What a View! Building Your Own (Lazy) Range Adaptors (part 2 of 2) - Chris Di Bella - CppCon 2019

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What a View! Building Your Own (Lazy) Range Adaptors (part 2 of 2)

With their addition to C++20, ranges -- a revamped STL -- are going to send shockwaves through the way in which we design our software. The work from ranges gives us three broad things in C++20: redefined algorithms, concepts to assist in these algorithm definitions, and a handful of range adaptors, which are an abstraction over iterators for convenient program composition.

As Alex Stepanov and Sean Parent have said, the algorithms from the STL are only a sample of the algorithms that exist, and you're able to write your own. Range adaptors are no different: just because the adaptor you need isn't in C++20, doesn't mean that you can't write (or propose) it.

Using custom range adaptors can help you express your intentions in a much clearer manner. We'll spend some time implementing a range adaptor that isn't in the pipeline for C++20, starting from a motivating use-case, then move to how we implement the range adaptor -- including design considerations -- and finally, we'll write up a few tests to wrap everything up.
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Christopher Di Bella

Christopher Di Bella is a Staff Software Engineer for Codeplay’s ComputeCpp Runtime Technology. He is a strong proponent for generic programming in C++ and C++ education. Chris was previously a software developer for Nasdaq, and a tutor for UNSW Australia’s COMP6771 Advanced C++ Programming course in Sydney, Australia. When not geeking out over C++, he enjoys snowboarding, playing games, and watching films.
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[yuehuajia]

53:40 deduction guide make closesure constructor can accept lvalue ? and when supply lvalue i which type is int, closure template argument type is int&. Sound like this.

[YourCRTube]

range_adaptor_closure seems needlessly generic, considering it always takes one argument - the step?

[gieseanw]

Making your own range adapter seems pretty involved and full of gotchas.