C++ Template Metaprogramming/

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Exploring More Examples of Range Adaptors

Exploring More Examples of Range Adaptors

Enhance your understanding of range adapters by analyzing some more examples.

We'll cover the following...

Previously in this section, we saw the following example (this time with explicit namespaces):

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namespace rv = std::ranges::views;
std::ranges::sort(v);
auto r = v
        | rv::filter([](int const n) {return n % 2 == 0; })
        | rv::drop(2)
        | rv::reverse
        | rv::transform([](int const n) {return n * n; });

This is actually the shorter and more readable version of the following:

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std::ranges::sort(v);auto r =
  rv::transform(
    rv::reverse(
      rv::drop(
        rv::filter(
          v,
          [](int const n) {return n % 2 == 0; }),
        2)),
    [](int const n) {return n * n; });

The first version is possible because the pipe operator (|) is overloaded to simplify the composition of views in a more human-readable form.

Passing arguments to range adaptors

Some range adaptors take one argument, and some may take multiple arguments. The following rules apply:

  • If a range adaptor A takes one argument, a view V, then ...