Use Create(B) to make a record scanning module with basis B.
type field = | Required : {nym : 'a Cf_type.nym;scan : 'a B.Form.t B.Scan.t;} -> fieldA field of the named type is required.
*)| Optional : {nym : 'a Cf_type.nym;scan : 'a B.Form.t B.Scan.t;} -> fieldA field of the named type is optional.
*)| Default : {nym : 'a Cf_type.nym;scan : 'a B.Form.t B.Scan.t;default : 'a;} -> fieldA field of the named type is optional with a default value.
*)Field descriptor type. A schema contains a map of indexes to values of this type, which indicate whether the field is required or optional, along with a description of the type of the field value and a scanner for values of that type.
Use schema fields to make a record schema for scanning records according to fields. If ~ignore:(n, p) is provided, then as many as n unrecognized fields are scanned according to p and their values are discarded.
val range : schema -> int * intUse range schema to get the minimum and maximum number of fields that can be processed by scanning with schema.
Use scan schema to scan a record according to schema producing a pack value containing all the values in the record.
val unpack : pack -> B.Index.t -> 'a Cf_type.nym -> 'a B.Form.tUse unpack pack index nym to unpack from pack the value for the field named by index with the type nym.
Note well: fields with Optional type in the schema are packed with the corresponding Cf_type.Option type nym, and the unpacked value is either Some v if the field is present in the scanned record, or None if the field was not present.