Cinq (C++ inline query) is a header only, modern C++ library with no third-party dependency.

This library is inspired by Linq of C#. It will provide similar APIs and functionalities as Linq and PLinq along with extensions and adaptations to meet best-practices of modern C++.

This project plans to provide identical API and functionality in lastest successive two C++ standards (currently C++17 and C++14), and focuses on easy-to-use and performance.

The first relase will require C++17 to compile, and will only support a subset of the variations. (If we are lazy enough, C++14 might never get supported :P)

Warning:
Depend on the settings, building the test in non parallel mode requires up to 6GiB memory and 10GiB disk space.

Query implementation status:
Fully implemented:
Distinct()
Intersect(Enumerable<TSource>, ...)
Join(Enumerable<TOuter>, [](TInner) -> )
Select([](TSource) -> TResult)
SelectMany([](TSource) -> TEnumerable)
ToVector()
Where([](TSource) -> bool)

Need test case:
All([](TSource) -> bool)
ToSet()

To implement:
Aggregate([](TSource, TSource) -> TSource)
Aggregate(TAccumulate, [](TAccumulate, TSource) -> TAccumulate)
Aggregate(TAccumulate, [](TAccumulate, TSource) -> TAccumulate, [](TAccumulate) -> TResult)
Any() / Empty
Any([](TSource) -> bool)
Append(TSource)
Average([](TSource) -> TResult)
StaticCast<TResult>
DynamicCast<TResult>
ConstCast<TResult>
ReinterpretCast<TResult>
Contains(TSource)
Count() / Size / LongCount
Count([](TSource) -> bool) / CountIf
DefaultIfEmpty()
DefaultIfEmpty(TSource)
Distinct([](TSource, TSource) -> bool)
ElementAt(size_t) / At
ElementAtOrDefault(size_t)
Except(Enumerable<TSource>)
Except(Enumerable<TSource>, [](TSource, TSource) -> bool)
First() / Front
First([](TSource) -> bool)
FirstOrDefault()
FirstOrDefault([](TSource) -> bool)
GroupBy([](TSource) -> TKey)
GroupBy([](TSource) -> TKey, [](TKey, TKey) -> bool)
GroupBy([](TSource) -> TKey, [](TSource) -> TElement)
GroupBy([](TSource) -> TKey, [](TSource) -> TElement, [](TKey, TKey) -> bool)
GroupBy([](TSource) -> TKey, [](TKey, Enumerable) -> TResult)
GroupBy([](TSource) -> TKey, [](TKey, Enumerable) -> TResult, [](TKey, TKey) -> bool)
GroupBy([](TSource) -> TKey, [](TSource) -> TElement, [](TKey, Enumerable) -> TResult)
GroupBy([](TSource) -> TKey, [](TSource) -> TElement, [](TKey, Enumerable) -> TResult, [](TKey, TKey) -> bool)
GroupJoin(Enumerable<TInner>, [](TOuter) -> TKey, [](TInner) -> TKey, [](TOuter, Enumerable<TInner>) -> TResult)
GroupJoin(Enumerable<TInner>, [](TOuter) -> TKey, [](TInner) -> TKey, [](TOuter, Enumerable<TInner>) -> TResult, [](TKey, TKey) -> bool)
Intersect(Enumerable<TSource>, [](TSource, TSource) -> bool)
Intersect(Enumerable<TSource>)
Join(Enumerable<TInner>, [](TOuter) -> TKey, [](TInner) -> TKey, [](TOuter, TInner) -> TResult)
Join(Enumerable<TInner>, [](TOuter) -> TKey, [](TInner) -> TKey, [](TOuter, TInner) -> TResult, [](TKey, TKey) -> bool)
Last() / Back
Last([](TSource) -> bool)
LastOrDefault()
LastOrDefault([](TSource) -> bool)
Max()
Max([](TSource) -> TResult)
Min()
Min([](TSource) -> TResult)
OfType<TResult>()
OrderBy([](TSource) -> TKey)
OrderBy([](TSource) -> TKey, [](TKey, TKey) -> bool)
OrderByDescending([](TSource) -> TKey)
OrderByDescending([](TSource) -> TKey, [](TKey, TKey) -> bool)
Prepend(TSource)
Range(T, T)
Repeat(TResult, size_t)
Reverse()
Select([](TSource, size_t) -> TResult)
SelectMany([](TSource) -> TEnumerable, [](TSource, TElement) -> TResult)
SelectMany([](TSource, size_t) -> TEnumerable, [](TSource, TElement) -> TResult)
SelectMany([](TSource, size_t) -> TEnumerable)
SequenceEqual(Enumerable<TSource>)
SequenceEqual(Enumerable<TSource>, [](TSource, TSource) -> bool)
Single([](TSource) -> bool)
Single()
SingleOrDefault()
SingleOrDefault([](TSource) -> bool)
Skip(size_t)
SkipLast(size_t)
SkipWhile([](TSource) -> bool)
SkipWhile([](TSource, size_t) -> bool)
Sum()
Sum([](TSource) -> TResult)
Take(size_t)
TakeLast(size_t)
TakeWhile([](TSource) -> bool)
TakeWhile([](TSource, size_t) -> bool)
Union(Enumerable<TSource>)
Union(Enumerable<TSource>, [](TSource, TSource) -> bool)
Where([](TSource, size_t) -> bool)

ToList
ToForwardList
ToDequeue
ToStack
ToQueue
ToPriorityQueue
ToMap
ToUnorderedSap
ToSet
ToUnorderedSet


Pending:
ThenBy([](TSource) -> Tkey)
ThenBy([](TSource) -> Tkey, [](TKey, TKey) -> bool)
ThenByDescending([](TSource) -> Tkey)
ThenByDescending([](TSource) -> Tkey, [](TKey, TKey) -> bool)
ToArray
ToDictionary
ToHashSet
ToList
ToLookup