71 lines
2.3 KiB
C++
71 lines
2.3 KiB
C++
// Copyright (c) 2019-2021 Dr. Colin Hirsch and Daniel Frey
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
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#ifndef TAO_PEGTL_CHANGE_STATE_HPP
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#define TAO_PEGTL_CHANGE_STATE_HPP
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#include <type_traits>
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#include "apply_mode.hpp"
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#include "config.hpp"
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#include "match.hpp"
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#include "nothing.hpp"
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#include "rewind_mode.hpp"
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#include "internal/dependent_false.hpp"
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namespace TAO_PEGTL_NAMESPACE
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{
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template< typename NewState >
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struct change_state
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: maybe_nothing
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{
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template< typename Rule,
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apply_mode A,
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rewind_mode M,
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template< typename... >
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class Action,
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template< typename... >
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class Control,
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typename ParseInput,
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typename... States >
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[[nodiscard]] static bool match( ParseInput& in, States&&... st )
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{
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if constexpr( std::is_constructible_v< NewState, const ParseInput&, States... > ) {
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NewState s( static_cast< const ParseInput& >( in ), st... );
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if( TAO_PEGTL_NAMESPACE::match< Rule, A, M, Action, Control >( in, s ) ) {
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if constexpr( A == apply_mode::action ) {
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Action< Rule >::success( static_cast< const ParseInput& >( in ), s, st... );
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}
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return true;
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}
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return false;
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}
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else if constexpr( std::is_default_constructible_v< NewState > ) {
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NewState s;
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if( TAO_PEGTL_NAMESPACE::match< Rule, A, M, Action, Control >( in, s ) ) {
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if constexpr( A == apply_mode::action ) {
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Action< Rule >::success( static_cast< const ParseInput& >( in ), s, st... );
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}
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return true;
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}
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return false;
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}
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else {
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static_assert( internal::dependent_false< NewState >, "unable to instantiate new state" );
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}
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}
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template< typename ParseInput,
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typename... States >
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static void success( const ParseInput& in, NewState& s, States&&... st ) noexcept( noexcept( s.success( in, st... ) ) )
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{
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s.success( in, st... );
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}
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};
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} // namespace TAO_PEGTL_NAMESPACE
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#endif
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