kc3-lang/kc3/libc3/facts_spec_cursor.c

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• Hash : fadc8073
  Author : Thomas de Grivel
  Date : 2023-01-25T10:24:29
  

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• libc3/facts_spec_cursor.c

• /* c3
   * Copyright 2022,2023 kmx.io <contact@kmx.io>
   *
   * Permission is hereby granted to use this software excepted
   * on Apple computers granted the above copyright notice and
   * this permission paragraph are included in all copies and
   * substantial portions of this software.
   *
   * THIS SOFTWARE IS PROVIDED "AS-IS" WITHOUT ANY GUARANTEE OF
   * PURPOSE AND PERFORMANCE. IN NO EVENT WHATSOEVER SHALL THE
   * AUTHOR BE CONSIDERED LIABLE FOR THE USE AND PERFORMANCE OF
   * THIS SOFTWARE.
   */
  #include <assert.h>
  #include <err.h>
  #include "facts_spec_cursor.h"
  
  s_facts_spec_cursor *
  facts_spec_cursor_init (s_facts_spec_cursor *cursor,
                          p_facts_spec spec)
  {
    assert(cursor);
    assert(spec);
    cursor->spec = spec;
    cursor->subject = spec[0];
    cursor->pos = 1;
    return cursor;
  }
  
  bool facts_spec_cursor_next (s_facts_spec_cursor *cursor,
                               s_fact *fact)
  {
    const s_tag *predicate;
    const s_tag *object;
    assert(cursor);
    assert(fact);
    do {
      if (!cursor->subject)
        return false;
      predicate = cursor->spec[cursor->pos];
      if (! predicate) {
        cursor->subject = cursor->spec[cursor->pos + 1];
        cursor->pos += 2;
      }
    } while (! predicate);
    object = cursor->spec[cursor->pos + 1];
    if (! object) {
      warnx("facts_spec_cursor_next: NULL object");
      return false;
    }
    cursor->pos += 2;
    fact->subject = cursor->subject;
    fact->predicate = predicate;
    fact->object = object;
    return true;
  }
  

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