package bos
Library
Module
Module type
Parameter
Class
Class type
include module type of struct include Fmt end
Standard outputs
Formatting
pf
is Format.fprintf
.
str
is Format.asprintf
.
Note. When using str
utf_8
and style_renderer
are always respectively set to true
and `None
. See also str_like
.
val kpf :
(Stdlib.Format.formatter -> 'a) ->
Stdlib.Format.formatter ->
('b, Stdlib.Format.formatter, unit, 'a) Stdlib.format4 ->
'b
kpf
is Format.kfprintf
.
kstr
is like str
but continuation based.
val str_like :
Stdlib.Format.formatter ->
('a, Stdlib.Format.formatter, unit, string) Stdlib.format4 ->
'a
str_like ppf
is like str
except its utf_8
and style_renderer
settings are those of ppf
.
with_buffer ~like b
is a formatter whose utf_8
and style_renderer
settings are copied from those of like
(if provided).
failwith
is kstr failwith
, raises Stdlib.Failure
with a pretty-printed string argument.
failwith_notrace
is like failwith
but raises with raise_notrace
.
invalid_arg
is kstr invalid_arg
, raises Stdlib.Invalid_argument
with a pretty-printed string argument.
error fmt ...
is kstr (fun s -> Error s) fmt ...
val error_msg :
('b, Stdlib.Format.formatter, unit, ('a, [> `Msg of string ]) Stdlib.result)
Stdlib.format4 ->
'b
error_msg fmt ...
is kstr (fun s -> Error (`Msg s)) fmt ...
Formatters
val flush : 'a t
flush
has the effect of Format.pp_print_flush
val nop : 'a t
nop
formats nothing.
val any : (unit, Stdlib.Format.formatter, unit) Stdlib.format -> 'a t
any fmt ppf v
formats any value with the constant format fmt
.
fmt fmt ppf
is pf ppf fmt
. If fmt
is used with a single non-constant formatting directive, generates a value of type t
.
Separators
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
.
Sequencing
concat ~sep pps
formats a value using the formaters pps
and separting each format with sep
(defaults to cut
).
iter ~sep iter pp_elt
formats the iterations of iter
over a value using pp_elt
. Iterations are separated by sep
(defaults to cut
).
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
).
Boxes
box ~indent pp ppf
wraps pp
in a pretty-printing box. The box tries to print as much as possible on every line, while emphasizing the box structure (see Format.pp_open_box
). Break hints that lead to a new line add indent
to the current indentation (defaults to 0
).
hbox
is like box
but is a horizontal box: the line is not split in this box (but may be in sub-boxes). See Format.pp_open_hbox
.
vbox
is like box
but is a vertical box: every break hint leads to a new line which adds indent
to the current indentation (defaults to 0
). See Format.pp_open_vbox
.
Brackets
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).
Records
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 styled `Yellow string
and sep
to any ":@ "
.
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. Use the Dump
module to quickly format values for inspection.
val bool : bool t
bool
is Format.pp_print_bool
.
val int : int t
int ppf
is pf ppf "%d"
.
val nativeint : nativeint t
nativeint ppf
is pf ppf "%nd"
.
val int32 : int32 t
int32 ppf
is pf ppf "%ld"
.
val int64 : int64 t
int64 ppf
is pf ppf "%Ld"
.
val uint : int t
uint ppf
is pf ppf "%u"
.
val unativeint : nativeint t
unativeint ppf
is pf ppf "%nu"
.
val uint32 : int32 t
uint32 ppf
is pf ppf "%lu"
.
val uint64 : int64 t
uint64 ppf
is pf ppf "%Lu"
.
val float : float t
float ppf
is pf ppf "%g".
val float_dfrac : int -> float t
float_dfrac d
rounds the float to the d
th decimal fractional digit and formats the result with "%g"
. Ties are rounded towards positive infinity. The result is only defined for 0 <= d <= 16
.
val float_dsig : int -> float t
float_dsig d
rounds the normalized decimal significand of the float to the d
th decimal fractional digit and formats the result with "%g"
. Ties are rounded towards positive infinity. The result is NaN on infinities and only defined for 0 <= d <= 16
.
Warning. The current implementation overflows on large d
and floats.
val char : char t
char
is Format.pp_print_char
.
val string : string t
string
is Format.pp_print_string
.
val buffer : Stdlib.Buffer.t t
buffer
formats a Buffer.t
value's current contents.
val exn : exn t
exn
formats an exception.
val exn_backtrace : (exn * Stdlib.Printexc.raw_backtrace) t
exn_backtrace
formats an exception backtrace.
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
).
option ~none pp_v
formats an optional value. The Some
case uses pp_v
and None
uses none
(defaults to nop
).
result ~ok ~error
formats a result value using ok
for the Ok
case and error
for the Error
case.
hashtbl ~sep pp_binding
formats the bindings of a hash table. Each binding is formatted with pp_binding
and bindings are separated by sep
(defaults to cut
). If the hash table has multiple bindings for a given key, all bindings are formatted, with the most recent binding first. If the hash table is empty, this is nop
.
module Dump = Fmt.Dump
Formatters for inspecting OCaml values.
Magnitudes
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 bi_byte_size : int t
bi_byte_size
formats a byte size according to its magnitude using binary prefixes up to pebi bytes (215).
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
).
Binary data
The type for random addressable, sized sequences. Each (n, f)
represents the sequence f 0, ..., f (n - 1)
.
ascii ~w ~subst ()
formats character sequences by printing characters in the printable US-ASCII range ([0x20];[0x7E]
) as is, and replacing the rest with subst
(defaults to fmt "."
