Source file builtins_string.ml
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let string =
Lang.add_builtin "string" ~category:`String
~descr:"Return the representation of a value."
[
( "fields",
Lang.bool_t,
Some (Lang.bool false),
Some "Show toplevel fields around the value." );
("", Lang.univ_t (), None, None);
]
Lang.string_t
(fun p ->
let show_fields = Lang.to_bool (List.assoc "fields" p) in
let v = List.assoc "" p in
let dv = Lang.demeth v in
let show_fields = if Value.is_unit dv then true else show_fields in
let v = if show_fields then v else dv in
match v with
| String { value = s } -> Lang.string s
| v -> Lang.string (Value.to_string v))
let _ =
Lang.add_builtin "^" ~category:`String ~descr:"Concatenate strings."
[("", Lang.string_t, None, None); ("", Lang.string_t, None, None)]
Lang.string_t
(fun p ->
let s1 = Lang.to_string (Lang.assoc "" 1 p) in
let s2 = Lang.to_string (Lang.assoc "" 2 p) in
Lang.string (s1 ^ s2))
let _ =
Lang.add_builtin ~base:string "digest" ~category:`String
~descr:"Return an MD5 digest for the given string."
[("", Lang.string_t, None, None)]
Lang.string_t
(fun p ->
let data = Lang.to_string (List.assoc "" p) in
Lang.string Digest.(to_hex (string data)))
let _ =
Lang.add_builtin ~base:string "concat" ~category:`String
~descr:"Concatenate strings."
[
("separator", Lang.string_t, Some (Lang.string ""), None);
("", Lang.list_t Lang.string_t, None, None);
]
Lang.string_t
(fun p ->
let sep = Lang.to_string (List.assoc "separator" p) in
let l = Lang.to_list (List.assoc "" p) in
let l = List.map Lang.to_string l in
Lang.string (String.concat sep l))
let split ~encoding s =
let buf = Buffer.create 1 in
let to_string add c =
Buffer.clear buf;
add buf c;
Buffer.contents buf
in
let get =
match encoding with
| `Ascii -> fun pos -> (to_string Buffer.add_char (String.get s pos), 1)
| `Utf8 ->
fun pos ->
let d = String.get_utf_8_uchar s pos in
if not (Uchar.utf_decode_is_valid d) then
failwith "Decoding failed!";
( to_string Buffer.add_utf_8_uchar (Uchar.utf_decode_uchar d),
Uchar.utf_decode_length d )
in
let len = String.length s in
let rec f chars pos =
if pos = len then List.rev chars
else (
let char, len = get pos in
f (char :: chars) (pos + len))
in
f [] 0
let default_encoding = ref `Utf8
let encoding_option =
( "encoding",
Lang.nullable_t Lang.string_t,
Some Lang.null,
Some
"Encoding used to split characters. Should be one of: `\"utf8\"` or \
`\"ascii\"`" )
let get_encoding p =
match Lang.to_valued_option Lang.to_string (List.assoc "encoding" p) with
| None -> ("utf8", !default_encoding)
| Some "utf8" -> ("utf8", `Utf8)
| Some "ascii" -> ("ascii", `Ascii)
| _ ->
Runtime_error.raise ~pos:(Lang.pos p) ~message:"Invalid encoding!"
"invalid"
let _ =
Lang.add_builtin ~base:string "chars" ~category:`String
~descr:"Split string into characters. Raises `error.invalid` on errors."
[encoding_option; ("", Lang.string_t, None, None)]
(Lang.list_t Lang.string_t)
(fun p ->
let enc, encoding = get_encoding p in
let s = Lang.to_string (List.assoc "" p) in
try Lang.list (List.map Lang.string (split ~encoding s))
with _ ->
Runtime_error.raise ~pos:(Lang.pos p)
~message:
(Printf.sprintf "String cannot be split using encoding `\"%s\"`!"
enc)
"invalid")
let _ =
Lang.add_builtin ~base:string "length" ~category:`String
~descr:
"Return the string's length using the given encoding. Raises \
`error.invalid` on errors."
