168 lines
7.6 KiB
OCaml
168 lines
7.6 KiB
OCaml
(***********************************************************************)
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(* *)
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(* OCaml *)
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(* *)
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(* Xavier Leroy and Pierre Weis, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the GNU Library General Public License, with *)
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(* the special exception on linking described in file ../LICENSE. *)
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(* *)
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(***********************************************************************)
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(** Formatted output functions. *)
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val fprintf : out_channel -> ('a, out_channel, unit) format -> 'a
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(** [fprintf outchan format arg1 ... argN] formats the arguments
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[arg1] to [argN] according to the format string [format], and
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outputs the resulting string on the channel [outchan].
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The format string is a character string which contains two types of
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objects: plain characters, which are simply copied to the output
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channel, and conversion specifications, each of which causes
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conversion and printing of arguments.
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Conversion specifications have the following form:
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[% [flags] [width] [.precision] type]
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In short, a conversion specification consists in the [%] character,
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followed by optional modifiers and a type which is made of one or
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two characters.
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The types and their meanings are:
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- [d], [i]: convert an integer argument to signed decimal.
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- [u], [n], [l], [L], or [N]: convert an integer argument to
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unsigned decimal. Warning: [n], [l], [L], and [N] are
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used for [scanf], and should not be used for [printf].
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- [x]: convert an integer argument to unsigned hexadecimal,
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using lowercase letters.
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- [X]: convert an integer argument to unsigned hexadecimal,
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using uppercase letters.
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- [o]: convert an integer argument to unsigned octal.
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- [s]: insert a string argument.
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- [S]: convert a string argument to OCaml syntax (double quotes, escapes).
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- [c]: insert a character argument.
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- [C]: convert a character argument to OCaml syntax
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(single quotes, escapes).
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- [f]: convert a floating-point argument to decimal notation,
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in the style [dddd.ddd].
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- [F]: convert a floating-point argument to OCaml syntax ([dddd.]
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or [dddd.ddd] or [d.ddd e+-dd]).
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- [e] or [E]: convert a floating-point argument to decimal notation,
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in the style [d.ddd e+-dd] (mantissa and exponent).
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- [g] or [G]: convert a floating-point argument to decimal notation,
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in style [f] or [e], [E] (whichever is more compact).
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- [B]: convert a boolean argument to the string [true] or [false]
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- [b]: convert a boolean argument (deprecated; do not use in new
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programs).
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- [ld], [li], [lu], [lx], [lX], [lo]: convert an [int32] argument to
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the format specified by the second letter (decimal, hexadecimal, etc).
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- [nd], [ni], [nu], [nx], [nX], [no]: convert a [nativeint] argument to
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the format specified by the second letter.
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- [Ld], [Li], [Lu], [Lx], [LX], [Lo]: convert an [int64] argument to
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the format specified by the second letter.
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- [a]: user-defined printer. Take two arguments and apply the
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first one to [outchan] (the current output channel) and to the
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second argument. The first argument must therefore have type
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[out_channel -> 'b -> unit] and the second ['b].
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The output produced by the function is inserted in the output of
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[fprintf] at the current point.
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- [t]: same as [%a], but take only one argument (with type
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[out_channel -> unit]) and apply it to [outchan].
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- [\{ fmt %\}]: convert a format string argument to its type digest.
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The argument must have the same type as the internal format string
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[fmt].
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- [( fmt %)]: format string substitution. Take a format string
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argument and substitute it to the internal format string [fmt]
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to print following arguments. The argument must have the same
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type as the internal format string [fmt].
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- [!]: take no argument and flush the output.
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- [%]: take no argument and output one [%] character.
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- [\@]: take no argument and output one [\@] character.
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- [,]: take no argument and output nothing: a no-op delimiter for
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conversion specifications.
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The optional [flags] are:
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- [-]: left-justify the output (default is right justification).
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- [0]: for numerical conversions, pad with zeroes instead of spaces.
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- [+]: for signed numerical conversions, prefix number with a [+]
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sign if positive.
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- space: for signed numerical conversions, prefix number with a
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space if positive.
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- [#]: request an alternate formatting style for numbers.
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The optional [width] is an integer indicating the minimal
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width of the result. For instance, [%6d] prints an integer,
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prefixing it with spaces to fill at least 6 characters.
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The optional [precision] is a dot [.] followed by an integer
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indicating how many digits follow the decimal point in the [%f],
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[%e], and [%E] conversions. For instance, [%.4f] prints a [float] with
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4 fractional digits.
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The integer in a [width] or [precision] can also be specified as
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[*], in which case an extra integer argument is taken to specify
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the corresponding [width] or [precision]. This integer argument
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precedes immediately the argument to print.
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For instance, [%.*f] prints a [float] with as many fractional
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digits as the value of the argument given before the float. *)
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val printf : ('a, out_channel, unit) format -> 'a
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(** Same as {!Printf.fprintf}, but output on [stdout]. *)
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val eprintf : ('a, out_channel, unit) format -> 'a
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(** Same as {!Printf.fprintf}, but output on [stderr]. *)
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val sprintf : ('a, unit, string) format -> 'a
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(** Same as {!Printf.fprintf}, but instead of printing on an output channel,
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return a string containing the result of formatting the arguments. *)
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val bprintf : Buffer.t -> ('a, Buffer.t, unit) format -> 'a
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(** Same as {!Printf.fprintf}, but instead of printing on an output channel,
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append the formatted arguments to the given extensible buffer
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(see module {!Buffer}). *)
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val ifprintf : 'a -> ('b, 'a, unit) format -> 'b
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(** Same as {!Printf.fprintf}, but does not print anything.
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Useful to ignore some material when conditionally printing.
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@since 3.10.0
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*)
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(** Formatted output functions with continuations. *)
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val kfprintf : (out_channel -> 'a) -> out_channel ->
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('b, out_channel, unit, 'a) format4 -> 'b;;
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(** Same as [fprintf], but instead of returning immediately,
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passes the out channel to its first argument at the end of printing.
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@since 3.09.0
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*)
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val ikfprintf : (out_channel -> 'a) -> out_channel ->
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('b, out_channel, unit, 'a) format4 -> 'b
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;;
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(** Same as [kfprintf] above, but does not print anything.
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Useful to ignore some material when conditionally printing.
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@since 4.0
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*)
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val ksprintf : (string -> 'a) -> ('b, unit, string, 'a) format4 -> 'b;;
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(** Same as [sprintf] above, but instead of returning the string,
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passes it to the first argument.
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@since 3.09.0
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*)
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val kbprintf : (Buffer.t -> 'a) -> Buffer.t ->
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('b, Buffer.t, unit, 'a) format4 -> 'b;;
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(** Same as [bprintf], but instead of returning immediately,
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passes the buffer to its first argument at the end of printing.
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@since 3.10.0
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*)
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(** Deprecated *)
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val kprintf : (string -> 'a) -> ('b, unit, string, 'a) format4 -> 'b
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(** A deprecated synonym for [ksprintf]. *)
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