Up  Next

Module Topkg.Private.Codec

module Codec: sig .. end
Topkg interprocess communication codec.

Codecs for communication between the topkg tool and topkg description files.


Decode errors


type error =
| Corrupted of (string * string)
| Version of int * int
The type for decode errors. 
val pp_error : Format.formatter -> error -> unit
pp_error ppf e prints an unspecified representation of e on ppf.
exception Error of error
Raised on decode errors.

Codecs


type 'a t
The type for codec for OCaml values of type 'a.
val v : kind:string ->
       enc:('a -> string) -> dec:(string -> 'a) -> 'a t
v kind enc dec is a codec for value identified as kind using enc to encode and dec to decode.
val kind : 'a t -> string
kind c is c's kind.
val enc : 'a t -> 'a -> string
enc c is c's encoder.
val dec : 'a t -> string -> 'a
dec c is c's decoder. The decoder
Raises Error in case of decode error
val dec_result : 'a t -> string -> 'a Topkg.result
dec c is like Topkg.Private.Codec.dec but doesn't raise. The exception is turned into an error message using Topkg.Private.Codec.pp_error.
val with_kind : string -> 'a t -> 'a t
with_kind k c is c with kind k.
val write : Topkg.fpath -> 'a t -> 'a -> unit Topkg.result
write f c v encodes value v with c to f.
val read : Topkg.fpath -> 'a t -> 'a Topkg.result
read f c reads a value with c from f.

Base type codecs


val unit : unit t
unit codecs a ().
val const : 'a -> 'a t
const v codecs the constant v.
val bool : bool t
bool codecs booleans.
val int : int t
int codecs integers.
val string : string t
string codecs strings.
val option : 'a t -> 'a option t
option el codecs el options.
val result : ok:'a t ->
       error:'b t -> ('a, 'b) Topkg.r t
result ~ok ~error codecs ok, error results.
val list : 'a t -> 'a list t
list el codecs el lists.
val pair : 'a t ->
       'b t -> ('a * 'b) t
pair c0 c1 codecs c0, c1 pairs.
val t3 : 'a t ->
       'b t ->
       'c t -> ('a * 'b * 'c) t
t3 is like Topkg.Private.Codec.pair but for triples.
val t4 : 'a t ->
       'b t ->
       'c t ->
       'd t -> ('a * 'b * 'c * 'd) t
t4 is like Topkg.Private.Codec.pair but for quadruples.
val t5 : 'a t ->
       'b t ->
       'c t ->
       'd t ->
       'e t -> ('a * 'b * 'c * 'd * 'e) t
t5 is like Topkg.Private.Codec.pair but for qintuples.
val alt : kind:string ->
       ('a -> int) -> 'a t array -> 'a t
alt tag cs codecs values by tagging them with tag and using the corresponding codec in cs.
Raises Invalid_argument if Array.length cs > 256.
val version : int -> 'a t -> 'a t
version num c versions codec c with number num. On decode a version number mismatch raises an error see Topkg.Private.Codec.error.
val view : ?kind:string ->
       ('a -> 'b) * ('b -> 'a) ->
       'b t -> 'a t
view kind t c views t as c for codecing.

Topkg types


val msg : [ `Msg of string ] t
msg codecs error messages.
val result_error_msg : 'a t -> 'a Topkg.result t
result_error_msg ok codecs ok or error message results.
val fpath : Topkg.Fpath.t t
fpath codecs files paths.
val cmd : Topkg.Cmd.t t
cmd codecs command line fragments.