/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 2011-2013, University of Amsterdam
VU University Amsterdam
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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*/
:- module(writef,
[ writef/1, % +Format
writef/2, % +Format, +Args
swritef/2, % -String, +Format
swritef/3 % -String, +Format, +Args
]).
:- set_prolog_flag(generate_debug_info, false).
/** <module> Old-style formatted write
This library provides writef/1 and friends. These predicates originate
from Edinburgh C-Prolog and and provided for compatibility purposes. New
code should use format/1, format/2 and friends, which are currently
supported by more Prolog implementations.
The writef-family of predicates conflicts with the modern
_|character-esacapes|_ flag about the interpretation of \-sequences.
This can be avoided by
1. Disable character escapes (not recommended unless one wants to
run really outdated code unmodified).
2. Double the \ for conflicting interpretations
3. Use ISO compliant alternatives for conflicting interpretations
@copyright Copied from Edinburgh C-Prolog. Original version by Byrd,
changed many times since.
*/
%! writef(+Format) is det.
%! writef(+Format, +Arguments) is det.
%
% Formatted write to the =current_output=. Format is a format
% specifier. Some escape sequences require arguments that must be
% provided in the list Arguments. There are two types of escape
% sequences: special characters start with =|\|= and include
% arguments start with =|%|=. The special character sequences are:
%
% | =|\n|= | Output a newline character |
% | =|\l|= | Output a line separator (same as =|\n|=) |
% | =|\r|= | Output a carriage-return character (ASCII 13) |
% | =|\r|= | Output a TAB character (ASCII 9) |
% | =|\\|= | Output =|\|= |
% | =|\%|= | Output =|%|= |
% | =|\nnn|= | Output character <nnn>. <nnn> is a 1-3 decimal number |
%
% Escape sequences to include arguments from Arguments. Each time
% a %-escape sequence is found in Format the next argument from
% Arguments is formatted according to the specification.
%
% | =|%t|= | print/1 the next item (mnemonic: term) |
% | =|%w|= | write/1 the next item |
% | =|%q|= | writeq/1 the next item |
% | =|%d|= | display/1 the next item |
% | =|%n|= | Put the next item as a character |
% | =|%r|= | Write the next item N times where N is the second item (an integer) |
% | =|%s|= | Write the next item as a String (so it must be a list of characters) |
% | =|%f|= |Perform a ttyflush/0 (no items used) |
% | =|%Nc|= | Write the next item Centered in N columns. |
% | =|%Nl|= | Write the next item Left justified in N columns. |
% | =|%Nr|= | Write the next item Right justified in N columns. |
%
% @deprecated New code should use format/1, format/2, etc.
writef(Format) :-
writef(Format, []).
writef([F|String], List) :-
'$writefs'([F|String], List),
fail. % clean up global stack
writef(String, List) :-
string(String),
string_codes(String, Fstring),
'$writefs'(Fstring, List),
fail. % clean up global stack
writef(Format, List) :-
atom(Format),
name(Format, Fstring),
'$writefs'(Fstring, List),
fail. % clean up global stack
writef(_, _).
%! swritef(-String, +Format) is det.
%! swritef(-String, +Format, +Arguments) is det.
%
% Use writef/1 or writef/2 and write the result to a _string_.
% Note that this is a string in the sense of string_codes/2,
% _not_ a list of character(-code)s.
%
% @deprecated. See format/2,3 and/or with_output_to/2.
swritef(String, Format, Arguments) :-
with_output_to(string(String), writef(Format, Arguments)).
swritef(String, Format) :-
with_output_to(string(String), writef(Format)).
% Formatted write for a string (i.e. a list of
% character codes).
'$writefs'([], _).
'$writefs'([0'%, A|Rest], List) :- % %<$action'>
'$action'(A, List, More),
!,
'$writefs'(Rest, More).
'$writefs'([0'%, D|Rest], [Head|Tail]) :- % %<columns><just>
between(0'0, 0'9, D),
'$getpad'(Size, Just, [D|Rest], More),
!,
'$padout'(Head, Size, Just),
'$writefs'(More, Tail).
