RosettaCodeData/Task/Inverted-index/OCaml/inverted-index.ml
2024-10-16 18:07:41 -07:00

81 lines
2.2 KiB
OCaml

TYPE_CONV_PATH "Inverted_index"
type files = string array with sexp
type inverted_index = (string * int list) list with sexp
type t = files * inverted_index with sexp
open Sexplib
let data_file = "data.inv"
let data_path = Filename.concat Filename.temp_dir_name data_file
let get_inv_index() =
if Sys.file_exists data_path
then t_of_sexp(Sexp.load_sexp data_path)
else ([| |], [])
let load_file f =
let ic = open_in f in
let n = in_channel_length ic in
let s = String.create n in
really_input ic s 0 n;
close_in ic;
(s)
let array_push ar v =
let len = Array.length ar in
Array.init (succ len) (fun i ->
if i < len then Array.unsafe_get ar i else v), len
let uniq lst =
let h = Hashtbl.create (List.length lst) in
List.iter (fun x -> Hashtbl.replace h x ()) lst;
Hashtbl.fold (fun x () xs -> x :: xs) h []
let combine words i inv_index =
let h = Hashtbl.create (List.length inv_index) in
List.iter (fun (w, from) -> Hashtbl.replace h w from) inv_index;
List.iter (fun w ->
let from =
try Hashtbl.find h w
except Not_found -> []
in
Hashtbl.replace h w (i::from)
) words;
Hashtbl.fold (fun w from acc -> (w, from) :: acc) h []
let words_of_file in_file =
let str = load_file in_file in
let words = Str.split (Str.regexp "[ \r\n\t,;.?!:'/\034()]") str in
let words = uniq words in
(words)
let index_file in_file =
let words = words_of_file in_file in
let files, inv_index = get_inv_index() in
let files, i = array_push files in_file in
let inv_index = combine words i inv_index in
let se = sexp_of_t (files, inv_index) in
Sexp.save data_path se
let search_word word =
let files, inv_index = get_inv_index() in
try
let is_in = List.assoc word inv_index in
List.iter (fun i -> print_endline files.(i)) is_in
with Not_found ->
print_endline "# Not Found"
let usage() =
Printf.printf "Usage: %s \
--index-file <file.txt> / \
--search-word <some-word>\n%!" Sys.argv.(0);
exit 1
let () =
let cmd, arg = try (Sys.argv.(1), Sys.argv.(2)) with _ -> usage() in
match cmd, arg with
| "--index-file", in_file -> index_file in_file
| "--search-word", word -> search_word word
| _ -> usage()