[encoding_option; ("", Lang.string_t, None, None)]
Lang.int_t
(fun p ->
let enc, encoding = get_encoding p in
let s = Lang.to_string (List.assoc "" p) in
try Lang.int (List.length (split ~encoding s))
with _ ->
Runtime_error.raise ~pos:(Lang.pos p)
~message:
(Printf.sprintf "String cannot be split using encoding `\"%s\"`!"
enc)
"invalid")
let _ =
Lang.add_builtin ~base:string "nth" ~category:`String
~descr:
"Retrieve a character in a string. Raises `error.not_found` if character \
does not exist."
~examples:
[
{|
c = string.nth("abcde", 2)
print(c) # should print 99 which is the ascii code for "c"
|};
]
[
("", Lang.string_t, None, Some "String to look into.");
("", Lang.int_t, None, Some "Index of the character.");
]
Lang.int_t
(fun p ->
try
let s = Lang.to_string (Lang.assoc "" 1 p) in
let n = Lang.to_int (Lang.assoc "" 2 p) in
Lang.int (int_of_char s.[n])
with _ ->
Runtime_error.raise ~pos:(Lang.pos p)
~message:"string.nth: character not found!" "not_found")
let _ =
Lang.add_builtin ~base:string "char" ~category:`String
~descr:"Create a string with one character."
[("", Lang.int_t, None, Some "Code of the character.")]
Lang.string_t
(fun p ->
List.assoc "" p |> Lang.to_int |> Char.chr |> String.make 1 |> Lang.string)
let string_escape =
Lang.add_builtin ~base:string "escape" ~category:`String
~descr:
"Escape special characters in an string. By default, the string is \
assumed to be `\"utf8\"` encoded and is escaped following JSON and \
javascript specification."
[
( "special_char",
Lang.nullable_t
(Lang.fun_t
[(false, "encoding", Lang.string_t); (false, "", Lang.string_t)]
Lang.bool_t),
Some Lang.null,
Some
"Return `true` if the given character (passed as a string) should be \
escaped. Defaults to control characters for `\"utf8\"` and control \
characters and any character above `\\x7E` (non-printable \
characters) for `\"ascii\"`." );
( "escape_char",
Lang.nullable_t
(Lang.fun_t
[(false, "encoding", Lang.string_t); (false, "", Lang.string_t)]
Lang.string_t),
Some Lang.null,
Some
"Function used to escape a character. Defaults to `\\xxx` octal \
notation for `\"ascii\"` and `\\uxxxx` hexadecimal notation for \
`\"utf8\"`." );
( "encoding",
Lang.nullable_t Lang.string_t,
Some Lang.null,
Some
"One of: `\"ascii\"` or `\"utf8\"`. If `null`, `utf8` is tried first \
and `ascii` is used as a fallback if this fails." );
("", Lang.string_t, None, None);
]
Lang.string_t
(fun p ->
let s = Lang.to_string (List.assoc "" p) in
let encoding = List.assoc "encoding" p in
let encoding : [ `Default | `Ascii | `Utf8 ] =
match Lang.to_valued_option Lang.to_string encoding with
| None -> `Default
| Some "ascii" -> `Ascii
| Some "utf8" -> `Utf8
| Some _ ->
raise
(Error.Invalid_value
( encoding,
"Encoding should be one of: \"ascii\" or \"utf8\"." ))
in
let exec encoding =
let encoding_string =
match encoding with `Utf8 -> "utf8" | `Ascii -> "ascii"
in
let special_char =
match (Lang.to_option (List.assoc "special_char" p), encoding) with
| Some f, _ ->
fun s ofs len ->
Lang.to_bool
(Lang.apply f
[
("encoding", Lang.string encoding_string);
("", Lang.string (String.sub s ofs len));
])
| None, `Ascii -> Lang_string.ascii_special_char
| None, `Utf8 -> Lang_string.utf8_special_char
in
let escape_char =
match (Lang.to_option (List.assoc "escape_char" p), encoding) with
| Some f, _ ->
fun s ofs len ->
Lang.to_string
(Lang.apply f
[
("encoding", Lang.string encoding_string);
("", Lang.string (String.sub s ofs len));
])
| None, `Ascii -> Lang_string.escape_hex_char
| None, `Utf8 -> Lang_string.escape_utf8_char ~strict:false
in
let next =
match encoding with
| `Ascii -> Lang_string.ascii_next
| `Utf8 -> Lang_string.utf8_next
in
try
Lang.string
(Lang_string.escape_string
(Lang_string.escape ~special_char ~escape_char ~next)
s)
with _ ->
let bt = Printexc.get_raw_backtrace () in
Runtime_error.raise ~bt ~pos:(Lang.pos p)
~message:
(Printf.sprintf "Error while escaping %s string.%s"
(match encoding with `Utf8 -> "utf8" | `Ascii -> "ascii")
(if encoding <> `Ascii then
" If you are not sure about the string's encoding, you \
should use `\"ascii\"` as this encoding never fails."
