Module Format


module Format = struct ... end 
Types
formatter Abstract data type corresponding to a pretty-printer and all its machinery. Defining new pretty-printers permits the output of material in parallel on several channels. Parameters of the pretty-printer are local to the pretty-printer: margin, maximum indentation limit, maximum number of boxes simultaneously opened, ellipsis, and so on, are specific to each pretty-printer and may be fixed independently. Given an output channel oc, a new formatter writing to that channel is obtained by calling formatter_of_out_channel oc. Alternatively the make_formatter function allocates a new formatter with explicit output and flushing functions (convenient to output material to strings for instance).
Abstract

Simple values
std_formatter formatter
The standard formatter used by the formatting functions above. It is defined as formatter_of_out_channel stdout.
err_formatter formatter
A formatter to use with formatting functions below for output to standard error. It is defined as formatter_of_out_channel stderr.
stdbuf Buffer.t
The string buffer in which str_formatter writes.
str_formatter formatter
A formatter to use with formatting functions below for output to the stdbuf string buffer.

Functions

open_box : int -> unit
open_box d opens a new pretty-printing box with offset d. This box is the general purpose pretty-printing box. Material in this box is displayed ``horizontal or vertical'': break hints inside the box may lead to a new line, if there is no more room on the line to print the remainder of the box, or if a new line may lead to a new indentation (demonstrating the indentation of the box). When a new line is printed in the box, d is added to the current indentation.

close_box : unit -> unit
Close the most recently opened pretty-printing box.

print_string : string -> unit
print_string str prints str in the current box.

print_as : int -> string -> unit
print_as len str prints str in the current box. The pretty-printer formats str as if it were of length len.

print_int : int -> unit
Print an integer in the current box.

print_float : float -> unit
Print a floating point number in the current box.

print_char : char -> unit
Print a character in the current box.

print_bool : bool -> unit
Print an boolean in the current box.

print_space : unit -> unit
print_space () is used to separate items (typically to print a space between two words). It indicates that the line may be split at this point. It either prints one space or splits the line. It is equivalent to print_break 1 0.

print_cut : unit -> unit
print_cut () is used to mark a good break position. It indicates that the line may be split at this point. It either prints nothing or splits the line. This allows line splitting at the current point, without printing spaces or adding indentation. It is equivalent to print_break 0 0.

print_break : int -> int -> unit
Insert a break hint in a pretty-printing box. print_break nspaces offset indicates that the line may be split (a newline character is printed) at this point, if the contents of the current box does not fit on the current line. If the line is split at that point, offset is added to the current indentation. If the line is not split, nspaces spaces are printed.

print_flush : unit -> unit
Flush the pretty printer: all opened boxes are closed, and all pending text is displayed.

print_newline : unit -> unit
Equivalent to print_flush followed by a new line.

force_newline : unit -> unit
Force a newline in the current box. Not the normal way of pretty-printing, you should prefer break hints.

print_if_newline : unit -> unit
Execute the next formatting command if the preceding line has just been split. Otherwise, ignore the next formatting command.

set_margin : int -> unit
set_margin d sets the value of the right margin to d (in characters): this value is used to detect line overflows that leads to split lines. Nothing happens if d is smaller than 2 or bigger than 999999999.

get_margin : unit -> int
Return the position of the right margin.

set_max_indent : int -> unit
set_max_indent d sets the value of the maximum indentation limit to d (in characters): once this limit is reached, boxes are rejected to the left, if they do not fit on the current line. Nothing happens if d is smaller than 2 or bigger than 999999999.

get_max_indent : unit -> int
Return the value of the maximum indentation limit (in characters).

set_max_boxes : int -> unit
set_max_boxes max sets the maximum number of boxes simultaneously opened. 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 not greater than 1.

get_max_boxes : unit -> int
Return the maximum number of boxes allowed before ellipsis.

over_max_boxes : unit -> bool
Test the maximum number of boxes allowed have already been opened.

