Source file read.ml
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open Core_kernel
open! Int.Replace_polymorphic_compare
exception Bad_csv_formatting = Parse_state.Bad_csv_formatting
module On_invalid_row = struct
type 'a t =
int String.Map.t
-> string Append_only_buffer.t
-> exn
-> [ `Skip | `Yield of 'a | `Raise of exn ]
let raise _ _ exn = `Raise exn
let skip _ _ _ = `Skip
let create = Fn.id
end
module Header = Header
module Builder = struct
type _ t =
| Column : int -> string t
| Header : string -> string t
| Header_opt : string -> string option t
| Return : 'a -> 'a t
| Apply : ('b -> 'a) t * 'b t -> 'a t
| Map : ('b -> 'a) * 'b t -> 'a t
| Map2 : ('b -> 'c -> 'a) * 'b t * 'c t -> 'a t
| Both : 'a t * 'b t -> ('a * 'b) t
| Lambda : (int String.Map.t -> string Append_only_buffer.t -> 'a) -> 'a t
module T = struct
let return x = Return x
let apply f x =
match f with
| Return f -> Map (f, x)
| Map (f, w) -> Map2 (f, w, x)
| _ -> Apply (f, x)
;;
let map x ~f =
match x with
| Return x -> Return (f x)
| _ -> Map (f, x)
;;
let ( >>| ) t f = map t ~f
let map2 x y ~f =
match x, y with
| Return x, Return y -> Return (f x y)
| _ -> Map2 (f, x, y)
;;
let map3 x y z ~f =
match x, y, z with
| Return x, Return y, Return z -> Return (f x y z)
| _ -> Apply (Map2 (f, x, y), z)
;;
let all ts = List.fold_right ts ~init:(return []) ~f:(map2 ~f:(fun x xs -> x :: xs))
let all_unit ts = map ~f:ignore (all ts)
let both x y = Both (x, y)
let ( <*> ) = apply
let ( *> ) u v = return (fun () y -> y) <*> u <*> v
let ( <* ) u v = return (fun x () -> x) <*> u <*> v
module Applicative_infix = struct
let ( <*> ) = ( <*> )
let ( *> ) = ( *> )
let ( <* ) = ( <* )
let ( >>| ) = ( >>| )
end
end
include T
let at_index i ~f = Map (f, Column i)
let at_header h ~f = Map (f, Header h)
let at_header_opt h ~f = Map (f, Header_opt h)
let lambda f = Lambda f
module Open_on_rhs_intf = struct
module type S = Read_intf.Open_on_rhs with type 'a t := 'a t
end
module Let_syntax = struct
include T
include Applicative_infix
module Let_syntax = struct
include T
module Open_on_rhs = struct
let at_index = at_index
let at_header = at_header
let at_header_opt = at_header_opt
end
end
end
module Without_headers = struct
type 'a t =
| Column : int -> string t
| Return : 'a -> 'a t
| Apply : ('b -> 'a) t * 'b t -> 'a t
| Map : ('b -> 'a) * 'b t -> 'a t
| Map2 : ('b -> 'c -> 'a) * 'b t * 'c t -> 'a t
| Both : ('a t * 'b t) -> ('a * 'b) t
| Lambda :
(int String.Map.t -> string Append_only_buffer.t -> 'a) * int String.Map.t
-> 'a t
let get_fields_used t =
let open Option.Let_syntax in
let rec fields : type a. a t -> Int.Set.t option = function
| Return _ -> Some Int.Set.empty
| Column i -> Some (Int.Set.singleton i)
| Apply (f, x) ->
let%bind f = fields f in
let%map x = fields x in
Set.union f x
| Map (_, x) -> fields x
| Map2 (_, x, y) ->
let%bind x = fields x in
let%map y = fields y in
Set.union x y
| Both (x, y) ->
let%bind x = fields x in
let%map y = fields y in
Set.union x y
| Lambda _ -> None
in
fields t
;;
let build t =
let rec build' : type a. a t -> string Append_only_buffer.t -> a =
fun t row ->
match t with
| Return x -> x
| Column i -> Append_only_buffer.nth_exn row i
| Apply (f, x) -> (build' f row) (build' x row)
| Map (f, x) -> f (build' x row)
| Map2 (f, x, y) -> f (build' x row) (build' y row)
| Both (x, y) -> build' x row, build' y row
| Lambda (f, header_map) -> f header_map row
in
let fields_used = get_fields_used t in
match fields_used with
| None -> build' t, None
| Some fields_used ->
