On Tuesday, 14 July 2015 at 09:44:08 UTC, Ola Fosheim Grøstad
wrote:
On Tuesday, 14 July 2015 at 08:54:42 UTC, Laeeth Isharc wrote:
Now one may say that this isn't all he was saying, that the GC
in D can be improved, that D could be safer, and so on. But
it's hardly fair to suggest the original poster is not right
about one of the advantages of D vs C and C++.
The linked webpage explicitly states that C UB for integer
overflow gives 2x performance in some scenarios. Something
these forums have tried to play down many times.
Perhaps - I haven't measured these things myself, and don't
recall downplaying of this in the short term I have been here,
but I have no reason to think that's wrong.
But my point was one of good form. You seemed to slam the
original poster, who who made no stronger or more concrete
assertion than that safety is a benefit of D [we surely know by
now that linking to a piece implies endorsement of it only as
being interesting, not more]. Perhaps that's a point
well-founded in reality, but I didn't see you argue for it.
I have no interest in pursuing controversy further, but it really
is a mystery to me as to why you don't do something constructive
towards shaping the world as you would like to see it. Code wins
debates, and a DIP is less work than implementing the whole thing
oneself. It is of course possible there is background to which I
am not privy, and that that is why it is mysterious.
You have compiler-options/libraries/tools for C++ that allows
you to write as safe and safer code than D (which lacks
sanitizers) at the cost of performance and convenience. Just
like D defaults sacrifice performance for the same, but D tries
to give priority to convenience. Which C++ does not have much
of (convenience that is). C++ has an impressive range of
options that beats all alternatives in the
flexibility-department, but also high complexity levels and
tedious syntax.
I'll certainly take programmer productivity if I don't need to
pay too much for it, and if the aesthetic experience of getting
my stuff done can be made something pleasurable. I am not sure
however if you are making an argument to justify your implicit
position, since it seems we both have similar assessments of C++
as its used, or easy to use. I do not think it is controversial
either to observe that C++ has more options!
Life in the commercial world involves pragmatic choices. So the
missing piece in your argument would be to demonstrate that
programmer productivity ('convenience') and non-tedious syntax
are not all that important. Conventional wisdom seems to be that
productivity matters more than efficiency (personally I don't
mind trading off a little, but there are limits!)
It is just that if you use C++ over Java you do it because you
need performance and deliberately through-and-through avoid
those features/library/compiler options/tools and resort
writing code that is less robust.
I don't know - I think there are many factors that go into such a
decision. It's a big world, and I wouldn't pretend to know what
shapes problems in different domains. What is discussed in the
media is not necessarily representative of what actually goes on
amongst people quietly getting their work done. I am told that
Java is often faster than C++ and needn't be a memory hog - maybe
that is right, but in practice stuff written in C,C++,D in a
sensible, mature, thoughtful fashion but without too much special
effort given to optimisation seems to just run fast without a
need for tuning or any dark magic. I am probably not tuning it
right, but even in 2015 one doesn't seem to be impressed by the
performance and memory efficiency of Java apps.
My C++ libraries do void casts and lots of other low level
stuff, not because C++-eco system does not provide robust
alternatives, but in order to work with raw memory. I would
never dream of doing that in a language like Go or Java. I do
it because I _need_ the performance that C/C++ brings and also
need to tailor low level constructs/hardware/OS. Which I could
not do at all in Go/Java.
If you do the same in D, you are in the same boat as C++,
except C++ is more tedious and C++ provide sanitizers.
Do you need to in the whole part of what you are writing, and if
you do, are you in the same boat?
But there are restricted and annotated versions of C that
offers provable safety at the cost of development time, but
with C performance. Thus is much better than D for _secure_
performant system level programming since you also have both
termination and run-time guarantees.
But commercial life is about trade-offs and pragmatic choices,
and the Pareto principle applies here too. Ie I should think the
subset of reasonably secure, reasonably efficient systems level
programming is rather larger than the narrow domain you speak of
above.
Of course, nobody use D for critical system level programming,
so that is not really an issue in the forseeable future.
I don't know what "systems programming" means any more, only what
it meant 30 years ago. Wouldn't you say that Weka, Sociomantic,
possibly the guys doing the Norwegian subway announcement system
have at least aspects of system level programming and can be
described as critical? The hedge fund about which Andy Smith
spoke - their application may or may not be systems level, but it
strikes me as not so far from that.
Good enough rebuttal? Slamdunk C/C++ for the right reasons:
complexity and tedium. Complexity and tedium make people more
likely to make fatal mistakes... but that's ergonomics, not
semantics.
A rebuttal would have been to demonstrate that the OP was making
a silly point that cannot be justified. You have yourself
suggested that if you want to use C and C++ in a safe way then it
comes at quite a price. Commercial adoption is after all driven
by these sorts of things.