else ""))
"string"
in
match encoding with
| `Default -> ( try exec `Utf8 with _ -> exec `Ascii)
| (`Ascii | `Utf8) as encoding -> exec encoding)
let _ =
Lang.add_builtin ~base:string_escape "all"
~descr:
"Escape each character in the given string using a specific escape \
sequence."
~category:`String
[
( "format",
Lang.string_t,
Some (Lang.string "utf8"),
Some "Escape format. One of: `\"octal\"`, `\"hex\"` or `\"utf8\"`." );
("", Lang.string_t, None, None);
]
Lang.string_t
(fun p ->
let format = List.assoc "format" p in
let escape_char, next =
match Lang.to_string format with
| "octal" -> (Lang_string.escape_octal_char, Lang_string.ascii_next)
| "hex" -> (Lang_string.escape_hex_char, Lang_string.ascii_next)
| "utf8" ->
(Lang_string.escape_utf8_char ~strict:false, Lang_string.utf8_next)
| _ ->
raise
(Error.Invalid_value
( format,
"Format should be one of: `\"octal\"`, `\"hex\"` or \
`\"utf8\"`." ))
in
let s = Lang.to_string (List.assoc "" p) in
Lang.string
(Lang_string.escape_string
(Lang_string.escape
~special_char:(fun _ _ _ -> true)
~escape_char ~next)
s))
let _ =
Lang.add_builtin ~base:string_escape "special_char"
~descr:
"Default function to detect characters to escape. See `string.escape` \
for more details."
~category:`String
[
( "encoding",
Lang.string_t,
Some (Lang.string "utf8"),
Some "One of: `\"ascii\"` or `\"utf8\"`." );
("", Lang.string_t, None, None);
]
Lang.bool_t
(fun p ->
let s = Lang.to_string (List.assoc "" p) in
let len = String.length s in
let encoding = List.assoc "encoding" p in
match Lang.to_string encoding with
| "ascii" -> Lang.bool (Lang_string.ascii_special_char s 0 len)
| "utf8" -> Lang.bool (Lang_string.utf8_special_char s 0 len)
| _ ->
raise
(Error.Invalid_value
(encoding, "Encoding should be one of: \"ascii\" or \"utf8\".")))
let _ =
Lang.add_builtin ~base:string "unescape"
~descr:"This function is the inverse of `string.escape`." ~category:`String
[("", Lang.string_t, None, None)]
Lang.string_t
(fun p ->
let s = Lang.to_string (List.assoc "" p) in
Lang.string (Lang_string.unescape_string s))
let _ =
Lang.add_builtin ~base:string "sub" ~category:`String
~descr:
"Get a substring of a string. Returns \"\" if no such substring exists."
[
("", Lang.string_t, None, None);
( "start",
Lang.int_t,
None,
Some
"Return a sub string starting at this position. First position is 0."
);
encoding_option;
( "length",
Lang.int_t,
None,
Some "Return a sub string of `length` characters." );
]
Lang.string_t
(fun p ->
let start = Lang.to_int (List.assoc "start" p) in
let len = Lang.to_int (List.assoc "length" p) in
let _, encoding = get_encoding p in
let string = Lang.to_string (List.assoc "" p) in
let s =
match encoding with
| `Ascii -> (
try String.sub string start len with Invalid_argument _ -> "")
| `Utf8 -> (
try
let chars = split ~encoding string in
if List.length chars < len + start then ""
else
String.concat ""
(List.filteri
(fun pos _ -> start <= pos && pos < start + len)
chars)
with _ -> "")
in
Lang.string s)
let _ =
Lang.add_builtin ~base:string "index" ~category:`String
~descr:
"Index where a substring occurs in a string. The function returns `-1` \
if the substring is not present"
[
("substring", Lang.string_t, None, Some "Substring to look for.");
("", Lang.string_t, None, Some "String in which to look.");
]
Lang.int_t
(fun p ->
let t = List.assoc "substring" p |> Lang.to_string in
let s = List.assoc "" p |> Lang.to_string in
let ans =
let m = String.length t in
let n = String.length s in
let ans = ref (-1) in
try
for i = 0 to n - m do
if String.sub s i m = t then (
ans := i;
raise Exit)
done;
-1
with Exit -> !ans
in
Lang.int ans)
let _ =
Lang.add_builtin ~base:string "case" ~category:`String
~descr:"Convert a string to lower or upper case."
