text: #ifndef __tree_ValueScope_h__
  #define __tree_ValueScope_h__
  
  #include <list>
  #include <map>
  #include <string>
  #include "less/TokenList.h"
  
  class ValueScope {
  public:
    virtual const TokenList* getVariable(const std::string& key) const = 0;
  };
  
  #endif  // __tree_ValueScope_h__
  