Module Stdlib.Format

Pretty-printing.

This module implements a pretty-printing facility to format values within 'pretty-printing boxes'. The pretty-printer splits lines at specified break hints, and indents lines according to the box structure.

For a gentle introduction to the basics of pretty-printing using Format, read http://caml.inria.fr/resources/doc/guides/format.en.html.

You may consider this module as providing an extension to the printf facility to provide automatic line splitting. The addition of pretty-printing annotations to your regular printf format strings gives you fancy indentation and line breaks. Pretty-printing annotations are described below in the documentation of the function Format.fprintf.

You may also use the explicit pretty-printing box management and printing functions provided by this module. This style is more basic but more verbose than the concise fprintf format strings.

For instance, the sequence open_box 0; print_string "x ="; print_space (); print_int 1; close_box (); print_newline () that prints x = 1 within a pretty-printing box, can be abbreviated as printf "@[%s@ %i@]@." "x =" 1, or even shorter printf "@[x =@ %i@]@." 1.

Rule of thumb for casual users of this library:

The behavior of pretty-printing commands is unspecified if there is no open pretty-printing box. Each box open via one of the open_ functions below must be closed using close_box for proper formatting. Otherwise, some of the material printed in the boxes may not be output, or may be formatted incorrectly.

In case of interactive use, each phrase is executed in the initial state of the standard pretty-printer: after each phrase execution, the interactive system closes all open pretty-printing boxes, flushes all pending text, and resets the standard pretty-printer.

Warning: mixing calls to pretty-printing functions of this module with calls to Pervasives low level output functions is error prone.

The pretty-printing functions output material that is delayed in the pretty-printer queue and stacks in order to compute proper line splitting. In contrast, basic I/O output functions write directely in their output device. As a consequence, the output of a basic I/O function may appear before the output of a pretty-printing function that has been called before. For instance, Pervasives.print_string "<"; Format.print_string "PRETTY"; Pervasives.print_string ">"; Format.print_string "TEXT"; leads to output <>PRETTYTEXT.

Pretty-printing boxes

The pretty-printing engine uses the concepts of pretty-printing box and break hint to drive the indentation and the line splitting behavior of the pretty-printer.

Each different pretty-printing box kind introduces a specific line splitting policy:

Note that line splitting policy is box specific: the policy of a box does not rule the policy of inner boxes. For instance, if a vertical box is nested in an horizontal box, all break hints within the vertical box will split the line.

val open_box : int -> unit

open_box d opens a new compacting pretty-printing box with offset d.

Within this box, the pretty-printer prints as much as possible material on every line.

A break hint splits the line if there is no more room on the line to print the remainder of the box.

Within this box, the pretty-printer emphasizes the box structure: a break hint also splits the line if the splitting ``moves to the left'' (i.e. the new line gets an indentation smaller than the one of the current line).

This box is the general purpose pretty-printing box.

If the pretty-printer splits the line in the box, offset d is added to the current indentation.

val close_box : unit -> unit

Closes the most recently open pretty-printing box.

val open_hbox : unit -> unit

open_hbox () opens a new 'horizontal' pretty-printing box.

This box prints material on a single line.

Break hints in a horizontal box never split the line. (Line splitting may still occur inside boxes nested deeper).

val open_vbox : int -> unit

open_vbox d opens a new 'vertical' pretty-printing box with offset d.

This box prints material on as many lines as break hints in the box.

Every break hint in a vertical box splits the line.

If the pretty-printer splits the line in the box, d is added to the current indentation.

val open_hvbox : int -> unit

open_hvbox d opens a new 'horizontal/vertical' pretty-printing box with offset d.

This box behaves as an horizontal box if it fits on a single line, otherwise it behaves as a vertical box.

If the pretty-printer splits the line in the box, d is added to the current indentation.

val open_hovbox : int -> unit

open_hovbox d opens a new 'horizontal-or-vertical' pretty-printing box with offset d.

This box prints material as much as possible on every line.

A break hint splits the line if there is no more room on the line to print the remainder of the box.

If the pretty-printer splits the line in the box, d is added to the current indentation.

