Not with the reverse pipe! I think <| was added at the suggestion of someone else. Maybe in the thread at ANN: Underscores.jl: Placeholder syntax for closures
Composition is normal composition. Like in your @f macro, but you don’t need a separate macro:
@f map(_^2) |> filter(exp(_) > 5)
# vs
@_ map(_^2, __) ∘ filter(exp(_) > 5, __)