One typically obtains a Source_code_position.t using a _here_ expression, which is implemented by the pa_here preprocessor.
type t = Lexing.position
type t_hum = t
include Comparable.S with type t := t
include Hashable.S with type t := t
val to_string : t -> string
to_string t converts t to the form "FILE:LINE:COL".
val t_of_sexp : Sexplib.Sexp.t -> t
val sexp_of_t : t -> Sexplib.Sexp.t
val bin_t : t Bin_prot.Type_class.t
val bin_read_t : t Bin_prot.Read.reader
val __bin_read_t__ : (int -> t) Bin_prot.Read.reader
val bin_reader_t : t Bin_prot.Type_class.reader
val bin_size_t : t Bin_prot.Size.sizer
val bin_write_t : t Bin_prot.Write.writer
val bin_writer_t : t Bin_prot.Type_class.writer
val sexp_of_t_hum : t_hum -> Sexplib.Sexp.t
val compare_t_hum : t_hum -> t_hum -> int
val bin_t_hum : t_hum Bin_prot.Type_class.t
val bin_read_t_hum : t_hum Bin_prot.Read.reader
val __bin_read_t_hum__ : (int -> t_hum) Bin_prot.Read.reader
val bin_reader_t_hum : t_hum Bin_prot.Type_class.reader
val bin_size_t_hum : t_hum Bin_prot.Size.sizer
val bin_write_t_hum : t_hum Bin_prot.Write.writer
val bin_writer_t_hum : t_hum Bin_prot.Type_class.writer