Ppx protocol conv (de)serializers using deriving, which allows for plugable (de)serializers. Api.
This page contains an simple overview of functionality provided. More information is available in the wiki pages
The ppx supports the following features:
- records
- recursive and non-recursive types
- variants
- polymophic variants
- All primitive types (except nativeint)
The following drivers exists
Json
which serializes toYojson.Safe.t
Jsonm
which serializes toEzjsonm.value
Msgpack
which serializes toMsgpck.t
Yaml
which serializes toYaml.t
Xml_light
which serializes toXml.xml list
open Protocol_conv_json
type a = {
x: int;
y: string [@key "Y"]
z: int list [@default [2;3]]
} [@@deriving protocol ~driver:(module Json)]
type b = A of int
| B of int [@key "b"]
| C
[@@deriving protocol ~driver:(module Json)]
will generate the functions:
val a_to_json: a -> Json.t
val a_of_json_exn: Json.t -> a
val a_of_json: Json.t -> (a, exn) result
val b_to_json: a -> Json.t
val b_of_json_exn: Json.t -> a
val b_of_json: Json.t -> (b, exn) result
a_to_json { x=42; y:"really"; z:[6;7] }
Evaluates to
[ "x", `Int 42; "Y", `String "really"; "z", `List [ `Int 6; `Int 7 ] ] (* Yojson.Safe.json *)
to_protocol
deriver will generate serilisation of the
type. of_protocol
deriver generates de-serilisation of the type,
while protocol
deriver will generate both serilisation and de-serilisation functions.
Record label names can be changed using [@key <string>]
Variant and polymorphic variant constructors names can be changed using the [@name <string>]
attribute.
If a record field is not present in the input when deserialising, as default value can be
assigned using [@default <expr>]
. If the value to be serialized
matches the default value, the field will be omitted (Some drivers
allow disabling this functonality. Comparrison uses polymorphic compare, so be careful.
The ppx also handles signature, but disallows
[@key ...]
, [@default ...]
and [@name] ....
as these does not impact signatures.
Drivers specify concrete serialization and deserialization. Users of the library can elect to implement their own driver see custom drivers, or use predefined drivers:
Json
which serializes toYojson.Safe.t
Jsonm
which serializes toEzjsonm.value
Msgpack
which serializes toMsgpck.t
Yaml
which serializes toYaml.t
Xml_light
which serializes toXml.xml list
It is easy to provide custom drivers by implementing the signature:
include Protocol_conv.Runtime.Driver with
type t = ...
See the drivers
directory for examples on how to implemented new drivers.
Submissions of new drivers are more than welcome.
- Generalised algebraic datatypes
- Extensible types
- Extensible polymorphic variants