112 lines
5.5 KiB
OCaml
112 lines
5.5 KiB
OCaml
(***********************************************************************)
|
|
(* *)
|
|
(* Objective Caml *)
|
|
(* *)
|
|
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
|
|
(* *)
|
|
(* Copyright 1996 Institut National de Recherche en Informatique et *)
|
|
(* en Automatique. All rights reserved. This file is distributed *)
|
|
(* under the terms of the GNU Library General Public License. *)
|
|
(* *)
|
|
(***********************************************************************)
|
|
|
|
(* $Id$ *)
|
|
|
|
(** Formatted output functions. *)
|
|
|
|
(** [fprintf outchan format arg1 ... argN] formats the arguments
|
|
[arg1] to [argN] according to the format string [format],
|
|
and outputs the resulting string on the channel [outchan].
|
|
|
|
The format is a character string which contains two types of
|
|
objects: plain characters, which are simply copied to the
|
|
output channel, and conversion specifications, each of which
|
|
causes conversion and printing of one argument.
|
|
|
|
Conversion specifications consist in the [%] character, followed
|
|
by optional flags and field widths, followed by one or two conversion
|
|
character. The conversion characters and their meanings are:
|
|
- [d] or [i]: convert an integer argument to signed decimal
|
|
- [u]: convert an integer argument to unsigned decimal
|
|
- [x]: convert an integer argument to unsigned hexadecimal,
|
|
using lowercase letters.
|
|
- [X]: convert an integer argument to unsigned hexadecimal,
|
|
using uppercase letters.
|
|
- [o]: convert an integer argument to unsigned octal.
|
|
- [s]: insert a string argument
|
|
- [c]: insert a character argument
|
|
- [f]: convert a floating-point argument to decimal notation,
|
|
in the style [dddd.ddd]
|
|
- [e] or [E]: convert a floating-point argument to decimal notation,
|
|
in the style [d.ddd e+-dd] (mantissa and exponent)
|
|
- [g] or [G]: convert a floating-point argument to decimal notation,
|
|
in style [f] or [e], [E] (whichever is more compact)
|
|
- [b]: convert a boolean argument to the string [true] or [false]
|
|
- [ld], [li], [lu], [lx], [lX], [lo]: convert an [int32] argument to
|
|
the format specified by the second letter (decimal, hexadecimal, etc).
|
|
- [nd], [ni], [nu], [nx], [nX], [no]: convert a [nativeint] argument to
|
|
the format specified by the second letter.
|
|
- [Ld], [Li], [Lu], [Lx], [LX], [Lo]: convert an [int64] argument to
|
|
the format specified by the second letter.
|
|
- [a]: user-defined printer. Takes two arguments and apply the first
|
|
one to [outchan] (the current output channel) and to the second
|
|
argument. The first argument must therefore have type
|
|
[out_channel -> 'b -> unit] and the second ['b].
|
|
The output produced by the function is therefore inserted
|
|
in the output of [fprintf] at the current point.
|
|
- [t]: same as [%a], but takes only one argument (with type
|
|
[out_channel -> unit]) and apply it to [outchan].
|
|
- [%]: take no argument and output one [%] character.
|
|
|
|
The optional flags include:
|
|
- [-]: left-justify the output (default is right justification).
|
|
- [+]: for numerical conversions, prefix number with a [+] sign if positive.
|
|
- space: for numerical conversions, prefix number with a space if positive.
|
|
- [#]: request an alternate formatting style for numbers.
|
|
|
|
The field widths are composed of an optional integer literal
|
|
indicating the minimal width of the result, possibly followed by
|
|
a dot [.] and another integer literal indicating how many digits
|
|
follow the decimal point in the [%f], [%e], and [%E] conversions.
|
|
For instance, [%6d] prints an integer, prefixing it with spaces to
|
|
fill at least 6 characters; and [%.4f] prints a float with 4
|
|
fractional digits. Each or both of the integer literals can also be
|
|
specified as a [*], in which case an extra integer argument is taken
|
|
to specify the corresponding width or precision.
|
|
|
|
Warning: if too few arguments are provided,
|
|
for instance because the [printf] function is partially
|
|
applied, the format is immediately printed up to
|
|
the conversion of the first missing argument; printing
|
|
will then resume when the missing arguments are provided.
|
|
For example, [List.iter (printf "x=%d y=%d " 1) [2;3]]
|
|
prints [x=1 y=2 3] instead of the expected
|
|
[x=1 y=2 x=1 y=3]. To get the expected behavior, do
|
|
[List.iter (fun y -> printf "x=%d y=%d " 1 y) [2;3]]. *)
|
|
val fprintf: out_channel -> ('a, out_channel, unit) format -> 'a
|
|
|
|
(** Same as {!Printf.fprintf}, but output on [stdout]. *)
|
|
val printf: ('a, out_channel, unit) format -> 'a
|
|
|
|
(** Same as {!Printf.fprintf}, but output on [stderr]. *)
|
|
val eprintf: ('a, out_channel, unit) format -> 'a
|
|
|
|
(** Same as {!Printf.fprintf}, but instead of printing on an output channel,
|
|
return a string containing the result of formatting
|
|
the arguments. *)
|
|
val sprintf: ('a, unit, string) format -> 'a
|
|
|
|
(** Same as {!Printf.fprintf}, but instead of printing on an output channel,
|
|
append the formatted arguments to the given extensible buffer
|
|
(see module {!Buffer}). *)
|
|
val bprintf: Buffer.t -> ('a, Buffer.t, unit) format -> 'a
|
|
|
|
(*--*)
|
|
|
|
(* For system use only. Don't call directly. *)
|
|
|
|
val scan_format:
|
|
string -> int -> (string -> int -> 'a)
|
|
-> ('b ->'c -> int -> 'a)
|
|
-> ('e -> int -> 'a) -> 'a
|