[
( "lower",
Lang.bool_t,
Some (Lang.bool true),
Some "Convert to lower case if true and uppercase otherwise." );
("", Lang.string_t, None, None);
]
Lang.string_t
(fun p ->
let lower = Lang.to_bool (List.assoc "lower" p) in
let string = Lang.to_string (List.assoc "" p) in
Lang.string
(if lower then String.lowercase_ascii string
else String.uppercase_ascii string))
let _ =
Lang.add_builtin ~base:string "trim" ~category:`String
~descr:"Return a string without leading and trailing whitespace."
[("", Lang.string_t, None, None)]
Lang.string_t
(fun p -> Lang.string (String.trim (Lang.to_string (List.assoc "" p))))
let _ =
Lang.add_builtin ~base:string "capitalize" ~category:`String
~descr:
"Return a string with the first character set to upper case \
(capitalize), or to lower case (uncapitalize)."
[
( "capitalize",
Lang.bool_t,
Some (Lang.bool true),
Some "Capitalize if true, uncapitalize otherwise" );
( "space_sensitive",
Lang.bool_t,
Some (Lang.bool true),
Some "Capitalize each space separated sub-string." );
("", Lang.string_t, None, None);
]
Lang.string_t
(fun p ->
let cap = Lang.to_bool (List.assoc "capitalize" p) in
let space_sensitive = Lang.to_bool (List.assoc "space_sensitive" p) in
let string = Lang.to_string (List.assoc "" p) in
let f s =
if cap then String.capitalize_ascii s else String.uncapitalize_ascii s
in
Lang.string
(if space_sensitive then (
let l = String.split_on_char ' ' string in
let l = List.map f l in
String.concat " " l)
else f string))
let _ =
Lang.add_builtin ~base:string "hex_of_int" ~category:`String
~descr:"Hexadecimal representation of an integer."
[
( "pad",
Lang.int_t,
Some (Lang.int 0),
Some
"Minimum length in digits (pad on the left with zeros in order to \
reach it)." );
("", Lang.int_t, None, None);
]
Lang.string_t
(fun p ->
let pad = Lang.to_int (List.assoc "pad" p) in
let n = Lang.to_int (List.assoc "" p) in
let s = Printf.sprintf "%x" n in
let s =
let len = String.length s in
if len < pad then String.make (pad - len) '0' ^ s else s
in
Lang.string s)
(** Data conversions. *)
let () =
let register_tt doc name category func ~needs_default in_type in_value
out_value out_type =
let raise_doc =
if needs_default then
[%string
{| Raises `error.failure("%{doc}")` if conversion fails and default is `null`|}]
else ""
in
ignore
(Lang.add_builtin name ~category
~descr:[%string {|Convert %{doc}.%{raise_doc}|}]
([("", in_type, None, None)]
@
if needs_default then
[("default", Lang.nullable_t out_type, Some Lang.null, None)]
else [])
out_type
(fun p ->
try out_value (func (in_value (List.assoc "" p)))
with _ -> (
try Option.get (Lang.to_option (List.assoc "default" p))
with _ ->
Runtime_error.raise ~pos:(Lang.pos p) ~message:name "failure")))
in
let register_tts name func out_value out_type =
register_tt ~needs_default:true ("a string to a " ^ name)
(name ^ "_of_string") `String func Lang.string_t Lang.to_string out_value
out_type
in
let register_tti name func out_value out_type =
register_tt ~needs_default:false ("an int to a " ^ name) (name ^ "_of_int")
`Math func Lang.int_t Lang.to_int out_value out_type
in
let register_ttf name func out_value out_type =
register_tt ~needs_default:false ("a float to a " ^ name)
(name ^ "_of_float") `Math func Lang.float_t Lang.to_float out_value
out_type
in
register_tts "int" int_of_string (fun v -> Lang.int v) Lang.int_t;
register_tts "float" float_of_string (fun v -> Lang.float v) Lang.float_t;
register_tts "bool" bool_of_string (fun v -> Lang.bool v) Lang.bool_t;
register_tti "float" float_of_int (fun v -> Lang.float v) Lang.float_t;
register_tti "bool" (fun v -> v = 1) (fun v -> Lang.bool v) Lang.bool_t;
register_ttf "int" int_of_float (fun v -> Lang.int v) Lang.int_t;
register_ttf "bool" (fun v -> v = 1.) (fun v -> Lang.bool v) Lang.bool_t
let _ =
Lang.add_builtin ~base:string "float" ~category:`String
~descr:"String representation of a float."
