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
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
This function is generative; repeated calls create distinct groups
Built-in types and types with custom serialization: i.e. int,list,... To avoid accidental protocol compatibility, pass a UUID as the
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.
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.
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
eval t returns the canonical-shape for a shape-expression
Shape.t. Type aliases are expanded, so that no
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.
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