Formatting functions
val print_string : string -> unit

print_string s prints s in the current pretty-printing box.

val print_as : int -> string -> unit

print_as len s prints s in the current pretty-printing box. The pretty-printer formats s as if it were of length len.

val print_int : int -> unit

Print an integer in the current pretty-printing box.

val print_float : float -> unit

Print a floating point number in the current pretty-printing box.

val print_char : char -> unit

Print a character in the current pretty-printing box.

val print_bool : bool -> unit

Print a boolean in the current pretty-printing box.

Break hints

A 'break hint' tells the pretty-printer to output some space or split the line whichever way is more appropriate to the current pretty-printing box splitting rules.

Break hints are used to separate printing items and are mandatory to let the pretty-printer correctly split lines and indent items.

Simple break hints are:

Note: the notions of space and line splitting are abstract for the pretty-printing engine, since those notions can be completely redefined by the programmer. However, in the pretty-printer default setting, ``output a space'' simply means printing a space character (ASCII code 32) and ``split the line'' means printing a newline character (ASCII code 10).

val print_space : unit -> unit

print_space () emits a 'space' break hint: the pretty-printer may split the line at this point, otherwise it prints one space.

print_space is equivalent to print_break 1 0.

val print_cut : unit -> unit

print_cut () emits a 'cut' break hint: the pretty-printer may split the line at this point, otherwise it prints nothing.

print_cut is equivalent to print_break 0 0.

val print_break : int -> int -> unit

print_break nspaces offset emits a 'full' break hint: the pretty-printer may split the line at this point, otherwise it prints nspaces spaces.

If the pretty-printer splits the line, offset is added to the current indentation.

val force_newline : unit -> unit

Force a new line in the current pretty-printing box.

The pretty-printer must split the line at this point,

Not the normal way of pretty-printing, since imperative line splitting may interfere with current line counters and box size calculation. Using break hints within an enclosing vertical box is a better alternative.

val print_if_newline : unit -> unit

Execute the next formatting command if the preceding line has just been split. Otherwise, ignore the next formatting command.

Pretty-printing termination
val print_flush : unit -> unit

End of pretty-printing: resets the pretty-printer to initial state.

All open pretty-printing boxes are closed, all pending text is printed. In addition, the pretty-printer low level output device is flushed to ensure that all pending text is really displayed.

Note: never use print_flush in the normal course of a pretty-printing routine, since the pretty-printer uses a complex buffering machinery to properly indent the output; manually flushing those buffers at random would conflict with the pretty-printer strategy and result to poor rendering.

Only consider using print_flush when displaying all pending material is mandatory (for instance in case of interactive use when you want the user to read some text) and when resetting the pretty-printer state will not disturb further pretty-printing.

Warning: If the output device of the pretty-printer is an output channel, repeated calls to print_flush means repeated calls to Pervasives.flush to flush the out channel; these explicit flush calls could foil the buffering strategy of output channels and could dramatically impact efficiency.

val print_newline : unit -> unit

End of pretty-printing: resets the pretty-printer to initial state.

All open pretty-printing boxes are closed, all pending text is printed.

Equivalent to print_flush followed by a new line. See corresponding words of caution for print_flush.

Note: this is not the normal way to output a new line; the preferred method is using break hints within a vertical pretty-printing box.

Margin
val set_margin : int -> unit

set_margin d sets the right margin to d (in characters): the pretty-printer splits lines that overflow the right margin according to the break hints given. Nothing happens if d is smaller than 2. If d is too large, the right margin is set to the maximum admissible value (which is greater than 10 ^ 9).

val get_margin : unit -> int

Returns the position of the right margin.

Maximum indentation limit
val set_max_indent : int -> unit

set_max_indent d sets the maximum indentation limit of lines to d (in characters): once this limit is reached, new pretty-printing boxes are rejected to the left, if they do not fit on the current line. Nothing happens if d is smaller than 2. If d is too large, the limit is set to the maximum admissible value (which is greater than 10 ^ 9).

val get_max_indent : unit -> int

Return the maximum indentation limit (in characters).

