/// --------
///
/// template<class Projection, class F>
-/// constexpr proj_adaptor<Projection, F> by(Projection p, F f);
+/// constexpr proj_adaptor<Projection, F> proj(Projection p, F f);
///
/// template<class Projection>
-/// constexpr proj_adaptor<Projection> by(Projection p);
+/// constexpr proj_adaptor<Projection> proj(Projection p);
///
/// Semantics
/// ---------
///
-/// assert(by(p, f)(xs...) == f(p(xs)...));
-/// assert(by(p)(xs...) == p(xs)...);
+/// assert(proj(p, f)(xs...) == f(p(xs)...));
+/// assert(proj(p)(xs...) == p(xs)...);
///
/// Requirements
/// ------------