This module implements an option ref that starts out as None, and may be set only once. If one tries to set it twice a run time error is generated.
include sig ... endval t_of_sexp : (Sexplib.Sexp.t ‑> 'a) ‑> Sexplib.Sexp.t ‑> 'a tval sexp_of_t : ('a ‑> Sexplib.Sexp.t) ‑> 'a t ‑> Sexplib.Sexp.tval bin_t : 'a Bin_prot.Type_class.t ‑> 'a t Bin_prot.Type_class.tval bin_read_t : 'a Bin_prot.Read.reader ‑> 'a t Bin_prot.Read.readerval __bin_read_t__ : 'a Bin_prot.Read.reader ‑> (Core_kernel__.Import.int ‑> 'a t) Bin_prot.Read.readerval bin_reader_t : 'a Bin_prot.Type_class.reader ‑> 'a t Bin_prot.Type_class.readerval bin_size_t : 'a Bin_prot.Size.sizer ‑> 'a t Bin_prot.Size.sizerval bin_write_t : 'a Bin_prot.Write.writer ‑> 'a t Bin_prot.Write.writerval bin_writer_t : 'a Bin_prot.Type_class.writer ‑> 'a t Bin_prot.Type_class.writerval bin_shape_t : Bin_prot.Shape.t ‑> Bin_prot.Shape.tPasses when unset.
include Core_kernel__.Import.Invariant.S1 with type a t := a tval invariant : 'a Base__.Invariant_intf.inv ‑> 'a t Base__.Invariant_intf.invval create : Core_kernel__.Import.unit ‑> 'a tval set : 'a t ‑> 'a ‑> (Core_kernel__.Import.unit, Core_kernel__.Import.string) Result.tval set_exn : 'a t ‑> 'a ‑> Core_kernel__.Import.unitval get : 'a t ‑> 'a Core_kernel__.Import.optionval get_exn : 'a t ‑> 'a