Module B0_std.Fmt

Textual formatters.

Helpers for dealing with Format.

Standard outputs

val stdout : Stdlib.Format.formatter

stdout outputs to standard output.

val stderr : Stdlib.Format.formatter

stderr outputs to standard error.


val pf : Stdlib.Format.formatter -> ('a, Stdlib.Format.formatter, unit) Stdlib.format -> 'a

pf is Format.fprintf.

val pr : ('a, Stdlib.Format.formatter, unit) Stdlib.format -> 'a

pf is Format.printf.

val epr : ('a, Stdlib.Format.formatter, unit) Stdlib.format -> 'a

epr is Format.eprintf.

val str : ('a, Stdlib.Format.formatter, unit, string) Stdlib.format4 -> 'a

str is Format.asprintf.

val kpf : (Stdlib.Format.formatter -> 'a) -> Stdlib.Format.formatter -> ('b, Stdlib.Format.formatter, unit, 'a) Stdlib.format4 -> 'b

kpf is Format.kfprintf.

val kstr : (string -> 'a) -> ('b, Stdlib.Format.formatter, unit, 'a) Stdlib.format4 -> 'b

kstr is Format.kasprintf.

val failwith : ('b, Stdlib.Format.formatter, unit, 'a) Stdlib.format4 -> 'b

failwith fmt ... is kstr failwith fmt ...

val failwith_notrace : ('b, Stdlib.Format.formatter, unit, 'a) Stdlib.format4 -> 'b

failwith_notrace is like failwith but Failure is raised with raise_notrace.

val invalid_arg : ('b, Stdlib.Format.formatter, unit, 'a) Stdlib.format4 -> 'b

invalid_arg fmt ... is kstr invalid_arg fmt ...

val error : ('b, Stdlib.Format.formatter, unit, ('a, string) Stdlib.result) Stdlib.format4 -> 'b

error fmt ... is kstr (fun s -> Error s) fmt ...


type 'a t = Stdlib.Format.formatter -> 'a -> unit

The type for formatter of values of type 'a.

val flush : 'a t

flush has the effect of Format.pp_print_flush.

val flush_nl : 'a t

flush_nl has the effect of Format.pp_print_newline.

val nop : 'a t

nop formats nothing.

val any : (unit, Stdlib.Format.formatter, unit) Stdlib.format -> 'a t

any fmt formats any value with fmt.

val using : ('a -> 'b) -> 'b t -> 'a t

using f pp ppf v is pp ppf (f v).


val cut : 'a t

cut has the effect of Format.pp_print_cut.

val sp : 'a t

sp has the effect of Format.pp_print_space.

val sps : int -> 'a t

sps n has the effect of Format.pp_print_break n 0.

val comma : 'a t

comma is Fmt.any ",@ ".

val semi : 'a t

semi is Fmt.any ";@ ".


val iter : ?sep:unit t -> (('a -> unit) -> 'b -> unit) -> 'a t -> 'b t

iter ~sep iter pp_elt formats the iterations of iter over a value using pp_elt. Iterations are separated by sep (defaults to cut).

val iter_bindings : ?sep:unit t -> (('a -> 'b -> unit) -> 'c -> unit) -> ('a * 'b) t -> 'c t

iter_bindings ~sep iter pp_binding formats the iterations of iter over a value using pp_binding. Iterations are separated by sep (defaults to cut).

val append : 'a t -> 'a t -> 'a t

append pp_v0 pp_v1 ppf v is pp_v0 ppf v; pp_v1 ppf v.

val (++) : 'a t -> 'a t -> 'a t

( ++ ) is append.

val concat : ?sep:unit t -> 'a t list -> 'a t

concat ~sep pps concatenates the formatters pps separating them with sep (defaults to cut).


val box : ?indent:int -> 'a t -> 'a t

box ~indent pp ppf wraps pp in a horizontal or vertical box. Break hints that lead to a new line add indent to the current indentation (defaults to 0).

val hbox : 'a t -> 'a t

hbox is like box but is a horizontal box: the line is not split in this box (but may be in sub-boxes).

val vbox : ?indent:int -> 'a t -> 'a t

vbox is like box but is a vertical box: every break hint leads to a new line which adds indent to the current indentation (default to 0).

val hvbox : ?indent:int -> 'a t -> 'a t

hvbox is like box but is either hbox if its fits on a single line or vbox otherwise.

val hovbox : ?indent:int -> 'a t -> 'a t

hovbox is a condensed box, see Format.pp_open_hovbox.


val parens : 'a t -> 'a t

parens pp_v ppf is pf "@[<1>(%a)@]" pp_v.

val brackets : 'a t -> 'a t

brackets pp_v ppf is pf "@[<1>[%a]@]" pp_v.

val braces : 'a t -> 'a t

braces pp_v ppf is pf "@[<1>{%a}@]" pp_v.

val quote : ?mark:string -> 'a t -> 'a t

quote ~mark pp_v ppf is pf "@[<1>@<1>%s%a@<1>%s@]" mark pp_v mark, mark defaults to "\"", it is always counted as spanning as single column (this allows for UTF-8 encoded marks).


val id : 'a -> 'a

id is

val field : ?label:string t -> ?sep:unit t -> string -> ('b -> 'a) -> 'a t -> 'b t

field ~label ~sep l prj pp_v pretty prints a labelled field value as pf "@[<1>%a%a%a@]" label l sep () (using prj pp_v). label defaults to tty_string [`Yellow] and sep to any ":@ ".

val record : ?sep:unit t -> 'a t list -> 'a t

record ~sep fields pretty-prints a value using the concatenation of fields, separated by sep (defaults to cut) and framed in a vertical box.

