72 lines
2.4 KiB
C++
72 lines
2.4 KiB
C++
// Copyright (c) 2020-2021 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_MUST_IF_HPP
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#define TAO_PEGTL_MUST_IF_HPP
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#if !defined( __cpp_exceptions )
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#error "Exception support required for tao/pegtl/internal/must.hpp"
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#else
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#include <type_traits>
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#include "config.hpp"
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#include "internal/has_error_message.hpp"
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#include "normal.hpp"
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namespace TAO_PEGTL_NAMESPACE
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{
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namespace internal
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{
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template< typename Errors, typename Rule, typename = void >
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inline constexpr bool raise_on_failure = ( Errors::template message< Rule > != nullptr );
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template< typename Errors, typename Rule >
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inline constexpr bool raise_on_failure< Errors, Rule, std::void_t< decltype( Errors::template raise_on_failure< Rule > ) > > = Errors::template raise_on_failure< Rule >;
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} // namespace internal
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template< typename Errors, template< typename... > class Base = normal, bool RequireMessage = true >
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struct must_if
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{
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template< typename Rule >
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struct control
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: Base< Rule >
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{
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template< typename ParseInput, typename... States >
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static void failure( const ParseInput& in, States&&... st ) noexcept( noexcept( Base< Rule >::failure( in, st... ) ) && !internal::raise_on_failure< Errors, Rule > )
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{
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if constexpr( internal::raise_on_failure< Errors, Rule > ) {
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raise( in, st... );
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}
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else {
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Base< Rule >::failure( in, st... );
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}
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}
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template< typename ParseInput, typename... States >
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[[noreturn]] static void raise( const ParseInput& in, [[maybe_unused]] States&&... st )
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{
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if constexpr( Errors::template message< Rule > != nullptr ) {
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constexpr const char* p = Errors::template message< Rule >;
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throw parse_error( p, in );
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#if defined( _MSC_VER )
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( (void)st, ... );
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#endif
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}
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else {
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if constexpr( !internal::has_error_message< Rule > ) {
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static_assert( !RequireMessage, "explicit error message required for Rule" );
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}
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Base< Rule >::raise( in, st... );
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}
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}
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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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#endif
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