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Module type
Class type
type !_ tag =
  1. | Tag : ('variant, 'args) Tag.t -> 'variant0 tag

An existential type used to gather all the tags constituing a variant type. the 'variant parameter is the variant type, it is the same for all the constructors of that variant type. The type of the parameters might be different for each constructor and is thus existential

type !_ value =
  1. | Value : ('variant, 'args) Tag.t * 'args0 -> 'variant0 value

A similar existential constructor to _ tag but this one holds a value whose type is the arguments of the tag constructor. A value of type 'a value is a pair of (1) a value of variant type 'a along with (2) some information about the constructor within the type 'a

type 'a t

Witness of a variant type. The parameter is the type of the variant type witnessed.

val typename_of_t : 'a t -> 'a Typename.t
val length : 'a t -> int

Returns the number of tags of this variant type definition.

val tag : 'a t -> int -> 'a tag

Get the nth tag of this variant type, indexed from 0.

val is_polymorphic : 'a t -> bool

Distinguish polymorphic variants and standard variants. Typically, polymorphic variants tags starts with the ` character. Example polymorphic variant: type t = `A | `B standard variant: type t = A | B

val value : 'a t -> 'a -> 'a value

Pattern matching on a value of this variant type.

val fold : 'a t -> init:'acc -> f:('acc -> 'a tag -> 'acc) -> 'acc

folding along the tags of the variant type

val internal_use_only : 'a Variant_internal.t -> 'a t