8 ms·
> It doesn't have async/await, That's just a C# idiom, and far from being the right or sane way to handle concurrency. Meanwhile C++ has active objects and fu
by geezerjay 8y ago
> It doesn't have async/await,
That's just a C# idiom, and far from being the right or sane way to handle concurrency.
Meanwhile C++ has active objects and futures and other concurrency design patterns.
> doesn't have a sane way to create simple web servers
Check POCO.
> doesn't have map/find/filter/etc on collections, at least not a version that won't span multiple lines or the whole screen because they require mandatory arguments (begin, end) that are useless 99% of the time because you want to operate on the whole collection anyway, etc.
That's a very silly complaint. You acknowledge that C++ does have map/find/filter (which at this stage is rather obvious to anyone who ever used C++) but somehow you're complaining that C++'s interfaces require programmers to specify where the collections should start and finnish.
- vardump 8y ago> but somehow you're complaining that C++'s interfaces require programmers to specify where the collections should start and finnish. I think it is a valid complaint. Most of time you want to apply something like "find" to the whole collection. I'd also love to have C++ standard maps (esp. unordered_map) where I only pay for what I use. Namely, due to C++ spec I have to pay for the nodes instead of having a flat, CPU cache efficient, buffer. In other words, a different map type where other items are allowed to move in memory when something is inserted or removed. Oh, while we're at it, it'd be nice if vectors etc. could realloc instead of allocating a completely new memory region and freeing the old one when more space is required. A more ergonomic allocator story for specifying alternative allocators would also be very nice for some niches, like when you need to avoid fragmentation or require better performance in embedded development.
- BurnGpuBurn 8y agoMemory allocation by STL has been broken for as long as I remember, which is at least twelve years or so. It's been a while but if I remember correctly it doubled its allocation every time it ran out or space.
- NullPrefix 8y agothis is implementation specific. Care to tell which compiler are you talking about?
- jcelerier 8y ago> It's been a while but if I remember correctly it doubled its allocation every time it ran out or space. why would you call this "broken" ? That's one of the most optimal solutions for reallocations if you append values continuously, since it will reallocate only logarithmically.
- gmadsen 8y agowhat? ha, that is the text book approach to reallocating an array for additional values to get log complexity
- vardump 8y agoI'm not so sure I'd want a 2GB vector to grow to 4GB, etc.
- jhasse 8y agoWhy not?
- dbaupp 8y agoO(n^2) time for n push_back calls would be worse, so some sort of multiplication/exponential growth is required for the "fits all" default vector and its default growth strategy.
- BeeOnRope 8y agoOld versions of MSVC used a 3/2 growth factor which led to less extreme jumps for large vectors, although also a lot more copies when filling a small vector. I'm not sure if that's still true.
- ChrisSD 8y ago
- jcelerier 8y ago> I think it is a valid complaint. Most of time you want to apply something like "find" to the whole collection. frankly, this is a very overstated problem. It's trivial to write a header with such functions (e.g. https://github.com/OSSIA/libossia/blob/master/OSSIA/ossia/detail/algorithms.hpp https://github.com/OSSIA/libossia/blob/master/OSSIA/ossia/de...). And it's already provided by Boost if you use it.
- vardump 8y agoYeah, it's trivial to do that. But since it's not in STL, everyone will use a bit different implementations for something this mundane and common.
- michal_f 8y agoAs to mem allocation in vector: https://github.com/facebook/folly/blob/master/folly/docs/FBVector.md https://github.com/facebook/folly/blob/master/folly/docs/FBV...
- mschuetz 8y ago> That's just a C# idiom Not just C#, Python and JS also have it already. And async-await is the first time ever where I've thought that yes, this is a good way to do single-threaded async (event-queue-ish) or even multi-threaded things. > Check POCO. Thanks for the hint, I will check it out. > but somehow you're complaining that C++'s interfaces require programmers to specify where the collections should start and finnish. Take a look at: http://www.modernescpp.com/index.php/higher-order-functions http://www.modernescpp.com/index.php/higher-order-functions The c++ functions are unnecesarely verbose compared to other languages. This transform(vec.begin(), vec.end(), vec.begin(),[](int i){ return i*i; }); could be much more readable as vec.map([](int i){ return i*i; }); Also makes for-of the better choice in my opinion because if you're going to write more code, I'd rather write code that is readable.
- aaaaaaaaaab 8y agohttps://en.cppreference.com/w/cpp/experimental/ranges https://en.cppreference.com/w/cpp/experimental/ranges
- __s 8y agoRust is also getting async/await
- steveklabnik 8y agoWhich de-sugars to generators, which is similar to, but different from, the various C++ coroutine proposals. I haven’t dug into this one yet though... It’s going to be pretty important for us: http://aturon.github.io/2018/04/24/async-borrowing/ http://aturon.github.io/2018/04/24/async-borrowing/
- hhmc 8y agoThose examples aren't really the same though. Transform is a free function which operates on anything that satisfies 'ForwardIterator', map would be a member function of the vector class. Theoretically you could add helper functions to all suitable containers which calls through to transform (I think this is what you're suggesting). But it would feel very heavyweight and add a lot of cruft to the std library. You could also add your own utlity free function similar to template<class T, class F> void mymap(T &t, const F &f){ std::transform(t.begin(), t.end(), t.begin(), f); }