Module Bin_shape_lib.Bin_shape

type t

Shape.t are constructed by the bin_shape syntax extension from Ocaml type definitions & expressions.

There is a direct mapping from ocaml type definition syntax to the corresponding Shape.group and from ocaml type expression syntax to the corresponding Shape.t.

val sexp_of_t : t -> Ppx_sexp_conv_lib.Sexp.t

Tid.t & Vid.t are identifiers for type-constructors & type-vars. i.e. Given type 'a t = ...

module Tid : sig ... end
module Vid : sig ... end
module Location : sig ... end

Location.t is required when constructing shapes for which evaluation might fail.

module Uuid : sig ... end

Uuid.t is used by basetype and annotate.

type group

group of mutually recursive type definitions

val group : Location.t -> (Tid.t * Vid.t list * t) list -> group

This function is generative; repeated calls create distinct groups

val tuple : t list -> t
val record : (string * t) list -> t
val variant : (string * t list) list -> t
type poly_variant_row
val constr : string -> t option -> poly_variant_row
val inherit_ : Location.t -> t -> poly_variant_row
val poly_variant : Location.t -> poly_variant_row list -> t
val rec_app : Tid.t -> t list -> t

recursive apps within the current group

val top_app : group -> Tid.t -> t list -> t

apps from outside the group

val var : Location.t -> Vid.t -> t
val basetype : Uuid.t -> t list -> t

Built-in types and types with custom serialization: i.e. int,list,... To avoid accidental protocol compatibility, pass a UUID as the string argument

a = annotate s t creates a shape a distinguished, but dependent on shape t. Very much as record [(s,t)] does. But with annotate the ocaml record type does not exist.

val annotate : Uuid.t -> t -> t

Shape.Canonical.t is the result of evaluating a shape to a canonical form, and represents the shape of Ocaml types w.r.t. bin_io serialization.

The idea is that de-serialization is safe if the canonical-shape for the type produced by de-serialization is equivalent to the canonical-shape of the serialized type.

The representation is canonical, so equivalence is structural equality.

Canonical.t also provides a useful human level description of a type.

A Canonical.t can be `digested' to a Digest.t, and except for nearly impossible hash collisions, equality of the digests implies equality of canonical-shapes and hence equivalence at the Shape.t level.

Canonical.t may also be constructed with various functions: annotate, basetype, tuple, record, variant, poly_variant, fix, recurse, .. which might be used when setting up unit tests or expected shapes.

module Digest : sig ... end
module Canonical : sig ... end
val eval : t -> Canonical.t

eval t returns the canonical-shape for a shape-expression Shape.t. Type aliases are expanded, so that no Tid.t or Vid.t have significance in the resulting canonical-shape. Type-recursion, including non-regular recursion, is translated to the de-bruijn representation used in canonical-shapes.

val eval_to_digest : t -> Digest.t

eval_to_digest t returns a hash-value direct from the Shape.t, potentially avoiding the intermediate Canonical.t from being constructed. This is important as the size of a canonical-shape might be exponential in terms of the size of the shape expression. The following holds: Digest.(eval_to_digest exp = Canonical.to_digest (eval exp))

val eval_to_digest_string : t -> string

eval_to_digest_string t == Digest.to_hex (eval_to_digest t) Convenience function useful for writing unit tests.

module For_typerep : sig ... end