Maximum formatting depth

The maximum formatting depth is the maximum allowed number of simultaneously open pretty-printing boxes before ellipsis.

val set_max_boxes : int -> unit

set_max_boxes max sets the maximum number of pretty-printing boxes simultaneously open.

Material inside boxes nested deeper is printed as an ellipsis (more precisely as the text returned by get_ellipsis_text ()). Nothing happens if max is smaller than 2.

val get_max_boxes : unit -> int

Returns the maximum number of pretty-printing boxes allowed before ellipsis.

val over_max_boxes : unit -> bool

Tests if the maximum number of pretty-printing boxes allowed have already been open.

Tabulation boxes

A tabulation box prints material on lines divided into cells of fixed length. A tabulation box provides a simple way to display vertical columns of left adjusted text.

This box features command set_tab to define cell boundaries, and command print_tab to move from cell to cell and split the line when there is no more cells to print on the line.

Note: printing within tabulation box is line directed, so arbitrary line splitting inside a tabulation box leads to poor rendering. Yet, controlled use of tabulation boxes allows simple printing of columns within Format.

val open_tbox : unit -> unit

open_tbox () opens a new tabulation box.

This box prints lines separated into cells of fixed width.

Inside a tabulation box, special tabulation markers defines points of interest on the line (for instance to delimit cell boundaries). Function Format.set_tab sets a tabulation marker at insertion point.

A tabulation box features specific tabulation breaks to move to next tabulation marker or split the line. Function Format.print_tbreak prints a tabulation break.

val close_tbox : unit -> unit

Closes the most recently opened tabulation box.

val set_tab : unit -> unit

Sets a tabulation marker at current insertion point.

val print_tab : unit -> unit

print_tab () emits a 'next' tabulation break hint: if not already set on a tabulation marker, the insertion point moves to the first tabulation marker on the right, or the pretty-printer splits the line and insertion point moves to the leftmost tabulation marker.

It is equivalent to print_tbreak 0 0.

val print_tbreak : int -> int -> unit

print_tbreak nspaces offset emits a 'full' tabulation break hint.

If not already set on a tabulation marker, the insertion point moves to the first tabulation marker on the right and the pretty-printer prints nspaces spaces.

If there is no next tabulation marker on the right, the pretty-printer splits the line at this point, then insertion point moves to the leftmost tabulation marker of the box.

If the pretty-printer splits the line, offset is added to the current indentation.

Ellipsis
val set_ellipsis_text : string -> unit

Set the text of the ellipsis printed when too many pretty-printing boxes are open (a single dot, ., by default).

val get_ellipsis_text : unit -> string

Return the text of the ellipsis.

Semantic tags
type tag = string

Semantic tags (or simply tags) are user's defined delimiters to associate user's specific operations to printed entities.

Common usage of semantic tags is text decoration to get specific font or text size rendering for a display device, or marking delimitation of entities (e.g. HTML or TeX elements or terminal escape sequences). More sophisticated usage of semantic tags could handle dynamic modification of the pretty-printer behavior to properly print the material within some specific tags.

In order to properly delimit printed entities, a semantic tag must be opened before and closed after the entity. Semantic tags must be properly nested like parentheses.

Tag specific operations occur any time a tag is opened or closed, At each occurrence, two kinds of operations are performed tag-marking and tag-printing:

Roughly speaking, tag-marking is commonly used to get a better rendering of texts in the rendering device, while tag-printing allows fine tuning of printing routines to print the same entity differently according to the semantic tags (i.e. print additional material or even omit parts of the output).

More precisely: when a semantic tag is opened or closed then both and successive 'tag-printing' and 'tag-marking' operations occur:

Being written directly into the output device of the formatter, semantic tag marker strings are not considered as part of the printing material that drives line splitting (in other words, the length of the strings corresponding to tag markers is considered as zero for line splitting).

Thus, semantic tag handling is in some sense transparent to pretty-printing and does not interfere with usual indentation. Hence, a single pretty-printing routine can output both simple 'verbatim' material or richer decorated output depending on the treatment of tags. By default, tags are not active, hence the output is not decorated with tag information. Once set_tags is set to true, the pretty-printer engine honors tags and decorates the output accordingly.