open_hbox : unit -> unit
open_hbox () opens a new pretty-printing box. This box is ``horizontal'': the line is not split in this box (new lines may still occur inside boxes nested deeper).

open_vbox : int -> unit
open_vbox d opens a new pretty-printing box with offset d. This box is ``vertical'': every break hint inside this box leads to a new line. When a new line is printed in the box, d is added to the current indentation.

open_hvbox : int -> unit
open_hvbox d opens a new pretty-printing box with offset d. This box is ``horizontal-vertical'': it behaves as an ``horizontal'' box if it fits on a single line, otherwise it behaves as a ``vertical'' box. When a new line is printed in the box, d is added to the current indentation.

open_hovbox : int -> unit
open_hovbox d opens a new pretty-printing box with offset d. This box is ``horizontal or vertical'': break hints inside this box may lead to a new line, if there is no more room on the line to print the remainder of the box. When a new line is printed in the box, d is added to the current indentation.

open_tbox : unit -> unit
Open a tabulation box.

close_tbox : unit -> unit
Close the most recently opened tabulation box.

print_tbreak : int -> int -> unit
Break hint in a tabulation box. print_tbreak spaces offset moves the insertion point to the next tabulation (spaces being added to this position). Nothing occurs if insertion point is already on a tabulation mark. If there is no next tabulation on the line, then a newline is printed and the insertion point moves to the first tabulation of the box. If a new line is printed, offset is added to the current indentation.

set_tab : unit -> unit
Set a tabulation mark at the current insertion point.

print_tab : unit -> unit
print_tab () is equivalent to print_tbreak (0,0).

set_ellipsis_text : string -> unit
Set the text of the ellipsis printed when too many boxes are opened (a single dot, ., by default).

get_ellipsis_text : unit -> string
Return the text of the ellipsis.

set_formatter_out_channel : Pervasives.out_channel -> unit
Redirect the pretty-printer output to the given channel.

set_formatter_output_functions : out:(buf:string -> pos:int -> len:int -> unit) ->
flush:(unit -> unit) -> unit

set_formatter_output_functions out flush redirects the pretty-printer output to the functions out and flush. The out function performs the pretty-printer 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 using print_flush or print_newline.

get_formatter_output_functions : unit -> (buf:string -> pos:int -> len:int -> unit) * (unit -> unit)
Return the current output functions of the pretty-printer.

set_all_formatter_output_functions : out:(buf:string -> pos:int -> len:int -> unit) ->
flush:(unit -> unit) -> newline:(unit -> unit) -> space:(int -> unit) -> unit

set_all_formatter_output_functions out flush outnewline outspace redirects the pretty-printer output to the functions out and flush as described in set_formatter_output_functions. In addition, the pretty-printer function that outputs a newline is set to the function outnewline and the function that outputs indentation spaces is set to the function outspace. This way, you can change the meaning of indentation (which can be something else than just printing a space character) and the meaning of new lines opening (which can be connected to any other action needed by the application at hand). The two functions outspace and outnewline are normally connected to out and flush: respective default values for outspace and outnewline are out (String.make n ' ') 0 n and out "\n" 0 1.

get_all_formatter_output_functions : unit ->
(buf:string -> pos:int -> len:int -> unit) * (unit -> unit) *
(unit -> unit) * (int -> unit)

Return the current output functions of the pretty-printer, including line breaking and indentation functions.

formatter_of_out_channel : Pervasives.out_channel -> formatter
formatter_of_out_channel oc returns a new formatter that writes to the corresponding channel oc.

formatter_of_buffer : Buffer.t -> formatter
formatter_of_buffer b returns a new formatter writing to buffer b. As usual, the formatter has to be flushed at the end of pretty printing, using pp_print_flush or pp_print_newline, to display all the pending material. In this case the buffer is also flushed using Buffer.flush.

