428 lines
21 KiB
OCaml
428 lines
21 KiB
OCaml
(***********************************************************************)
|
|
(* *)
|
|
(* Objective Caml *)
|
|
(* *)
|
|
(* Pierre Weis, projet Cristal, INRIA Rocquencourt *)
|
|
(* *)
|
|
(* Copyright 1996 Institut National de Recherche en Informatique et *)
|
|
(* en Automatique. Distributed only by permission. *)
|
|
(* *)
|
|
(***********************************************************************)
|
|
|
|
(* $Id$ *)
|
|
|
|
(* Module [Format]: pretty printing *)
|
|
|
|
(* This module implements a pretty-printing facility to format text
|
|
within ``pretty-printing boxes''. The pretty-printer breaks lines
|
|
at specified break hints, and indents lines according to the box
|
|
structure. *)
|
|
|
|
(* You may consider this module as providing an extension to the
|
|
[printf] facility to provide automatic line breaking. The addition of
|
|
pretty-printing annotations to your regular [printf] formats gives you
|
|
fancy indentation and line breaks.
|
|
Pretty-printing annotations are described below in the documentation of
|
|
the function [fprintf].
|
|
|
|
You may also use the explicit box management and printing functions
|
|
provided by this module. This style is more basic but more verbose
|
|
than the [fprintf] concise formats.
|
|
|
|
For instance, the sequence
|
|
[open_box (); print_string "x ="; print_space (); print_int 1; close_box ()]
|
|
that prints [x = 1] within a pretty-printing box, can be
|
|
abbreviated as [printf "@\[%s@ %i@\]" "x =" 1]. *)
|
|
|
|
(* Rule of thumb for casual users of this library:
|
|
- use simple boxes (as obtained by [open_box 0]);
|
|
- use simple break hints (as obtained by [print_cut ()] that outputs a
|
|
simple break hint, or by [print_space ()] that outputs a space
|
|
indicating a break hint);
|
|
- once a box is opened, display its material with basic printing
|
|
functions (e. g. [print_int] and [print_string]);
|
|
- when the material for a box has been printed, call [close_box ()] to
|
|
close the box;
|
|
- at the end of your routine, evaluate [print_newline ()] to close
|
|
all remaining boxes and flush the pretty-printer. *)
|
|
|
|
(* The behaviour of pretty-printing commands is unspecified
|
|
if there is no opened pretty-printing box. Each box opened 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, the system closes all opened boxes and
|
|
flushes all pending text (as with the [print_newline] function)
|
|
after each phrase. Each phrase is therefore executed in the initial
|
|
state of the pretty-printer. *)
|
|
|
|
(*** Boxes *)
|
|
val 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. *)
|
|
val close_box : unit -> unit;;
|
|
(* Close the most recently opened pretty-printing box. *)
|
|
|
|
(*** Formatting functions *)
|
|
val print_string : string -> unit;;
|
|
(* [print_string str] prints [str] in the current box. *)
|
|
val 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]. *)
|
|
val print_int : int -> unit;;
|
|
(* Print an integer in the current box. *)
|
|
val print_float : float -> unit;;
|
|
(* Print a floating point number in the current box. *)
|
|
val print_char : char -> unit;;
|
|
(* Print a character in the current box. *)
|
|
val print_bool : bool -> unit;;
|
|
(* Print an boolean in the current box. *)
|
|
|
|
(*** Break hints *)
|
|
val 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]. *)
|
|
val 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]. *)
|
|
val 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 one 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. *)
|
|
|
|
val print_flush : unit -> unit;;
|
|
(* Flush the pretty printer: all opened boxes are closed,
|
|
and all pending text is displayed. *)
|
|
val print_newline : unit -> unit;;
|
|
(* Equivalent to [print_flush] followed by a new line. *)
|
|
|
|
val force_newline : unit -> unit;;
|
|
(* Force a newline in the current box. Not the normal way of
|
|
pretty-printing, you should prefer break hints. *)
|
|
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. *)
|
|
|
|
(*** Margin *)
|
|
val 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. *)
|
|
val get_margin : unit -> int;;
|
|
(* Return the position of the right margin. *)
|
|
|
|
(*** Maximum indentation limit *)
|
|
val 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. *)
|
|
val get_max_indent : unit -> int;;
|
|
(* Return the value of the maximum indentation limit (in
|
|
characters). *)
|
|
|
|
(*** Formatting depth: maximum number of boxes allowed before ellipsis *)
|
|
val 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. *)
|
|
val get_max_boxes : unit -> int;;
|
|
(* Return the maximum number of boxes allowed before ellipsis. *)
|
|
val over_max_boxes : unit -> bool;;
|
|
(* Test the maximum number of boxes allowed have
|
|
already been opened. *)
|
|
|
|
(*** Advanced formatting *)
|
|
val 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). *)
|
|
val 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. *)
|
|
val 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. *)
|
|
val 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. *)
|
|
|
|
(*** Tabulations *)
|
|
val open_tbox : unit -> unit;;
|
|
(* Open a tabulation box. *)
|
|
val close_tbox : unit -> unit;;
|
|
(* Close the most recently opened tabulation box. *)
|
|
val 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. *)
|
|
val set_tab : unit -> unit;;
|
|
(* Set a tabulation mark at the current insertion point. *)
|
|
val print_tab : unit -> unit;;
|
|
(* [print_tab ()] is equivalent to [print_tbreak (0,0)]. *)
