An extension of cross references in SATySFi.
The CrossRefExt module in the cross-ref-ext/cross-ref-ext package
provides the following functions.
val register : ('a CrossRefExt-Type.t) implicit -> string -> 'a -> unit
val get : ('a CrossRefExt-Type.t) implicit -> string -> 'a option
The usage is similar to the primitives register-cross-reference and
get-cross-reference, but this package allows to register a value of
a type other than string. One can register a value of any type that
can be represented as an S-expression. See cross-ref-ext/type for
how to define a cross reference type.