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   1  <?php
   2  /**
   3   * PHP_ParserGenerator, a php 5 parser generator.
   4   * 
   5   * This is a direct port of the Lemon parser generator, found at
   6   * {@link http://www.hwaci.com/sw/lemon/}
   7   *
   8   * PHP version 5
   9   *
  10   * LICENSE: This source file is subject to version 3.01 of the PHP license
  11   * that is available through the world-wide-web at the following URI:
  12   * http://www.php.net/license/3_01.txt.  If you did not receive a copy of
  13   * the PHP License and are unable to obtain it through the web, please
  14   * send a note to [email protected] so we can mail you a copy immediately.
  15   *
  16   * @category   php
  17   * @package    PHP_ParserGenerator
  18   * @author     Gregory Beaver <[email protected]>
  19   * @copyright  2006 Gregory Beaver
  20   * @license    http://www.php.net/license/3_01.txt  PHP License 3.01
  21   * @version    CVS: $Id$
  22   * @since      File available since Release 0.1.0
  23   */
  24  /**
  25   * Every shift or reduce operation is stored as one of the following objects.
  26   * 
  27   * @package    PHP_ParserGenerator
  28   * @author     Gregory Beaver <[email protected]>
  29   * @copyright  2006 Gregory Beaver
  30   * @license    http://www.php.net/license/3_01.txt  PHP License 3.01
  31   * @version    0.1.0
  32   * @since      Class available since Release 0.1.0
  33   */
  34  class PHP_ParserGenerator_Action {
  35      const SHIFT = 1,
  36      ACCEPT = 2,
  37      REDUCE = 3,
  38      ERROR = 4,
  39      /**
  40             * Was a reduce, but part of a conflict
  41             */
  42      CONFLICT = 5,
  43      /**
  44             * Was a shift.  Precedence resolved conflict
  45             */
  46      SH_RESOLVED = 6,
  47      /**
  48             * Was a reduce.  Precedence resolved conflict
  49             */
  50      RD_RESOLVED = 7,
  51      /**
  52             * Deleted by compression
  53             * @see PHP_ParserGenerator::CompressTables()
  54             */
  55      NOT_USED = 8;
  56      /**
  57       * The look-ahead symbol that triggers this action
  58       * @var PHP_ParserGenerator_Symbol
  59       */
  60      public $sp;       /* The look-ahead symbol */
  61      /**
  62       * This defines the kind of action, and must be one
  63       * of the class constants.
  64       *
  65       * - {@link PHP_ParserGenerator_Action::SHIFT}
  66       * - {@link PHP_ParserGenerator_Action::ACCEPT}
  67       * - {@link PHP_ParserGenerator_Action::REDUCE}
  68       * - {@link PHP_ParserGenerator_Action::ERROR}
  69       * - {@link PHP_ParserGenerator_Action::CONFLICT}
  70       * - {@link PHP_ParserGenerator_Action::SH_RESOLVED}
  71       * - {@link PHP_ParserGenerator_Action:: RD_RESOLVED}
  72       * - {@link PHP_ParserGenerator_Action::NOT_USED}
  73       */
  74      public $type;
  75      /**
  76       * The new state, if this is a shift,
  77       * the parser rule index, if this is a reduce.
  78       *
  79       * @var PHP_ParserGenerator_State|PHP_ParserGenerator_Rule
  80       */
  81      public $x;
  82      /**
  83       * The next action for this state.
  84       * @var PHP_ParserGenerator_Action
  85       */
  86      public $next;
  87  
  88      /**
  89       * Compare two actions
  90       * 
  91       * This is used by {@link Action_sort()} to compare actions
  92       */
  93      static function actioncmp(PHP_ParserGenerator_Action $ap1,
  94                                PHP_ParserGenerator_Action $ap2)
  95      {
  96          $rc = $ap1->sp->index - $ap2->sp->index;
  97          if ($rc === 0) {
  98              $rc = $ap1->type - $ap2->type;
  99          }
 100          if ($rc === 0) {
 101              if ($ap1->type != self::REDUCE &&
 102              $ap1->type != self::RD_RESOLVED &&
 103              $ap1->type != self::CONFLICT) {
 104                  throw new Exception('action has not been processed: ' .
 105                  $ap1->sp->name);
 106              }
 107              if ($ap2->type != self::REDUCE &&
 108              $ap2->type != self::RD_RESOLVED &&
 109              $ap2->type != self::CONFLICT) {
 110                  throw new Exception('action has not been processed: ' .
 111                  $ap2->sp->name);
 112              }
 113              $rc = $ap1->x->index - $ap2->x->index;
 114          }
 115          return $rc;
 116      }
 117  
 118      /**
 119       * create linked list of PHP_ParserGenerator_Actions
 120       *
 121       * @param PHP_ParserGenerator_Action|null
 122       * @param int one of the class constants from PHP_ParserGenerator_Action
 123       * @param PHP_ParserGenerator_Symbol
 124       * @param PHP_ParserGenerator_Symbol|PHP_ParserGenerator_Rule
 125       */
 126      static function Action_add(&$app, $type, PHP_ParserGenerator_Symbol $sp, $arg)
 127      {
 128          $new = new PHP_ParserGenerator_Action;
 129          $new->next = $app;
 130          $app = $new;
 131          $new->type = $type;
 132          $new->sp = $sp;
 133          $new->x = $arg;
 134      }
 135  
 136      /**
 137       * Sort parser actions
 138       * @see PHP_ParserGenerator_Data::FindActions()
 139       */
 140      static function Action_sort(PHP_ParserGenerator_Action $ap)
 141      {
 142          $ap = PHP_ParserGenerator::msort($ap, 'next', array('PHP_ParserGenerator_Action', 'actioncmp'));
 143          return $ap;
 144      }
 145  
 146      /**
 147       * Print an action to the given file descriptor.  Return FALSE if
 148       * nothing was actually printed.
 149       * @see PHP_ParserGenerator_Data::ReportOutput()
 150       */
 151      function PrintAction($fp, $indent)
 152      {
 153          $result = 1;
 154          switch ($this->type)
 155          {
 156              case self::SHIFT:
 157                  fprintf($fp, "%$indent}s shift  %d", $this->sp->name, $this->x->statenum);
 158                  break;
 159              case self::REDUCE:
 160                  fprintf($fp, "%$indent}s reduce %d", $this->sp->name, $this->x->index);
 161                  break;
 162              case self::ACCEPT:
 163                  fprintf($fp, "%$indent}s accept", $this->sp->name);
 164                  break;
 165              case self::ERROR:
 166                  fprintf($fp, "%$indent}s error", $this->sp->name);
 167                  break;
 168              case self::CONFLICT:
 169                  fprintf($fp, "%$indent}s reduce %-3d ** Parsing conflict **", $this->sp->name, $this->x->index);
 170                  break;
 171              case self::SH_RESOLVED:
 172              case self::RD_RESOLVED:
 173              case self::NOT_USED:
 174                  $result = 0;
 175                  break;
 176          }
 177          return $result;
 178      }
 179  }
 180  ?>