lukaskollmer · February 3, 2019 12:26
diff --git a/count_homebrew_cleanup.ml b/count_homebrew_cleanup.ml
 (*
 OCaml program to count the total amount of space freed up when running `brew cleanup`

 Usage:
    brew cleanup | ocaml count_homebrew_cleanup.ml

 Author: Lukas Kollmer <lukas.kollmer@gmail.com>
 Date: 2019-02-03
 License: MIT
 *)

 let read_stdin () =
  let rec imp acc =
    try imp (input_line stdin :: acc)
    with End_of_file -> List.rev acc
  in
  imp []



 type comparison_result = Same | Less | Greater

 let compare_len a b =
  match String.length a, String.length b with
  | x, y when x > y -> Greater
  | x, y when x = y -> Same
  | _ -> Less


 let string_has_prefix pre str =
  match compare_len pre str with
  | Greater -> false
  | Same -> str = pre
  | Less -> String.sub str 0 (String.length pre) = pre

 let string_has_suffix suf str =
  match compare_len suf str with
  | Greater -> false
  | Same -> str = suf
  | Less ->
    let suf_len = String.length suf in
    String.sub str (String.length str - suf_len) suf_len = suf


 let rec get_last = function
  | [] -> failwith "get_last" 
  | x::[] -> x
  | x::xs -> get_last xs


 let split_last char str =
  String.split_on_char char str |> get_last

 let split_first char str =
  String.split_on_char char str |> List.hd


 let parse_byte_string str =
  let count = str |> split_first 'B' |> split_first 'K' |> split_first 'M' |> split_first 'G' |> float_of_string in
  if string_has_suffix "MB" str then
    count *. 1e+6
  else if string_has_suffix "KB" str then
    count *. 1e+3
  else if string_has_suffix "GB" str then
    count *. 1e+9
  else (* bytes, probably *)
    count


 (* basic idea inspired by https://stackoverflow.com/a/1094933/2513803 *)
 let format_byte_count count =
  let rec imp count = function
    | [] -> Printf.sprintf "%.2f GB" count
    | x::xs -> if Float.abs count < 1024. then Printf.sprintf "%3.1f %s" count x else imp (count /. 1024.) xs
  in
  imp count [""; "KB"; "MB"]
  

 let () =
  read_stdin ()
  |> List.filter (string_has_prefix "Removing: ")
  |> List.map (fun line -> line |> split_last '(' |> split_last ' ' |> String.split_on_char ')' |> List.hd)
  |> List.map parse_byte_string
  |> List.fold_left (+.) 0.
  |> format_byte_count
  |> Printf.sprintf "Total: %s" |> print_endline
	(*
	OCaml program to count the total amount of space freed up when running `brew cleanup`

	Usage:
	brew cleanup \| ocaml count_homebrew_cleanup.ml

	Author: Lukas Kollmer <lukas.kollmer@gmail.com>
	Date: 2019-02-03
	License: MIT
	*)

	let read_stdin () =
	let rec imp acc =
	try imp (input_line stdin :: acc)
	with End_of_file -> List.rev acc
	in
	imp []



	type comparison_result = Same \| Less \| Greater

	let compare_len a b =
	match String.length a, String.length b with
	\| x, y when x > y -> Greater
	\| x, y when x = y -> Same
	\| _ -> Less


	let string_has_prefix pre str =
	match compare_len pre str with
	\| Greater -> false
	\| Same -> str = pre
	\| Less -> String.sub str 0 (String.length pre) = pre

	let string_has_suffix suf str =
	match compare_len suf str with
	\| Greater -> false
	\| Same -> str = suf
	\| Less ->
	let suf_len = String.length suf in
	String.sub str (String.length str - suf_len) suf_len = suf


	let rec get_last = function
	\| [] -> failwith "get_last"
	\| x::[] -> x
	\| x::xs -> get_last xs


	let split_last char str =
	String.split_on_char char str \|> get_last

	let split_first char str =
	String.split_on_char char str \|> List.hd


	let parse_byte_string str =
	let count = str \|> split_first 'B' \|> split_first 'K' \|> split_first 'M' \|> split_first 'G' \|> float_of_string in
	if string_has_suffix "MB" str then
	count *. 1e+6
	else if string_has_suffix "KB" str then
	count *. 1e+3
	else if string_has_suffix "GB" str then
	count *. 1e+9
	else (* bytes, probably *)
	count


	(* basic idea inspired by https://stackoverflow.com/a/1094933/2513803 *)
	let format_byte_count count =
	let rec imp count = function
	\| [] -> Printf.sprintf "%.2f GB" count
	\| x::xs -> if Float.abs count < 1024. then Printf.sprintf "%3.1f %s" count x else imp (count /. 1024.) xs
	in
	imp count [""; "KB"; "MB"]


	let () =
	read_stdin ()
	\|> List.filter (string_has_prefix "Removing: ")
	\|> List.map (fun line -> line \|> split_last '(' \|> split_last ' ' \|> String.split_on_char ')' \|> List.hd)
	\|> List.map parse_byte_string
	\|> List.fold_left (+.) 0.
	\|> format_byte_count
	\|> Printf.sprintf "Total: %s" \|> print_endline