Previous  Up  Next

Module Info

module Info: sig .. end
Info is a library for lazily constructing human-readable information as a string or sexp, with a primary use being error messages. Using Info is often preferable to sprintf or manually constructing strings because you don't have to eagerly construct the string --- you only need to pay when you actually want to display the info. which for many applications is rare. Using Info is also better than creating custom exceptions because you have more control over the format.

Info is intended to be constructed in the following style; for simple info, you write: 

Info.of_string "Unable to find file"

For info where you want to attach some content, you would write: 

Info.create "Unable to find file" filename <:sexp_of< string >>

Or even, 

    Info.create "price too big" (price, [`Max max_price])
      (<:sexp_of< float * [`Max of float] >>)

Note that an Info.t can be created from any arbritrary sexp with Info.t_of_sexp.

type t 
val to_string_hum : t -> string
might be an expensive operation
val of_string : string -> t
val of_lazy : string Lazy.t -> t
Be careful that the body of the lazy or thunk does not access mutable data, since it will only be called at an undetermined later point.
val of_thunk : (unit -> string) -> t
val create : ?here:Source_code_position0.t ->
       string -> 'a -> ('a -> Sexplib.Sexp.t) -> t
For create msg z sexp_of_z, be careful to use only immutable values for z, or be aware that z will be lazily converted to a sexp at a later point in time, which will pick up the then-current state of z.
val tag : t -> string -> t
val tag_arg : t -> string -> 'a -> ('a -> Sexplib.Sexp.t) -> t
val of_list : ?trunc_after:int -> t list -> t
val of_exn : ?backtrace:[ `Get | `This of string ] -> exn -> t
val to_exn : t -> exn
val pp : Format.formatter -> t -> unit
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

might be an expensive operation

Be careful that the body of the lazy or thunk does not access mutable data, since it will only be called at an undetermined later point.

For create msg z sexp_of_z, be careful to use only immutable values for z, or be aware that z will be lazily converted to a sexp at a later point in time, which will pick up the then-current state of z.