let fields_used = Set.to_list fields_used in
let mapping =
List.mapi fields_used ~f:(fun i field_index -> field_index, i)
|> Int.Map.of_alist_exn
in
let rec remap : type a. a t -> a t =
fun t ->
match t with
| Column i -> Column (Map.find_exn mapping i)
| Return x -> Return x
| Apply (f, x) -> Apply (remap f, remap x)
| Map (f, x) -> Map (f, remap x)
| Map2 (f, x, y) -> Map2 (f, remap x, remap y)
| Both (x, y) -> Both (remap x, remap y)
| Lambda _ -> t
in
build' (remap t), Some (Array.of_list fields_used)
;;
end
let build ~header_map t =
let rec transform : type a. a t -> a Without_headers.t = function
| Return x -> Without_headers.Return x
| Column i -> Without_headers.Column i
| Header h ->
(match String.Map.find_exn header_map h with
| index -> Without_headers.Column index
| exception (Not_found_s _ | Caml.Not_found) ->
raise_s
[%message "Header not found" (h : string) (header_map : int String.Map.t)])
| Header_opt h ->
(match String.Map.find_exn header_map h with
| index -> Without_headers.Map (Option.some, Column index)
| exception (Not_found_s _ | Caml.Not_found) -> Without_headers.Return None)
| Apply (f, x) -> Without_headers.Apply (transform f, transform x)
| Map (f, x) -> Without_headers.Map (f, transform x)
| Map2 (f, x, y) -> Without_headers.Map2 (f, transform x, transform y)
| Both (x, y) -> Without_headers.Both (transform x, transform y)
| Lambda f -> Without_headers.Lambda (f, header_map)
in
let transformed = transform t in
Without_headers.build transformed
;;
end
include Builder
module Parse_header = struct
exception Header_parsed of string array * int
type t =
{ state : unit Parse_state.t
; transform : string array -> int String.Map.t
}
let is_at_beginning_of_row t = Parse_state.is_at_beginning_of_row t.state
let header_map_opt header_row =
Array.foldi header_row ~init:String.Map.empty ~f:(fun i map header ->
match header with
| None -> map
| Some header -> Map.set map ~key:header ~data:i)
;;
let header_map header_row = header_map_opt (Array.map ~f:Option.some header_row)
let require_header required_headers' csv_headers' =
let required_headers = String.Set.of_list required_headers' in
let csv_headers = String.Set.of_array csv_headers' in
let missing = Set.diff required_headers csv_headers in
if not (Set.is_empty missing)
then
raise_s
[%message
"Header specified in `Require not present in csv document"
(required_headers : String.Set.t)
(csv_headers : String.Set.t)
(missing : String.Set.t)];
header_map csv_headers'
;;
let create' ?strip ?sep ?quote transform =
let f offset () row =
raise (Header_parsed (Append_only_buffer.to_array row, offset))
in
{ state = Parse_state.create ?strip ?sep ?quote ~fields_used:None ~init:() ~f ()
; transform
}
;;
let create ?strip ?sep ?quote ?(header = `No) () =
match header with
| `No -> Second String.Map.empty
| `Add headers -> Second (header_map (Array.of_list headers))
| `Yes ->
let f headers = header_map headers in
First (create' ?strip ?sep ?quote f)
| `Require headers ->
let f csv_headers = require_header headers csv_headers in
First (create' ?strip ?sep ?quote f)
| `Replace headers ->
let f _ = header_map (Array.of_list headers) in
First (create' ?strip ?sep ?quote f)
| `Transform f ->
let f headers = header_map (Array.of_list (f (Array.to_list headers))) in
First (create' ?strip ?sep ?quote f)
| `Filter_map f ->
let f headers = header_map_opt (Array.of_list (f (Array.to_list headers))) in
First (create' ?strip ?sep ?quote f)
;;
let input_string t ~len input =
try First { t with state = Parse_state.input_string t.state ~len input } with
