Unlike pipe operators in functional languages, the Hack proposal is aimed at composition of
expressions instead of
functions. This makes the proposal extremely pervasive and unfocused, enabling people to write `a |> %[0]` instead of `a[0]`, for instance.
Proponents argue it’s great because you can pipe arbitrary expressions without nesting or needing temporary variables, but opponents argue it harms readability and will result in needless style arguments.