1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  1985-2012, University of Amsterdam
    7                              VU University Amsterdam
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(ctypes,
   37          [ is_alnum/1,
   38            is_alpha/1,
   39            is_ascii/1,
   40            is_cntrl/1,
   41            is_csym/1,
   42            is_csymf/1,
   43            is_digit/1,
   44            is_digit/3,
   45            is_endfile/1,
   46            is_endline/1,
   47            is_graph/1,
   48            is_lower/1,
   49            is_newline/1,
   50            is_newpage/1,
   51            is_paren/2,
   52            is_period/1,
   53            is_print/1,
   54            is_punct/1,
   55            is_quote/1,
   56            is_space/1,
   57            is_upper/1,
   58            is_white/1,
   59            to_lower/2,
   60            to_upper/2,
   61            upper_lower/2
   62          ]).   63
   64/** <module> Character code classification
   65
   66This file implements the functionality of the corresponding Quintus
   67library based on SWI-Prolog's code_type/2 predicate. Please check the
   68documentation of this predicate to find the definitions of the classes.
   69
   70@see    code_type/2
   71@see    char_type/2
   72*/
   73
   74is_alnum(C)   :- code_type(C, alnum).
   75is_alpha(C)   :- code_type(C, alpha).
   76is_ascii(C)   :- code_type(C, ascii).
   77is_cntrl(C)   :- code_type(C, cntrl).
   78is_csym(C)    :- code_type(C, csym).
   79is_csymf(C)   :- code_type(C, csymf).
   80is_digit(C)   :- code_type(C, digit).
   81is_graph(C)   :- code_type(C, graph).
   82is_lower(C)   :- code_type(C, lower).
   83is_upper(C)   :- code_type(C, upper).
   84is_period(C)  :- code_type(C, period).
   85is_endline(C) :- code_type(C, end_of_line).
   86is_print(C)   :- is_graph(C).
   87is_punct(C)   :- code_type(C, punct).
   88is_quote(C)   :- code_type(C, quote).
   89is_space(C)   :- code_type(C, space).
   90is_white(C)   :- code_type(C, white).
   91
   92is_endfile(-1).
   93is_newpage(12).                         % Control-L
   94is_newline(10).
   95
   96%!  is_paren(?Open, ?Close) is semidet.
   97%
   98%   True if Open is the open-parenthesis of Close.
   99
  100is_paren(0'(, 0')).                     % Prolog is too good at this
  101is_paren(0'[, 0']).
  102is_paren(0'{, 0'}).
  103
  104%!  to_lower(+U, -L) is det.
  105%
  106%   Downcase a character code. If U  is   the  character  code of an
  107%   uppercase character, unify L with  the   character  code  of the
  108%   lowercase version. Else unify L with U.
  109
  110to_lower(U, L) :-
  111    code_type(L, to_lower(U)).
  112
  113%!  to_upper(+L, -U) is det.
  114%
  115%   Upcase a character code.  If  L  is   the  character  code  of a
  116%   lowercase character, unify L with  the   character  code  of the
  117%   uppercase version. Else unify U with L.
  118
  119to_upper(L, U) :-
  120    code_type(U, to_upper(L)).
  121
  122%!  upper_lower(?U, ?L) is det.
  123%
  124%   True when U is the character code  of an uppercase character and
  125%   L  is  the  character  code    of  the  corresponding  lowercase
  126%   character.
  127
  128upper_lower(Upper, Lower) :-
  129    nonvar(Upper),
  130    !,
  131    code_type(Lower, lower(Upper)).
  132upper_lower(Upper, Lower) :-
  133    code_type(Upper, upper(Lower)).
  134
  135
  136%!  is_digit(+C, +Base, -Weight) is det.
  137%!  is_digit(-C, +Base, +Weight) is det.
  138%
  139%   Succeeds if `C' is a digit using `Base'  as  base  and  `Weight'
  140%   represents its value.  Only the base-10 case is handled by code_type.
  141
  142is_digit(C, Base, Weight) :-
  143    Base == 10,
  144    !,
  145    code_type(C, digit(Weight)).
  146is_digit(C, Base, Weight) :-
  147    between(2, 36, Base),
  148    succ(X, Base),
  149    between(0, X, Weight),
  150    is_digit(C, Weight).
  151
  152is_digit(C, Weight) :-
  153    Weight < 10,
  154    !,
  155    plus(Weight, 0'0, C).
  156is_digit(C, Weight) :-
  157    plus(Weight, 87, C),
  158    !.         /* `a`-10 */
  159is_digit(C, Weight) :-
  160    plus(Weight, 55, C).            /* `A`-10 */