). w
causes the output to be right padded to the size of formatting at least w
sequence elements (defaults to 0
).
octets ~w ~sep ()
formats character sequences as hexadecimal digits. It prints groups of successive characters of unspecified length together, separated by sep
(defaults to sp
). w
causes the output to be right padded to the size of formatting at least w
sequence elements (defaults to 0
).
addresses pp
formats sequences by applying pp
to consecutive subsequences of length w
(defaults to 16). addr
formats subsequence offsets (defaults to an unspecified hexadecimal format).
hex ~w ()
formats character sequences as traditional hex dumps, matching the output of xxd and forcing line breaks after every w
characters (defaults to 16).
Words, paragraphs, text and lines
Note. These functions only work on US-ASCII strings and/or with newlines ('\n'
). If you are dealing with UTF-8 strings or different kinds of line endings you should use the pretty-printers from Uuseg_string
.
White space. White space is one of the following US-ASCII characters: space ' '
(0x20
), tab '\t'
(0x09
), newline '\n'
(0x0A
), vertical tab (0x0B
), form feed (0x0C
), carriage return '\r'
(0x0D
).
val words : string t
words
formats words by suppressing initial and trailing white space and replacing consecutive white space with a single Format.pp_print_space
.
val paragraphs : string t
paragraphs
formats paragraphs by suppressing initial and trailing spaces and newlines, replacing blank lines (a line made only of white space) by a two Format.pp_force_newline
and remaining consecutive white space with a single Format.pp_print_space
.
val text : string t
text
formats text by respectively replacing spaces and newlines in the string with Format.pp_print_space
and Format.pp_force_newline
.
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
.
val text_loc : ((int * int) * (int * int)) t
text_loc
formats a line-column text range according to GNU conventions.
HCI fragments
one_of ~empty pp_v ppf l
formats according to the length of l
0
, formatsempty
(defaults tonop
).1
, formats the element withpp_v
.2
, formats"either %a or %a"
with the list elementsn
, formats"one of %a, ... or %a"
with the list elements
did_you_mean ~pre kind ~post pp_v
formats a faulty value v
of kind kind
and a list of hints
that v
could have been mistaken for.
pre
defaults to unit "Unknown"
, post
to nop
they surround the faulty value before the "did you mean" part as follows "%a %s
%a%a." pre () kind pp_v v post ()
. If hints
is empty no "did you mean" part is printed.
Conditional UTF-8 formatting
Note. Since Format
is not UTF-8 aware using UTF-8 output may derail the pretty printing process. Use the pretty-printers from Uuseg_string
if you are serious about UTF-8 formatting.
if_utf_8 pp_u pp ppf v
is:
pp_u ppf v
ifutf_8 ppf
istrue
.pp ppf v
otherwise.
utf_8 ppf
is true
if UTF-8 output is enabled on ppf
. If set_utf_8
hasn't been called on ppf
this is true
.
set_utf_8 ppf b
enables or disables conditional UTF-8 formatting on ppf
.
Styled formatting
The type for colors.
type style = [
| `None
| `Bold
| `Faint
| `Italic
| `Underline
| `Reverse
| `Fg of [ color | `Hi of color ]
| `Bg of [ color | `Hi of color ]
| color
]
The type for styles:
`None
resets the styling.`Bold
,`Faint
,`Italic
,`Underline
and`Reverse
are display attributes.`Fg _
is the foreground color or high-intensity color on`Hi _
.`Bg _
is the foreground color or high-intensity color on`Hi _
.#color
is the foreground colour, deprecated use`Fg #color
instead.
Style rendering control
The type for style renderers.
`Ansi_tty
, renders styles using ANSI escape sequences.`None
, styled rendering has no effect.
val style_renderer : Stdlib.Format.formatter -> style_renderer
style_renderer ppf
is the style renderer used by ppf
. If set_style_renderer
has never been called on ppf
this is `None
.
val set_style_renderer : Stdlib.Format.formatter -> style_renderer -> unit
set_style_renderer ppf r
sets the style renderer of ppf
to r
.
Converting with string value converters
val of_to_string : ('a -> string) -> 'a t
of_to_string f ppf v
is string ppf (f v)
.
val to_to_string : 'a t -> 'a -> string
to_to_string pp_v v
is strf "%a" pp_v v
.
Deprecated
val strf_like :
Stdlib.Format.formatter ->
('a, Stdlib.Format.formatter, unit, string) Stdlib.format4 ->
'a
val always : (unit, Stdlib.Format.formatter, unit) Stdlib.format -> 'a t
val unit : (unit, Stdlib.Format.formatter, unit) Stdlib.format -> unit t
Naming conventions
Given a type ty
use:
pp_ty
for a pretty printer that provides full control to the client and does not wrap the formatted value in an enclosing box. See these examples.pp_dump_ty
for a pretty printer that provides little control over the pretty-printing process, wraps the rendering in an enclosing box and tries as much as possible to respect the OCaml syntax. These pretty-printers should make it easy to inspect and understand values of the given type, they are mainly used for quick printf debugging and/or toplevel interaction. See these examples.
If you are in a situation where making a difference between dump_ty
and pp_ty
doesn't make sense then use pp_ty
.
For a type ty
that is the main type of the module (the "M.t
" convention) drop the suffix, that is simply use M.pp
and M.pp_dump
.