Source file tools.ml

open Base

let eq = Stdlib.(=)
let (=) = Stdlib.(=)
let (!=) = Stdlib.(!=)
let (>) = Stdlib.(>)
let (<) = Stdlib.(<)
let (~/) = Re2.create_exn

let range x =
  Batteries.(--) 0 x |> Batteries.List.of_enum

let sub_prefix text x = String.sub text ~pos:0 ~len:x
let sub_suffix text x = String.sub text ~pos:x ~len:(String.length text - x)
let sub_list lst start_i end_i = List.sub lst ~pos:start_i ~len:(end_i - start_i)
let sub_list_suffix lst x = List.sub lst ~pos:x ~len:(List.length lst - x)
let first_letter text = sub_prefix text 1

let string_range s start_i end_i =
  String.sub s ~pos:start_i ~len:(String.length s - end_i)

let starts_with text prefix =
  if String.length text > String.length prefix then
    let rprefix = sub_prefix text (String.length prefix) in
    rprefix = prefix
  else false

let ends_with text suffix =
  if String.length text > String.length suffix then
    let rsuffix = sub_suffix text (String.length suffix) in
    rsuffix = suffix
  else false

let remove_prefix text prefix =
  if starts_with text prefix then
    String.sub text ~pos:(String.length prefix) ~len:(String.length text - String.length prefix)
  else
    text

let remove_suffix text suffix =
  if ends_with text suffix then
    String.sub text ~pos:0 ~len:(String.length text - String.length suffix)
  else
    text

let remove_list_prefix lst prefix =
  List.sub lst ~pos:(List.length prefix) ~len:(List.length lst - List.length prefix)

type ('acc, 'curr) unfold_notifier =
  | Next of 'acc * 'curr
  | Stop of 'acc

let rec unfold acc curr func =
  match func acc curr with
  | Next (nacc, ncurr) -> unfold nacc ncurr func
  | Stop acc -> acc


type ('acc, 'curr) fold_until_notifier =
  | Forward of 'acc
  | Done of 'acc

let rec fold_until lst acc func =
  match lst with
  | hd :: tl -> (
    match func acc hd ~last:(List.length tl = 0) with
    | Forward nacc -> fold_until tl nacc func
    | Done nacc -> nacc
  )
  | _ -> acc


let nth lst index =
  match List.nth lst index with
  | Some x -> x
  | None -> Failure "Failed to get item at index" |> raise

let first lst = nth lst 0

let join_by_space lst = String.concat ~sep:" " lst
let join_by_comma lst = String.concat ~sep:", " lst
let join_by_dot lst = String.concat ~sep:"." lst
let join_by_underscore lst = String.concat ~sep:"_" lst
let join_by_arrow lst = String.concat ~sep:"->" lst
let join_by_nl lst = String.concat ~sep:"\n" lst

let join lst = String.concat ~sep:"" lst

let contains lst item =
  List.mem lst item ~equal:(=)

let unwrap_or value fallback = match value with Some v -> v | None -> fallback