| Header_parsed (row, offset) ->
Second (t.transform row, String.sub input ~pos:offset ~len:(len - offset))
;;
let input t ~len input =
try First { t with state = Parse_state.input t.state ~len input } with
| Header_parsed (row, offset) ->
Second (t.transform row, Bytes.To_string.sub input ~pos:offset ~len:(len - offset))
;;
end
module Expert = struct
module Append_only_buffer = Append_only_buffer
module Parse_state = Parse_state
module Builder = Builder
module Parse_header = Parse_header
let create_parse_state
?strip
?sep
?quote
?(on_invalid_row = On_invalid_row.raise)
~header_map
builder
~init
~f
=
let row_to_'a, fields_used = Builder.build ~header_map builder in
let f _offset init row =
try f init (row_to_'a row) with
| exn ->
(match on_invalid_row header_map row exn with
| `Yield x -> f init x
| `Skip -> init
| `Raise exn -> raise exn)
in
Parse_state.create ?strip ?sep ?quote ~fields_used ~init ~f ()
;;
let manual_parse_state ?strip ?sep ?quote header_map =
Parse_state.create
?strip
?sep
?quote
~fields_used:None
~init:(Append_only_buffer.create ())
~f:(fun _ queue row ->
Append_only_buffer.append queue (Row.Expert.of_buffer header_map row);
queue)
()
;;
let manual_parse_data parse_state input =
let parse_state =
match input with
| `Eof -> Parse_state.finish parse_state
| `Data s -> Parse_state.input_string parse_state s
in
let queue = Parse_state.acc parse_state in
let result = Append_only_buffer.to_list queue in
Append_only_buffer.lax_clear queue;
Second parse_state, result
;;
let manual_parse_header ?strip ?sep ?quote header_state input =
let input =
match input with
| `Eof -> ""
| `Data s -> s
in
match Parse_header.input_string header_state ~len:(String.length input) input with
| First header_state -> First header_state, []
| Second (header_map, input) ->
let state = manual_parse_state ?strip ?sep ?quote header_map in
manual_parse_data state (`Data input)
;;
let create_partial ?strip ?sep ?quote ?header () =
let state =
Parse_header.create ?strip ?sep ?quote ?header ()
|> Either.Second.map ~f:(manual_parse_state ?strip ?sep ?quote)
|> ref
in
let parse_chunk input =
let state', results =
match !state with
| First state -> manual_parse_header ?strip ?sep state input
| Second state -> manual_parse_data state input
in
state := state';
results
in
stage parse_chunk
;;
end
let fold_string ?strip ?sep ?quote ?header ?on_invalid_row builder ~init ~f csv_string =
match
match Parse_header.create ?strip ?sep ?quote ?header () with
| Second header_map -> Some (header_map, csv_string)
| First header_parse ->
(match
Parse_header.input_string
header_parse
~len:(String.length csv_string)
csv_string
with
| First _ ->
if String.is_empty csv_string
then None
else
raise_s
[%message
"String ended mid-header row"
(csv_string : string)
(sep : char option)
(header : Header.t option)]
| Second (header_map, csv_string) -> Some (header_map, csv_string))
with
| None -> init
| Some (header_map, csv_string) ->
Parse_state.input_string
(Expert.create_parse_state
?strip
?sep
?quote
?on_invalid_row
~header_map
builder
~init
~f)
csv_string
|> Parse_state.finish
|> Parse_state.acc
;;
let list_of_string ?strip ?sep ?quote ?header ?on_invalid_row builder csv_string =
fold_string
?strip
?sep
?quote
?header
?on_invalid_row
builder
csv_string
~init:(Append_only_buffer.create ())
~f:(fun queue row ->
Append_only_buffer.append queue row;
queue)
|> Append_only_buffer.to_list
;;
module Row = struct
type 'a builder_t = 'a t
include Row
let builder = lambda Row.Expert.of_buffer
end