Supercomputing Centre, Research Centre Julich, Germany (0) How to chunk a sequence? > Different range adaptors dividing a range into subranges available: std: :Views: :chunk(chunk_size) std: :Views: :chunk_by(Predicate) ,0x4,0x5 ,0Ox6 ,0Ox7 ,0Xx8 ,0x9,OxA,OxB ,0OxC ]; fmt::println('"{:::X"，range | std::views::chunk(5)); fmt::println("{:::XJ"，range | jsc::chunk_evenly(5)) 了 七 加 [[0,，1，2，3,，4]，[5，6，7，8，9] ，[A，B，O]] 忆 气 func(chunk) ; change range adaptor 二 了 (6) Number of instructions & branches 力 std: :vievs::chunkO) 30 大 jsc::chunk_evenly(O)

std::same_as; }; template concept GravitationalRange = GravitationalBodyrange_value_t>; 1 2 3 4 5 6 7 8 9 10 78910def GetForceOnBody(this_body, all_bodies): all_forces ranges::views; } 1 2 3 18Range View Semantically: a collection of "things". Has begin and end functions. That's it. A speci�c type of range. Can be used in range adaptor pipelines. O(1) move (and is true. template concept range = requires(T& t) { ranges::begin(t); ranges::end(t); }; template concept view = ranges::range && movable &&

(C++98) algorithm(begin(range), end(range)) ➡ result 8C++ RANGES LIBRARY Extension and generalization of the algorithm and iterator libraries. (C++98) algorithm(begin(range), end(range)) ➡ result (C++20) (C++20) algorithm(range) ➡ result (C++20) adaptor(range) ➡ view (C++20) range | adaptor ➡ view (C++20) range | adaptor1 | adaptor2 ➡ view 8.1C++ RANGES LIBRARY Extension and generalization of the algorithm algorithm(begin(range), end(range)) ➡ result (C++20) algorithm(range) ➡ result (C++20) adaptor(range) ➡ view (C++20) range | adaptor ➡ view (C++20) range | adaptor1 | adaptor2 ➡ view (C++23) range | adaptor1

Express your expectations CppCon 2023-10-03 10JSON parsing in C++ auto parse_json(std::ranges::input_range auto json) -> ???; Jonathan Müller — @foonathan Express your expectations CppCon 2023-10-03 11JSON 2023-10-03 12JSON DOM parser Idea: Represent a JSON value in C++. auto parse_json(std::ranges::input_range auto json) -> std::expected; Jonathan Müller — @foonathan Express your expectations @foonathan Express your expectations CppCon 2023-10-03 18Full usage auto parse_json(std::ranges::input_range auto json) -> std::expected { // provided by JSON library } auto parse_co

notified that the work is complete35 OPERATIONS EXECUTE OUTSIDE-IN when_all then schedule Every adaptor has a chance to run code when the operation is starting and when the operation is finishing awaiting coroutines is unwound.) • The cancellation “exception” is “caught” by applying a sender adaptor that translates the done signal into a value or an error before awaiting the sender; e.g., with: key click as a sender 2. Model keyboard input as a range of senders 3. Model interrupt (e.g., Ctrl-C) as a sender 4. Asynchronously transform range of senders into clicky noises until interrupt sender

7talk outline talk outline range basics & concepts range algo details and survey range views details and survey adjuncts observations & futures 2 . 8Range Basics Range Basics 3 . 1ranges, algorithms algorithms, views, adaptors range: something that can be iterated over range algo: algorithm that takes range view: lazy range thats cheap (to copy) range adaptor: make a range into a view 3 . 2mechanics ranges::views {...}; //range adaptors namespace views = ranges::views; //shortcut to adaptors } namespace rng = std::ranges; //some examples in this talk 3 . 3what's a range? what's a range? iterator pair

Global and Local - “Global Iteration” supported over distributed range of elements - “Local iteration” supported over local range of elements #include int main(int argc, char **argv) Global and Local - “Global Iteration” supported over distributed range of elements - “Local iteration” supported over local range of elements in process’ memory #include int main(int Latency bound! Can we do better?HashMapBuffer - Constructed from a HashMap - Similar to a range adaptor, but relaxes when operations take place - Aggregates fine-grained insertions into large

Modifying algorithms • Removing algorithms • Mutating algorithms • Sorting algorithms • Sorted range algorithms • Numeric algorithms 24CppCon 2021 – Back to Basics: Classic STL Copyright © 2021 Bob Ranges • In the STL, iteration over sequences is based on the idea of iterator ranges • An iterator range is represented by a pair of iterators -- [first, last) • This pair represents a half-open interval dictionary 63CppCon 2021 – Back to Basics: Classic STL Copyright © 2021 Bob Steagall Container Adaptor: Stack template> class stack; • Features • Wrapper type that

18: return std::unexpected(parse_error::invalid_char); 19: } catch (const std::out_of_range &error) { 20: return std::unexpected(parse_error::overflow); 21: } catch (...) { 22: maybe-like types — std::optional, shared_ptr, raw ptrs, result of find (?) • maybe_view — Part range (can iterate over, etc.) — Part optional (at most 1 value) • Give us the basis to implement anything maybe-like types — std::optional, shared_ptr, raw ptrs, result of find (?) • maybe_view — Part range (can iterate over, etc.) — Part optional (at most 1 value) • Give us the basis to implement anything

A =std::allocator> class C> struct Adaptor { C my_data; void push_back(T const& t) { my_data.push_back(t); } }; Adaptor a1; Adaptor a2; a1.push_back(0); class C = vector> struct Adaptor {...}; vector vec; //- std::vector> Array arr; //- Array Adaptor adp; //- Adaptor

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