Simultaneous mapping and filtering.
Filter_mappable contains signatures and extensions for types that can be non-monadically mapped over, while simultaneously removing values.
Filter_mappable_intf contains the signatures for Filter_mappable.
include module type of Filter_mappable_intfSignatures for filter-mapping.
The basic signatures, which contain only filter_map, are Basic0 and Basic1. We also define richer signatures, S0 and S1, for which we provide functors in the main interface.
The basic signatures are Basic0, which defines filtered mapping across an arity-0 type t (with a fixed, associated element type elt), and Basic1, which defines filtered mapping across an arity-1 type 'a t (with element type 'a).
As with Traversable and Mappable, we define the basic and full signatures of filter-mappable structures in an arity-generic way, then specialise them for arity-0 and arity-1 types.
module type Generic_basic = sig ... endGeneric input shape of filter-mappable structures on either an arity-0 or arity-1 type.
module type Basic0 = sig ... endBasic signature of an arity-0 filter-mappable type.
module type Basic1 = sig ... endBasic signature of an arity-1 mappable type.
The full signatures are S0 (arity-0) and S1 (arity-1).
module type Generic = sig ... endGeneric output shape of filter-mappable structures on either an arity-0 or arity-1 type.
module type S0 = sig ... endFull signature of an arity-0 filter-mappable type.
module type S1 = sig ... endFull signature of an arity-1 mappable type.
module To_mappable0
(F : Basic0) :
Mappable.S0 with type t := F.t and type elt := F.eltTo_mappable0 lowers a filter-mappable arity-0 type to a mappable one.
module To_mappable1 (F : Basic1) : Mappable.S1 with type 'a t := 'a F.tTo_mappable1 lowers a filter-mappable arity-1 type to a mappable one.