text: 
  //              Copyright Catch2 Authors
  // Distributed under the Boost Software License, Version 1.0.
  //   (See accompanying file LICENSE_1_0.txt or copy at
  //        https://www.boost.org/LICENSE_1_0.txt)
  
  // SPDX-License-Identifier: BSL-1.0
  #ifndef CATCH_LAZY_EXPR_HPP_INCLUDED
  #define CATCH_LAZY_EXPR_HPP_INCLUDED
  
  #include <iosfwd>
  
  namespace Catch {
  
      class ITransientExpression;
  
      class LazyExpression {
          friend class AssertionHandler;
          friend struct AssertionStats;
          friend class RunContext;
  
          ITransientExpression const* m_transientExpression = nullptr;
          bool m_isNegated;
      public:
          LazyExpression( bool isNegated ):
              m_isNegated(isNegated)
          {}
          LazyExpression(LazyExpression const& other) = default;
          LazyExpression& operator = ( LazyExpression const& ) = delete;
  
          explicit operator bool() const {
              return m_transientExpression != nullptr;
          }
  
          friend auto operator << ( std::ostream& os, LazyExpression const& lazyExpr ) -> std::ostream&;
      };
  
  } // namespace Catch
  
  #endif // CATCH_LAZY_EXPR_HPP_INCLUDED
  