1/*  Part of Ciao Prolog compatibility library
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@uva.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (C): 2010, University of Amsterdam
    7
    8    This program is free software; you can redistribute it and/or
    9    modify it under the terms of the GNU General Public License
   10    as published by the Free Software Foundation; either version 2
   11    of the License, or (at your option) any later version.
   12
   13    This program is distributed in the hope that it will be useful,
   14    but WITHOUT ANY WARRANTY; without even the implied warranty of
   15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   16    GNU General Public License for more details.
   17
   18    You should have received a copy of the GNU General Public
   19    License along with this library; if not, write to the Free Software
   20    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   21
   22    As a special exception, if you link this library with other files,
   23    compiled with a Free Software compiler, to produce an executable, this
   24    library does not by itself cause the resulting executable to be covered
   25    by the GNU General Public License. This exception does not however
   26    invalidate any other reasons why the executable file might be covered by
   27    the GNU General Public License.
   28*/
   29
   30:- module(strings,
   31	  [ get_line/2,			% +Stream, -Line
   32	    get_line/1,			% -Line
   33	    write_string/2,		% +Stream, +String
   34	    write_string/1,		% +String
   35	    whitespace//0,
   36	    whitespace0//0,
   37	    string//1			% ?String
   38	  ]).   39:- use_module('../../readutil').

 get_line(+Stream, -Line) is det

Reads from Stream a line of text and unifies Line with it. The end of the line can have UNIX [10] or MS-DOS [13 10] termination, which is not included in Line. At EOF, the term end_of_file is returned.

   53get_line(Stream, Line) :-
   54	read_line_to_codes(Stream, Line).

 get_line(-Line) is det

Behaves like current_input(S), get_line(S,Line).

   60get_line(Line) :-
   61	read_line_to_codes(current_input, Line).

 write_string(+Stream, +String) is det

Writes String onto Stream. Output is not flushed. Is this compatible?

   68write_string(Stream, String) :-
   69	format(Stream, '~s', [String]).

 write_string(+String) is det

Behaves like current_input(S), write_string(S, String).

   75write_string(String) :-
   76	format('~s', [String]).

 whitespace//

In a grammar rule, as whitespace/0, represents whitespace (a positive number of space (32), tab (9), newline (10) or return (13) characters). Thus, Rest is a proper suffix of String with one or more whitespace characters removed. An example of use would be:

attrs([]) --> ""
attrs([N|Ns]) -->
    whitespace,
    attr(N),
    attrs(Ns).

   94whitespace -->
   95	[C],
   96	{ whitespace(C) },
   97	whitespace0.

 whitespace0//

In a grammar rule, as whitespace0/0, represents possible whitespace (any number of space (32), tab (9), newline (10) or return (13) characters). Thus, Rest is String or a proper suffix of String with one or more whitespace characters removed. An example of use would be:

assignment(N,V) -->
   variable_name(N), whitespace0, "=", whitespace0, value(V).

  112whitespace0 -->
  113	[C],
  114	{ whitespace(C) }, !,
  115	whitespace.
  116whitespace0 -->
  117	[].
  118
  119whitespace(9).
  120whitespace(10).
  121whitespace(13).
  122whitespace(32).

 string(?String)//

In a grammar rule, as string/1, represents literally String. An example of use would be:

double(A) -->
    string(A),
    string(A).

  135string([]) -->
  136	[].
  137string([H|T]) -->
  138	[H],
  139	string(T)