Default tag-marking functions behave the HTML way: tags are enclosed in "<" and ">"; hence, opening marker for tag t is "<t>" and closing marker is "</t>".

Default tag-printing functions just do nothing.

Tag-marking and tag-printing functions are user definable and can be set by calling set_formatter_tag_functions.

Semantic tag operations may be set on or off with set_tags. Tag-marking operations may be set on or off with set_mark_tags. Tag-printing operations may be set on or off with set_print_tags.

val open_tag : tag -> unit

open_tag t opens the semantic tag named t.

The print_open_tag tag-printing function of the formatter is called with t as argument; then the opening tag marker, as given by mark_open_tag t is written into the output device of the formatter.

val close_tag : unit -> unit

close_tag () closes the most recently opened semantic tag t.

The closing tag marker, as given by mark_close_tag t, is written into the output device of the formatter; then the print_close_tag tag-printing function of the formatter is called with t as argument.

val set_tags : bool -> unit

set_tags b turns on or off the treatment of semantic tags (default is off).

val set_print_tags : bool -> unit

set_print_tags b turns on or off the tag-printing operations.

val set_mark_tags : bool -> unit

set_mark_tags b turns on or off the tag-marking operation.

val get_print_tags : unit -> bool

Return the current status of tag-printing operations.

val get_mark_tags : unit -> bool

Return the current status of tag-marking operations.

Redirecting the standard formatter output
val set_formatter_out_channel : Stdlib.Pervasives.out_channel -> unit

Redirect the standard pretty-printer output to the given channel. (All the output functions of the standard formatter are set to the default output functions printing to the given channel.) set_formatter_out_channel is equivalent to pp_set_formatter_out_channel std_formatter.

val set_formatter_output_functions : (string -> int -> int -> unit) -> (unit -> unit) -> unit

set_formatter_output_functions out flush redirects the standard pretty-printer output functions to the functions out and flush.

The out function performs all the pretty-printer string output. It is called with a string s, a start position p, and a number of characters n; it is supposed to output characters p to p + n - 1 of s.

The flush function is called whenever the pretty-printer is flushed (via conversion %!, or pretty-printing indications @? or @., or using low level functions print_flush or print_newline).

val get_formatter_output_functions : unit -> (string -> int -> int -> unit) * (unit -> unit)

Return the current output functions of the standard pretty-printer.

Redefining formatter output

The Format module is versatile enough to let you completely redefine the meaning of pretty-printing output: you may provide your own functions to define how to handle indentation, line splitting, and even printing of all the characters that have to be printed!

Redefining output functions
type formatter_out_functions = {
out_string : string -> int -> int -> unit;
out_flush : unit -> unit;
out_newline : unit -> unit;
out_spaces : int -> unit;
out_indent : int -> unit;
}

The set of output functions specific to a formatter:

By default:

val set_formatter_out_functions : formatter_out_functions -> unit

set_formatter_out_functions out_funs Set all the pretty-printer output functions to those of argument out_funs,

This way, you can change the meaning of indentation (which can be something else than just printing space characters) and the meaning of new lines opening (which can be connected to any other action needed by the application at hand).

val get_formatter_out_functions : unit -> formatter_out_functions

Return the current output functions of the pretty-printer, including line splitting and indentation functions. Useful to record the current setting and restore it afterwards.

Redefining semantic tags operations
type formatter_tag_functions = {
mark_open_tag : tag -> string;
mark_close_tag : tag -> string;
print_open_tag : tag -> unit;
print_close_tag : tag -> unit;
}

The semantic tag handling functions specific to a formatter: mark versions are the 'tag-marking' functions that associate a string marker to a tag in order for the pretty-printing engine to write those markers as 0 length tokens in the output device of the formatter. print versions are the 'tag-printing' functions that can perform regular printing when a tag is closed or opened.

val set_formatter_tag_functions : formatter_tag_functions -> unit

set_formatter_tag_functions tag_funs changes the meaning of opening and closing semantic tag operations to use the functions in tag_funs.