|
|
|
|
(*** Ellipsis *)
|
|
val set_ellipsis_text : string -> unit;;
|
|
(* Set the text of the ellipsis printed when too many boxes
|
|
are opened (a single dot, [.], by default). *)
|
|
val get_ellipsis_text : unit -> string;;
|
|
(* Return the text of the ellipsis. *)
|
|
|
|
(*** Redirecting formatter output *)
|
|
val set_formatter_out_channel : out_channel -> unit;;
|
|
(* Redirect the pretty-printer output to the given channel. *)
|
|
|
|
val set_formatter_output_functions :
|
|
(string -> int -> int -> unit) -> (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]. *)
|
|
val get_formatter_output_functions :
|
|
unit -> (string -> int -> int -> unit) * (unit -> unit);;
|
|
(* Return the current output functions of the pretty-printer. *)
|
|
|
|
(*** Changing the meaning of indentation and line breaking *)
|
|
val set_all_formatter_output_functions :
|
|
(string -> int -> int -> unit) -> (unit -> unit) ->
|
|
(unit -> unit) -> (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]. *)
|
|
val get_all_formatter_output_functions : unit ->
|
|
(string -> int -> int -> unit) * (unit -> unit) *
|
|
(unit -> unit) * (int -> unit);;
|
|
(* Return the current output functions of the pretty-printer,
|
|
including line breaking and indentation functions. *)
|
|
|
|
(*** Multiple formatted output *)
|
|
type 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). *)
|
|
|
|
val formatter_of_out_channel : out_channel -> formatter;;
|
|
(* [formatter_of_out_channel oc] returns a new formatter that
|
|
writes to the corresponding channel [oc]. *)
|
|
|
|
val std_formatter : formatter;;
|
|
(* The standard formatter used by the formatting functions
|
|
above. It is defined as [formatter_of_out_channel stdout]. *)
|
|
|
|
val 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]. *)
|
|
|
|
val 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]. *)
|
|
|
|
val stdbuf : Buffer.t;;
|
|
(* The string buffer in which [str_formatter] writes. *)
|
|
|
|
val str_formatter : formatter;;
|
|
(* A formatter to use with formatting functions below for
|
|
output to the [stdbuf] string buffer. *)
|
|
|
|
val 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]. *)
|
|
|
|
val make_formatter :
|
|
(string -> int -> int -> unit) -> (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)]. *)
|
|
|
|
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_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_open_tbox : formatter -> unit -> unit;;
|
|
val pp_close_tbox : formatter -> unit -> unit;;
|
|
val pp_print_tbreak : formatter -> int -> int -> unit;;
|
|
val pp_set_tab : formatter -> unit -> unit;;
|
|
val pp_print_tab : formatter -> unit -> unit;;
|
|
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 -> 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_all_formatter_output_functions : formatter ->
|
|
(string -> int -> int -> unit) -> (unit -> unit) ->
|
|
(unit -> unit) -> (int -> unit) -> unit;;
|
|
val pp_get_all_formatter_output_functions : formatter -> unit ->
|
|
(string -> int -> 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]. *)
|
|
|
|
val 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:
|
|
- [@\[]: open a pretty-printing box. The type and offset of the
|
|
box may be optionally specified with the following syntax:
|
|
the [<] character, followed by an optional box type indication,
|
|
then an optional integer offset, and the closing [>] character.
|
|
Box type is one of [h], [v], [hv], [b], or [hov],
|
|
which stand respectively for an horizontal box, a vertical box,
|
|
an ``horizontal-vertical'' box, or an ``horizontal or
|
|
vertical'' box ([b] standing for an ``horizontal or
|
|
vertical'' box demonstrating indentation and [hov] standing
|
|
for a regular``horizontal or vertical'' box).
|
|
For instance, [@\[<hov 2>] opens an ``horizontal or vertical''
|
|
box with indentation 2.
|
|
- [@\]]: close the most recently opened pretty-printing box.
|
|
- [@,]: output a good break as with [print_cut ()].
|
|
- [@ ]: output a space, as with [print_space ()].
|
|
- [@\n]: force a newline, as with [force_newline ()].
|
|
- [@;]: output a good break as with [print_break]. The
|
|
[nspaces] and [offset] parameters of the break may be
|
|
optionally specified with the following syntax:
|
|
the [<] character, followed by an integer [nspaces] value,
|
|
then an integer offset, and a closing [>] character.
|
|
- [@?]: flush the pretty printer as with [print_flush ()].
|
|
- [@.]: flush the pretty printer and output a new line, as with
|
|
[print_newline ()].
|
|
- [@<n>]: print the following item as if it were of length [n].
|
|
Hence, [printf "@<0>%s" arg] is equivalent to [print_as 0 arg].
|
|
If [@<n>] is not followed by a conversion specification,
|
|
then the following character of the format is printed as if
|
|
it were of length [n].
|
|
- [@@]: print a plain [@] character.
|
|
|
|
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. *)
|
|
|
|
val bprintf: Buffer.t -> ('a, formatter, unit) format -> 'a;;
|
|
(* Same as [fprintf], but instead of printing on a formatter,
|
|
writes into the buffer argument. *)
|
|
val printf : ('a, formatter, unit) format -> 'a;;
|
|
(* Same as [fprintf], but output on [std_formatter]. *)
|
|
val eprintf: ('a, formatter, unit) format -> 'a;;
|
|
(* Same as [fprintf], but output on [err_formatter]. *)
|
|
val sprintf: ('a, unit, string) format -> 'a;;
|
|
(* Same as [printf], but instead of printing on a formatter,
|
|
return a string containing the result of formatting
|
|
the arguments. *)
|
|
|
|
|
|
|