Jacek

Generally YES, but with some minor change that would allow skipping defining function, so instead of:

$result = "Hello World"
    |> htmlentities(...)
    |> str_split(...)
    |> fn($x) => array_map(strtoupper(...), $x)
    |> fn($x) => array_filter($x, fn($v) => $v != 'O');

I'd rather see something like

$result = "Hello World"
    |> htmlentities(...) // or htmlentities(?)
    |> str_split(...)
    |> array_map(strtoupper(...), ?)
    |> array_filter(?, fn($v) => $v != 'O');

1. Separation of what (interface) and how (class/trait)
2. More balanced vote chart, now it's too green