When opening a semantic tag name t, the string t is passed to the opening tag-marking function (the mark_open_tag field of the record tag_funs), that must return the opening tag marker for that name. When the next call to close_tag () happens, the semantic tag name t is sent back to the closing tag-marking function (the mark_close_tag field of record tag_funs), that must return a closing tag marker for that name.

The print_ field of the record contains the tag-printing functions that are called at tag opening and tag closing time, to output regular material in the pretty-printer queue.

val get_formatter_tag_functions : unit -> formatter_tag_functions

Return the current semantic tag operation functions of the standard pretty-printer.

Defining formatters
type formatter

Abstract data corresponding to a pretty-printer (also called a formatter) and all its machinery.

Defining new formatters permits unrelated output of material in parallel on several output devices. All the parameters of a formatter are local to the formatter: right margin, maximum indentation limit, maximum number of pretty-printing boxes simultaneously open, ellipsis, and so on, are specific to each formatter and may be fixed independently.

For instance, given a !Buffer.t buffer b, formatter_of_buffer b returns a new formatter using buffer b as its output device. Similarly, given a !Pervasives.out_channel output channel oc, formatter_of_out_channel oc returns a new formatter using channel oc as its output device.

Alternatively, given out_funs, a complete set of output functions for a formatter, then formatter_of_out_function out_funs computes a new formatter using those functions for output.

val formatter_of_out_channel : Stdlib.out_channel -> formatter

formatter_of_out_channel oc returns a new formatter writing to the corresponding channel oc.

val std_formatter : formatter

The standard formatter to write to standard output.

It is defined as formatter_of_out_channel stdout.

val err_formatter : formatter

A formatter to to write to standard error.

It is defined as formatter_of_out_channel stderr.

val formatter_of_buffer : Stdlib.Buffer.t -> formatter

formatter_of_buffer b returns a new formatter writing to buffer b. At the end of pretty-printing, the formatter must be flushed using pp_print_flush or pp_print_newline, to print all the pending material into the buffer.

val stdbuf : Stdlib.Buffer.t

The string buffer in which str_formatter writes.

val str_formatter : formatter

A formatter to output to the stdbuf string buffer.

str_formatter is defined as formatter_of_buffer stdbuf.

val flush_str_formatter : unit -> string

Returns the material printed with str_formatter, flushes the formatter and resets the corresponding buffer.

val make_formatter : (string -> int -> int -> unit) -> (unit -> unit) -> formatter

make_formatter out flush returns a new formatter that outputs with function out, and flushes with function flush.

For instance, a formatter to the !Pervasives.out_channeloc is returned by make_formatter (!Pervasives.output oc) (fun () -> !Pervasives.flush oc).

val formatter_of_out_functions : formatter_out_functions -> formatter

formatter_of_out_functions out_funs returns a new formatter that writes with the set of output functions out_funs.

See definition of type formatter_out_functions for the meaning of argument out_funs.

Symbolic pretty-printing

Symbolic pretty-printing is pretty-printing with no low level output.

When using a symbolic formatter, all regular pretty-printing activities occur but output material is symbolic and stored in a buffer of output items. At the end of pretty-printing, flushing the output buffer allows post-processing of symbolic output before low level output operations.

type symbolic_output_item =
| Output_flush
| Output_newline
| Output_string of string
| Output_spaces of int
| Output_indent of int

(** The output items that symbolic pretty-printers will produce:

  • Output_flush: symbolic flush command.
  • Output_newline: symbolic newline command.
  • Output_string s: symbolic output for string s.
  • Output_spaces n: symbolic command to output n spaces.
  • Output_indent i: symbolic indentation of size i.
  • Since: 4.04.0

*)

type symbolic_output_buffer

The output buffer of a symbolic pretty-printer.

val make_symbolic_output_buffer : unit -> symbolic_output_buffer

make_symbolic_output_buffer () returns a fresh buffer for symbolic output.

val clear_symbolic_output_buffer : symbolic_output_buffer -> unit

clear_symbolic_output_buffer sob resets buffer sob.

val get_symbolic_output_buffer : symbolic_output_buffer -> symbolic_output_item list

get_symbolic_output_buffer sob returns the contents of buffer sob.

