Data.Keyval make :
field_name:string ->
enc:'a Twine.encoder ->
dec:'a Twine.decoder ->
pp:'a Imandrakit_common.Fmt.printer ->
unit ->
'a tGenerate a new key. Each call will produce a new distinct key.
val find : string -> any optionval pp : 'a t -> 'a Imandrakit_common.Fmt.printer