I am saying
> the same things. I am approaching the stage where I wonder why I continue to
> apologise for it.
>
> What do you use?  Which parts of boost are good to use with least impact?
>   
I use spirit, xpressive, algorithm, foreach, shared_ptr, bind, phoenix, 
filesystem and program_options. I really like filesystem and spirit.

> This has turned into a manifesto against boost. I didn't mean that to be the
> case when I started, but so be it. I come from the real world, and there are
> real programmers that just don't know and don't want to deal with problems
> they can't solve. As a lead, I have to make technology decisions and I am
> clearly frustrated with the potential of both boost and C++ in general.
> Sometimes I think that it would be easier to just change language completely
> to C#/asm or D/C++/asm.
>   
Most games are already developed with some type of scripting front end. 
Unreal engine based games have unrealscript, wow and warhammer have lua, 
eve and pirates and age of conan have python, aoc even uses boost.python 
and darkfall uses java.
> I am in the position now to decide what will be the language for the next
> game made in company A. I am strongly tempted to make the core in C# with
> callouts to C++ libs for physics and render. Personally, after 20-odd years
> and still seeing the likes of Lucanus swing on the rope with his geometry
> lib, it makes me wonder if C++ is really what the real-time world needs.
>   

When it comes down to it, I can't really see anything that most other 
languages have to offer that make them better than C++ other than 
libraries. C# has .NET and Java has the JDK, python and ruby both have 
big standard libraries and C++ literally only has a handful of 
algorithms and containers. That in my opinion is the #1 shortcoming of C++.
> Regards,
> Christian.
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