val flush_symbolic_output_buffer : symbolic_output_buffer -> symbolic_output_item list

flush_symbolic_output_buffer sob returns the contents of buffer sob and resets buffer sob. flush_symbolic_output_buffer sob is equivalent to let items = get_symbolic_output_buffer sob in clear_symbolic_output_buffer sob; items

val add_symbolic_output_item : symbolic_output_buffer -> symbolic_output_item -> unit

add_symbolic_output_item sob itm adds item itm to buffer sob.

val formatter_of_symbolic_output_buffer : symbolic_output_buffer -> formatter

formatter_of_symbolic_output_buffer sob returns a symbolic formatter that outputs to symbolic_output_buffersob.

Basic functions for formatters
val pp_open_hbox : formatter -> unit -> unit
val pp_open_vbox : formatter -> int -> unit
val pp_open_hvbox : formatter -> int -> unit
val pp_open_hovbox : formatter -> int -> unit
val pp_open_box : formatter -> int -> unit
val pp_close_box : formatter -> unit -> unit
val pp_open_tag : formatter -> string -> unit
val pp_close_tag : formatter -> unit -> unit
val pp_print_string : formatter -> string -> unit
val pp_print_as : formatter -> int -> string -> unit
val pp_print_int : formatter -> int -> unit
val pp_print_float : formatter -> float -> unit
val pp_print_char : formatter -> char -> unit
val pp_print_bool : formatter -> bool -> unit
val pp_print_break : formatter -> int -> int -> unit
val pp_print_cut : formatter -> unit -> unit
val pp_print_space : formatter -> unit -> unit
val pp_force_newline : formatter -> unit -> unit
val pp_print_flush : formatter -> unit -> unit
val pp_print_newline : formatter -> unit -> unit
val pp_print_if_newline : formatter -> unit -> unit
val pp_set_tags : formatter -> bool -> unit
val pp_set_print_tags : formatter -> bool -> unit
val pp_set_mark_tags : formatter -> bool -> unit
val pp_get_print_tags : formatter -> unit -> bool
val pp_get_mark_tags : formatter -> unit -> bool
val pp_set_margin : formatter -> int -> unit
val pp_get_margin : formatter -> unit -> int
val pp_set_max_indent : formatter -> int -> unit
val pp_get_max_indent : formatter -> unit -> int
val pp_set_max_boxes : formatter -> int -> unit
val pp_get_max_boxes : formatter -> unit -> int
val pp_over_max_boxes : formatter -> unit -> bool
val pp_set_ellipsis_text : formatter -> string -> unit
val pp_get_ellipsis_text : formatter -> unit -> string
val pp_set_formatter_out_channel : formatter -> Stdlib.Pervasives.out_channel -> unit
val pp_set_formatter_output_functions : formatter -> (string -> int -> int -> unit) -> (unit -> unit) -> unit
val pp_get_formatter_output_functions : formatter -> unit -> (string -> int -> int -> unit) * (unit -> unit)
val pp_set_formatter_tag_functions : formatter -> formatter_tag_functions -> unit
val pp_get_formatter_tag_functions : formatter -> unit -> formatter_tag_functions
val pp_set_formatter_out_functions : formatter -> formatter_out_functions -> unit
val pp_get_formatter_out_functions : formatter -> unit -> formatter_out_functions

These functions are the basic ones: usual functions operating on the standard formatter are defined via partial evaluation of these primitives. For instance, print_string is equal to pp_print_string std_formatter.

Convenience formatting functions.
val pp_print_list : ?pp_sep:(formatter -> unit -> unit) -> (formatter -> 'a -> unit) -> formatter -> 'a list -> unit

pp_print_list ?pp_sep pp_v ppf l prints items of list l, using pp_v to print each item, and calling pp_sep between items (pp_sep defaults to pp_print_cut). Does nothing on empty lists.

val pp_print_text : formatter -> string -> unit

pp_print_text ppf s prints s with spaces and newlines respectively printed using pp_print_space and pp_force_newline.

Formatted pretty-printing

Module Format provides a complete set of printf like functions for pretty-printing using format string specifications.