[
( "decimal_places",
Lang.nullable_t Lang.int_t,
Some Lang.null,
Some "Number of decimal places." );
("", Lang.float_t, None, None);
]
Lang.string_t
(fun p ->
let dp =
List.assoc "decimal_places" p
|> Lang.to_option |> Option.map Lang.to_int
in
let x = List.assoc "" p |> Lang.to_float in
let s =
match dp with
| Some d -> Printf.sprintf "%.*f" d x
| None -> Utils.string_of_float x
in
Lang.string s)
let _ =
Lang.add_builtin ~base:string "make" ~category:`String
~descr:"Create a string of a given length using the given character."
[
( "char_code",
Lang.int_t,
Some (Lang.int (Char.code ' ')),
Some "Character code." );
("", Lang.int_t, None, Some "String length.");
]
Lang.string_t
(fun p ->
let n = Lang.to_int (List.assoc "" p) in
if n < 0 then
Runtime_error.raise ~pos:(Lang.pos p) ~message:"Invalid string length!"
"invalid";
let c =
try Char.chr (Lang.to_int (List.assoc "char_code" p))
with _ ->
Runtime_error.raise ~pos:(Lang.pos p)
~message:"Invalid character code!" "invalid"
in
Lang.string (String.make n c))
let _ =
Lang.add_builtin ~base:string "id" ~category:`String
~descr:"Generate an identifier with given operator name."
[("", Lang.string_t, None, Some "Operator name.")]
Lang.string_t
(fun p ->
let name = List.assoc "" p |> Lang.to_string in
Lang.string (Lang_string.generate_id name))
let string_base64 = Lang.add_module ~base:string "base64"
let _ =
Lang.add_builtin ~base:string_base64 "decode" ~category:`String
~descr:"Decode a Base64 encoded string."
[("", Lang.string_t, None, None)]
Lang.string_t
(fun p ->
let string = Lang.to_string (List.assoc "" p) in
try Lang.string (Lang_string.decode64 string)
with _ ->
Runtime_error.raise ~pos:(Lang.pos p) ~message:"Invalid base64 string!"
"invalid")
let _ =
Lang.add_builtin ~base:string_base64 "encode" ~category:`String
~descr:"Encode a string in Base64."
[("", Lang.string_t, None, None)]
Lang.string_t
(fun p ->
let string = Lang.to_string (List.assoc "" p) in
Lang.string (Lang_string.encode64 string))
let url = Modules.url
let _ =
Lang.add_builtin ~base:url "decode" ~category:`String
~descr:"Decode an encoded url (e.g. \"%20\" becomes \" \")."
[
("plus", Lang.bool_t, Some (Lang.bool true), None);
("", Lang.string_t, None, None);
]
Lang.string_t
(fun p ->
let plus = Lang.to_bool (List.assoc "plus" p) in
let string = Lang.to_string (List.assoc "" p) in
Lang.string (Lang_string.url_decode ~plus string))
let _ =
Lang.add_builtin ~base:url "encode" ~category:`String
~descr:"Encode an url (e.g. \" \" becomes \"%20\")."
[
("plus", Lang.bool_t, Some (Lang.bool true), None);
("", Lang.string_t, None, None);
]
Lang.string_t
(fun p ->
let plus = Lang.to_bool (List.assoc "plus" p) in
let string = Lang.to_string (List.assoc "" p) in
Lang.string (Lang_string.url_encode ~plus string))