flush_str_formatter : unit -> string
Returns the material printed with str_formatter, flushes the formatter and reset the corresponding buffer. str_formatter is defined as formatter_of_buffer stdbuf.

make_formatter : out:(buf:string -> pos:int -> len:int -> unit) ->
flush:(unit -> unit) -> formatter

make_formatter out flush returns a new formatter that writes according to the output function out, and the flushing function flush. Hence, a formatter to out channel oc is returned by make_formatter (output oc) (fun () -> flush oc).

pp_open_hbox : formatter -> unit -> unit

pp_open_vbox : formatter -> int -> unit

pp_open_hvbox : formatter -> int -> unit

pp_open_hovbox : formatter -> int -> unit

pp_open_box : formatter -> int -> unit

pp_close_box : formatter -> unit -> unit

pp_print_string : formatter -> string -> unit

pp_print_as : formatter -> int -> string -> unit

pp_print_int : formatter -> int -> unit

pp_print_float : formatter -> float -> unit

pp_print_char : formatter -> char -> unit

pp_print_bool : formatter -> bool -> unit

pp_print_break : formatter -> int -> int -> unit

pp_print_cut : formatter -> unit -> unit

pp_print_space : formatter -> unit -> unit

pp_force_newline : formatter -> unit -> unit

pp_print_flush : formatter -> unit -> unit

pp_print_newline : formatter -> unit -> unit

pp_print_if_newline : formatter -> unit -> unit

pp_open_tbox : formatter -> unit -> unit

pp_close_tbox : formatter -> unit -> unit

pp_print_tbreak : formatter -> int -> int -> unit

pp_set_tab : formatter -> unit -> unit

pp_print_tab : formatter -> unit -> unit

pp_set_margin : formatter -> int -> unit

pp_get_margin : formatter -> unit -> int

pp_set_max_indent : formatter -> int -> unit

pp_get_max_indent : formatter -> unit -> int

pp_set_max_boxes : formatter -> int -> unit

pp_get_max_boxes : formatter -> unit -> int

pp_over_max_boxes : formatter -> unit -> bool

pp_set_ellipsis_text : formatter -> string -> unit

pp_get_ellipsis_text : formatter -> unit -> string

pp_set_formatter_out_channel : formatter -> Pervasives.out_channel -> unit

pp_set_formatter_output_functions : formatter ->
out:(buf:string -> pos:int -> len:int -> unit) ->
flush:(unit -> unit) -> unit


pp_get_formatter_output_functions : formatter ->
unit -> (buf:string -> pos:int -> len:int -> unit) * (unit -> unit)


pp_set_all_formatter_output_functions : formatter ->
out:(buf:string -> pos:int -> len:int -> unit) ->
flush:(unit -> unit) -> newline:(unit -> unit) -> space:(int -> unit) -> unit


pp_get_all_formatter_output_functions : formatter ->
unit ->
(buf:string -> pos:int -> len:int -> unit) * (unit -> unit) *
(unit -> unit) * (int -> unit)

The basic functions to use with formatters. 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.

fprintf : formatter -> ('a, formatter, unit) format -> 'a
fprintf ff format arg1 ... argN formats the arguments arg1 to argN according to the format string format, and outputs the resulting string on the formatter ff. The format 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. The pretty-printing indication characters are introduced by a @ character, and their meanings are: Example: printf "@[%s@ %d@]" "x =" 1 is equivalent to open_box (); print_string "x ="; print_space (); print_int 1; close_box (). It prints x = 1 within a pretty-printing box.

bprintf : Buffer.t -> ('b, formatter, unit) format -> 'b
Same as fprintf, but instead of printing on a formatter, writes into the buffer argument.

printf : ('c, formatter, unit) format -> 'c
Same as fprintf, but output on std_formatter.

eprintf : ('d, formatter, unit) format -> 'd
Same as fprintf, but output on err_formatter.

sprintf : ('e, unit, string) format -> 'e
Same as printf, but instead of printing on a formatter, return a string containing the result of formatting the arguments.