@benh: It doesn't look like we're not using auto for return type deduction
yet. (Perhaps you're thinking about: auto f(...) -> return_type { ... })Return type deduction using auto is a C++14 feature. We explicitly don't support gcc-4.7 due to its lack of C++11 features, so I'll start at gcc-4.8. gcc-4.8 with -std=c++11 supports auto for return type deduction by default with warnings, but gcc-4.9 requires -std=c++1y or -std=c++14 to be specified. clang-3.3 requires -std=c++1y as well. I don't actually have clang-3.4 at the moment so I'm not sure, but clang-3.5 also requires -std=c++1y so I imagine clang-3.4 does the same. So in order to get auto for return type deduction I think we'd have to flip it up to -std=c++1y or -std=c++14. Thoughts? On 25 September 2014 05:36, Benjamin Hindman <b...@eecs.berkeley.edu> wrote: > +1 to growing the list of use cases for 'auto' organically. > > I agree with Cody that using 'auto' for return type deduction should also > be included, especially since we're already using it in libprocess. > > On Mon, Sep 22, 2014 at 10:50 AM, Cody Maloney <c...@mesosphere.io> wrote: > > > There are some cases where using auto for function return type deduction > is > > necessary to be able to state what you want generically in templates, > and I > > think we should allow that use case. I can ping some friends for good > > examples if people would like. Definitely general use of return type > > deduction shouldn't happen, but inside templates a lot of the time the > code > > is a lot simpler, more readable, and easier to maintain when using auto > > (Esp. c++14 return type deduction auto), than if a type has to be > > hand-deduced. > > > > Also note at times we just can't say what the type is, because it varies > in > > the template instantiation. See my use in > > https://reviews.apache.org/r/25525/diff/, slaveinfo_utils.cpp where > > writing explicit types for memberFunc is really hard if not impossible. > > > > On Mon, Sep 22, 2014 at 9:57 AM, Dominic Hamon <dha...@twopensource.com> > > wrote: > > > > > For reference: > > > http://google-styleguide.googlecode.com/svn/trunk/cppguide.html#auto > > > > > > We should be able to adopt that wholesale but please document anywhere > > you > > > think we would diverge from those examples. > > > > > > On Mon, Sep 22, 2014 at 7:28 AM, Alex Rukletsov <a...@mesosphere.io> > > > wrote: > > > > > > > We now start using auto in the code (among several other C++11 > > features). > > > > However we don't want to hamper reasoning about types. I would > suggest > > we > > > > select several use cases where we all agree using auto is welcomed > and > > > > several counterexamples. After the short conversation with BenH, we > > > agreed > > > > that iterators on one side and Try<>, Option<> on the other side are > > > first > > > > candidates for such list. I put the examples here > > > > <https://reviews.apache.org/r/25622/>. > > > > > > > > Any thoughts and ideas? > > > > > > > > > > > > > > > > -- > > > Dominic Hamon | @mrdo | Twitter > > > *There are no bad ideas; only good ideas that go horribly wrong.* > > > > > >
