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// Copyright (c) 2020 Dr. Colin Hirsch and Daniel Frey
// Please see LICENSE for license or visit https://github.com/taocpp/PEGTL/
#ifndef TAO_JSON_PEGTL_CONTRIB_CONTROL_ACTION_HPP
#define TAO_JSON_PEGTL_CONTRIB_CONTROL_ACTION_HPP
#include <utility>
#include "../config.hpp"
#include "../match.hpp"
#include "../nothing.hpp"
namespace TAO_JSON_PEGTL_NAMESPACE
{
namespace internal
{
template< typename, typename Rule, template< typename... > class Action, typename ParseInput, typename... States >
inline constexpr bool action_has_unwind = false;
template< typename Rule, template< typename... > class Action, typename ParseInput, typename... States >
inline constexpr bool action_has_unwind< decltype( (void)Action< Rule >::unwind( std::declval< const ParseInput& >(), std::declval< States&& >()... ) ), Rule, Action, ParseInput, States... > = true;
} // namespace internal
struct control_action
: maybe_nothing
{
template< typename Rule,
apply_mode A,
rewind_mode M,
template< typename... >
class Action,
template< typename... >
class Control,
typename ParseInput,
typename... States >
[[nodiscard]] static bool match( ParseInput& in, States&&... st )
{
if constexpr( internal::action_has_unwind< void, Rule, Action, ParseInput, States... > ) {
try {
return control_action::match_impl< Rule, A, M, Action, Control >( in, st... );
}
catch( ... ) {
Action< Rule >::unwind( const_cast< const ParseInput& >( in ), st... );
throw;
}
}
else {
return control_action::match_impl< Rule, A, M, Action, Control >( in, st... );
}
}
private:
template< typename Rule,
apply_mode A,
rewind_mode M,
template< typename... >
class Action,
template< typename... >
class Control,
typename ParseInput,
typename... States >
[[nodiscard]] static bool match_impl( ParseInput& in, States&&... st )
{
Action< Rule >::start( const_cast< const ParseInput& >( in ), st... );
if( TAO_JSON_PEGTL_NAMESPACE::match< Rule, A, M, Action, Control >( in, st... ) ) {
Action< Rule >::success( const_cast< const ParseInput& >( in ), st... );
return true;
}
Action< Rule >::failure( const_cast< const ParseInput& >( in ), st... );
return false;
}
};
} // namespace TAO_JSON_PEGTL_NAMESPACE
#endif
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