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   1  <?php
   2  /**
   3   * Lexer adapted from Simple Test: http://sourceforge.net/projects/simpletest/
   4   * For an intro to the Lexer see:
   5   * https://web.archive.org/web/20120125041816/http://www.phppatterns.com/docs/develop/simple_test_lexer_notes
   6   *
   7   * @author Marcus Baker http://www.lastcraft.com
   8   */
   9  
  10  namespace dokuwiki\Parsing\Lexer;
  11  
  12  /**
  13   * States for a stack machine.
  14   */
  15  class StateStack
  16  {
  17      protected $stack;
  18  
  19      /**
  20       * Constructor. Starts in named state.
  21       * @param string $start        Starting state name.
  22       */
  23      public function __construct($start)
  24      {
  25          $this->stack = array($start);
  26      }
  27  
  28      /**
  29       * Accessor for current state.
  30       * @return string       State.
  31       */
  32      public function getCurrent()
  33      {
  34          return $this->stack[count($this->stack) - 1];
  35      }
  36  
  37      /**
  38       * Adds a state to the stack and sets it to be the current state.
  39       *
  40       * @param string $state        New state.
  41       */
  42      public function enter($state)
  43      {
  44          array_push($this->stack, $state);
  45      }
  46  
  47      /**
  48       * Leaves the current state and reverts
  49       * to the previous one.
  50       * @return boolean    false if we attempt to drop off the bottom of the list.
  51       */
  52      public function leave()
  53      {
  54          if (count($this->stack) == 1) {
  55              return false;
  56          }
  57          array_pop($this->stack);
  58          return true;
  59      }
  60  }