This is interesting and reminds me of a suggestion I made recently, i.e. if we define a let-operator:
let ( let& ) ch fn =
Fun.protect ~finally:(fun () -> close_in ch) begin fun () ->
fn ch
end
Then we can express this as:
let read_all filename =
let& ic = open_in_bin filename in
let len = in_channel_length ic in
really_input_string ic len