'$writefs'([0'\\, C|Rest], List) :- % \<special>
'$special'(C, Char),
!,
put(Char),
'$writefs'(Rest, List).
'$writefs'([0'\\|Rest], List) :- % \<character code in decimal>
'$getcode'(Char, Rest, More),
!,
put(Char),
'$writefs'(More, List).
'$writefs'([Char|Rest], List) :- % <ordinary character>
put(Char),
'$writefs'(Rest, List).
'$action'(0't, [Head|Tail], Tail) :- % Term
print(Head).
'$action'(0'd, [Head|Tail], Tail) :- % Display
write_canonical(Head).
'$action'(0'w, [Head|Tail], Tail) :- % Write
write(Head).
'$action'(0'q, [Head|Tail], Tail) :- % Quoted
writeq(Head).
'$action'(0'p, [Head|Tail], Tail) :- % Print
print(Head).
'$action'(0'f, List, List) :- % Flush
ttyflush.
'$action'(0'n, [Char|Tail], Tail) :- % iNteger (character)
put(Char).
'$action'(0'r, [Thing, Times|Tail], Tail) :- % Repeatedly
'$writelots'(Times, Thing).
'$action'(0's, [Head|Tail], Tail) :- % String
'$padout'(Head).
'$special'(0'n, 10). /* n */
'$special'(0'l, 10). /* l */
'$special'(0'r, 10). /* r */
'$special'(0't, 9). /* t */
'$special'(0'\\, 0'\\). /* \ */
'$special'(0'%, 0'%). /* % */
'$getcode'(Char, In, Out) :-
'$getdigits'(3, Digits, In, Out),
Digits = [_|_],
name(Char, Digits),
Char < 128.
'$getdigits'(Limit, [Digit|Digits], [Digit|Out0], Out) :-
Limit > 0,
between(0'0, 0'9, Digit),
Fewer is Limit - 1,
!,
'$getdigits'(Fewer, Digits, Out0, Out).
'$getdigits'(_, [], Out, Out).
'$writelots'(N, T) :-
N > 0,
!,
write(T),
M is N - 1,
'$writelots'(M, T).
'$writelots'(_, _).
/* The new formats are %nC, %nL, and %nR for centered, left, and right
justified output of atoms, integers, and strings. This is meant to
simplify the production of tabular output when it is appropriate.
At least one space will always precede/follow the item written.
*/
'$getpad'(Size, Just, In, Out) :-
'$getdigits'(3, Digits, In, [Out1|Out]),
name(Size, Digits),
'$getpad'(Out1, Just).
'$getpad'(0'r, r). % right justified
'$getpad'(0'l, l). % left justified
'$getpad'(0'c, c). % centered
'$getpad'(0'R, r). % right justified
'$getpad'(0'L, l). % left justified
'$getpad'(0'C, c). % centered
% '$padout'(A, S, J) writes the item A in a
% field of S or more characters, Justified.
'$padout'(String, Size, Just) :-
'$string'(String),
!,
name(Atom, String),
'$padout'(Atom, Size, Just).
'$padout'(Term, Size, Just) :-
format(string(Atom), Term, Atom),
atom_length(Atom, Length),
'$padout'(Just, Size, Length, Left, Right),
tab(Left),
write(Atom),
tab(Right).
'$string'(0) :- !, fail.
'$string'([]) :- !.
'$string'([H|T]) :-
'$print'(H),
!,
'$string'(T).
'$print'(10). % newline
'$print'(9). % tab
'$print'(X) :-
integer(X),
between(32, 0'~, X).
% '$padout'(Just, Size, Length, Left, Right)
% calculates the number of spaces to put
% on the Left and Right of an item needing
% Length characters in a field of Size.
'$padout'(l, Size, Length, 0, Right) :-
!,
Right is max(1, Size-Length).
'$padout'(r, Size, Length, Left, 0) :-
!,
Left is max(1, Size-Length).
'$padout'(c, Size, Length, Left, Right) :-
Left is max(1, round((Size - Length)/2)),
Right is max(1, Size - Length - Left).
% '$padout'(Str) writes a string.
'$padout'([Head|Tail]) :-
!,
put(Head),
'$padout'(Tail).
'$padout'([]).