Stdlib types

Formatters for structures give full control to the client over the formatting process and do not wrap the formatted structures with boxes.

val bool : bool t

bool is Format.pp_print_bool.

val int : int t

int is Format.pp_print_int.

val uint32 : int32 t

uint32 is pf ppf "%lu".

val int32 : int32 t

int32 is pf ppf "%ld".

val int64 : int64 t

int64 is pf ppf "%Ld".

val uint64 : int64 t

uint64 is pf ppf "%Lu".

val float : float t

float is pf ppf "%g".

val char : char t

char is Format.pp_print_char.

val string : string t

string is Format.pp_print_string.

val sys_signal : int t

sys_signal formats an OCaml signal number as a C POSIX constant or "SIG(%d)" if the signal number is unknown.

val backtrace : Stdlib.Printexc.raw_backtrace t

backtrace formats a backtrace.

val exn : exn t

exn formats an exception.

val exn_backtrace : (exn * Stdlib.Printexc.raw_backtrace) t

exn_backtrace formats an exception backtrace.

val pair : ?sep:unit t -> 'a t -> 'b t -> ('a * 'b) t

pair ~sep pp_fst pp_snd formats a pair. The first and second projection are formatted using pp_fst and pp_snd and are separated by sep (defaults to cut).

val option : ?none:unit t -> 'a t -> 'a option t

option ~none pp_v formats an option. The Some case uses pp_v and None uses none (defaults to nop).

val none : unit t

none is any "<none>".

val list : ?empty:unit t -> ?sep:unit t -> 'a t -> 'a list t

list ~sep pp_v formats list elements. Each element of the list is formatted in order with pp_v. Elements are separated by sep (defaults to cut). If the list is empty, this is empty (defaults to nop).

val array : ?empty:unit t -> ?sep:unit t -> 'a t -> 'a array t

array ~sep pp_v formats array elements. Each element of the array is formatted in in order with pp_v. Elements are seperated by sep (defaults to cut). If the array is empty this is empty (defauls to nop).


val si_size : scale:int -> string -> int t

si_size ~scale unit formats a non negative integer representing unit unit at scale 10scale * 3, depending on its magnitude, using power of 3 SI prefixes (i.e. all of them except deca, hector, deci and centi). Only US-ASCII characters are used, µ (10-6) is written using u.

scale indicates the scale 10scale * 3 an integer represents, for example -1 for munit (10-3), 0 for unit (100), 1 for kunit (103); it must be in the range [-8;8] or Invalid_argument is raised.

Except at the maximal yotta scale always tries to show three digits of data with trailing fractional zeros omited. Rounds towards positive infinity (over approximates).

val byte_size : int t

byte_size is si_size ~scale:0 "B".

val uint64_ns_span : int64 t

uint64_ns_span formats an unsigned nanosecond time span according to its magnitude using SI prefixes on seconds and accepted non-SI units. Years are counted in Julian years (365.25 SI-accepted days) as defined by the International Astronomical Union (IAU). Only US-ASCII characters are used (us is used for µs).

Text and lines

val text : string t

text is Format.pp_print_text.

val lines : string t

lines formats lines by replacing newlines ('\n') in the string with calls to Format.pp_force_newline.

val truncated : max:int -> string t

truncated ~max formats a string using at most max characters. If the string doesn't fit, it is truncated and ended with three consecutive dots which do count towards max.

HCI fragments

val and_enum : ?empty:unit t -> 'a t -> 'a list t

and_enum ~empty pp_v ppf l formats l according to its length.

  • 0, formats empty (defaults to nop).
  • 1, formats the element with pp_v.
  • 2, formats "%a and %a" with the list elements
  • n, formats "%a, ... and %a" with the list elements
val or_enum : ?empty:unit t -> 'a t -> 'a list t

or_enum is like and_enum but uses "or" instead of "and".

val did_you_mean : 'a t -> 'a list t

did_you_mean pp_v formats "Did you mean %a ?" with or_enum if the list is non-empty and nop otherwise.

val must_be : 'a t -> 'a list t

must_be pp_v formats "Must be %a." with or_enum if the list is non-empty and nop otherwise.

val unknown : kind:unit t -> 'a t -> 'a t

unknown ~kind pp_v formats "Unknown %a %a." kind () pp_v.

val unknown' : kind:unit t -> 'a t -> hint:('a t -> 'a list t) -> ('a * 'a list) t

unknown ~kind pp_v ~hint (v, hints) formats unknown followed by a space and hint pp_v hints if hints is non-empty.

ANSI TTY styling

val set_tty_cap : ?cap:Tty.cap -> unit -> unit

set_tty_cap ?cap () sets the global TTY formatting capabilities to cap if specified and to Tty.(cap (of_fd Unix.stdout)) otherwise. . Affects the output of tty_str and tty.

val tty_cap : unit -> Tty.cap

tty_cap () is the global styling capability.

val tty_string : list -> string t

tty_string styles ppf s prints s on ppf according to styles and the value of tty_styling_cap.

val tty : list -> 'a t -> 'a t

tty styles pp_v ppf v prints v with pp_v on ppf according to styles and the value of tty_styling_cap.

val code : 'a t -> 'a t

code is tty `Bold.