ast-al / rangeless Goto Github PK

The exists_where operation takes a const Iterable& which makes it fail when used after fn::transform or other operators... I think that ones that generate seq? The issue seems to be that seq.begin is a non-const operation because seq is consumable.

I think that exists_where should work like for_each or foldl, both of which take Iterable&&. It's really just a foldl with a fixed algorithm that can return early.

First invocation works, second one doesn't:

std::vector<int> a = {1, 2, 3};
a % fn::exists_where([](auto item_a) { return item_a == 1; });
a % fn::transform([](auto item_a) { return item_a; }) % fn::exists_where([](auto item_a) { return item_a == 1; });

I get a compiler error when trying to use this library with a C++17 msvc2019 project:

"inserter" is not a member of "std"

Adding #include <iterator> fixes this.

I would send a pull request, but I am not experienced enough in C++ to have the confidence.

I have been playing around with rangeless as a faster compiling alternative to std::ranges and ranges-v3. I have been getting some compiler warnings that there are redundant or pessimizing moves in fn::transform and in fn::take_while. Would you consider removing the unnecessary std::move wrappers on lines 1592 and 1846? See this example. Thanks.