Specific annotations may be added in the format strings to give pretty-printing commands to the pretty-printing engine.

Those annotations are introduced in the format strings using the @ character. For instance, @ means a space break, @, means a cut, @[ opens a new box, and @] closes the last open box.

val fprintf : formatter -> ('aformatter, unit) Stdlib.format -> 'a

fprintf ff fmt arg1 ... argN formats the arguments arg1 to argN according to the format string fmt, and outputs the resulting string on the formatter ff.

The format string fmt is a character string which contains three types of objects: plain characters and conversion specifications as specified in the Printf module, and pretty-printing indications specific to the Format module.

The pretty-printing indication characters are introduced by a @ character, and their meanings are:

Note: To prevent the interpretation of a @ character as a pretty-printing indication, escape it with a % character. Old quotation mode @@ is deprecated since it is not compatible with formatted input interpretation of character '@'.

Example: printf "@[%s@ %d@]@." "x =" 1 is equivalent to open_box (); print_string "x ="; print_space (); print_int 1; close_box (); print_newline (). It prints x = 1 within a pretty-printing 'horizontal-or-vertical' box.

val printf : ('aformatter, unit) Stdlib.format -> 'a

Same as fprintf above, but output on std_formatter.

val eprintf : ('aformatter, unit) Stdlib.format -> 'a

Same as fprintf above, but output on err_formatter.

val sprintf : ('a, unit, string) Stdlib.format -> 'a

Same as printf above, but instead of printing on a formatter, returns a string containing the result of formatting the arguments. Note that the pretty-printer queue is flushed at the end of each call to sprintf.

In case of multiple and related calls to sprintf to output material on a single string, you should consider using fprintf with the predefined formatter str_formatter and call flush_str_formatter () to get the final result.

Alternatively, you can use Format.fprintf with a formatter writing to a buffer of your own: flushing the formatter and the buffer at the end of pretty-printing returns the desired string.

val asprintf : ('aformatter, unit, string) Stdlib.format4 -> 'a

Same as printf above, but instead of printing on a formatter, returns a string containing the result of formatting the arguments. The type of asprintf is general enough to interact nicely with %a conversions.

val ifprintf : formatter -> ('aformatter, unit) Stdlib.format -> 'a

Same as fprintf above, but does not print anything. Useful to ignore some material when conditionally printing.

Formatted Pretty-Printing with continuations.

val kfprintf : (formatter -> 'a) -> formatter -> ('bformatter, unit, 'aStdlib.format4 -> 'b

Same as fprintf above, but instead of returning immediately, passes the formatter to its first argument at the end of printing.

val ikfprintf : (formatter -> 'a) -> formatter -> ('bformatter, unit, 'aStdlib.format4 -> 'b

Same as kfprintf above, but does not print anything. Useful to ignore some material when conditionally printing.

val ksprintf : (string -> 'a) -> ('b, unit, string, 'aStdlib.format4 -> 'b

Same as sprintf above, but instead of returning the string, passes it to the first argument.

val kasprintf : (string -> 'a) -> ('bformatter, unit, 'aStdlib.format4 -> 'b

Same as asprintf above, but instead of returning the string, passes it to the first argument.

Deprecated
val bprintf : Stdlib.Buffer.t -> ('aformatter, unit) Stdlib.format -> 'a
val kprintf : (string -> 'a) -> ('b, unit, string, 'aStdlib.format4 -> 'b
val set_all_formatter_output_functions : out:(string -> int -> int -> unit) -> flush:(unit -> unit) -> newline:(unit -> unit) -> spaces:(int -> unit) -> unit
val get_all_formatter_output_functions : unit -> (string -> int -> int -> unit) * (unit -> unit) * (unit -> unit) * (int -> unit)
val pp_set_all_formatter_output_functions : formatter -> out:(string -> int -> int -> unit) -> flush:(unit -> unit) -> newline:(unit -> unit) -> spaces:(int -> unit) -> unit
val pp_get_all_formatter_output_functions : formatter -> unit -> (string -> int -> int -> unit) * (unit -> unit) * (unit -> unit) * (int -> unit)