Deterministic Finite Automation

gistfile1.js

var automaton = {
    current: {
      state: 0
    }

  , defaults: {
      state: 0
    }

  , transition: [
        { "p": 1 }
      , { "u": 2, "r": 6 }
      , { "b": 3 }
      , { "l": 4 }
      , { "i": 5 }
      , { "c": 11 }
      , { "i": 7 }
      , { "v": 8 }
      , { "a": 9 }
      , { "t": 10 }
      , { "e": 11 }
      , { " ": -1 }
    ]

  , reset: function(){
      for( var key in this.current )
        this.current[ key ] = this.defaults[ key ];
    }

  , entry: function( inputStr ){
      this.reset();

      for( i = 0; inputStr.length > i; i++ ){
        var res = this.accept( inputStr[ i ] );

        if( res === 0 )
          continue;
        else if( res === 1 || inputStr.length - 1 > i )
          return false;
        else if( res === -1 )
          return true;
      }
      
      return false;
    }

  , accept: function( inputChar ){
      var next = this.transition[ this.current.state ][ inputChar ];

      if( next !== undefined ){
        if( next === -1 )
          return -1;

        this.current.state = next;
        return 0;
      }

      return 1;
    }
};


automaton.entry( 'public ' );  // true
automaton.entry( 'private ' ); // true