newline.hpp

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// Copyright (C) 2020-2023 Jonathan Müller and lexy contributors
// SPDX-License-Identifier: BSL-1.0
 
#ifndef LEXY_DSL_NEWLINE_HPP_INCLUDED
#define LEXY_DSL_NEWLINE_HPP_INCLUDED
 
#include <lexy/dsl/base.hpp>
#include <lexy/dsl/literal.hpp>
#include <lexy/dsl/token.hpp>
 
namespace lexy
{
struct expected_newline
{
    static LEXY_CONSTEVAL auto name()
    {
        return "expected newline";
    }
};
} // namespace lexy
 
namespace lexyd
{
struct _nl
: LEXY_DECAY_DECLTYPE(literal_set(LEXY_LIT("\n"), LEXY_LIT("\r\n")).error<lexy::expected_newline>)
{};
 
constexpr auto newline = _nl{};
} // namespace lexyd
 
namespace lexyd
{
struct _eol : branch_base
{
    template <typename Reader>
    struct bp
    {
        constexpr bool try_parse(const void*, Reader reader)
        {
            return reader.peek() == Reader::encoding::eof()
                   || lexy::try_match_token(newline, reader);
        }
 
        template <typename Context>
        constexpr void cancel(Context&)
        {}
 
        template <typename NextParser, typename Context, typename... Args>
        LEXY_PARSER_FUNC bool finish(Context& context, Reader& reader, Args&&... args)
        {
            if (reader.peek() == Reader::encoding::eof())
            {
                auto pos = reader.position();
                context.on(_ev::token{}, lexy::eof_token_kind, pos, pos);
                return NextParser::parse(context, reader, LEXY_FWD(args)...);
            }
            else
            {
                // Note that we're re-doing the parsing for newline,
                // this looks at most at two characters, so it doesn't really matter.
                return lexy::parser_for<_nl, NextParser>::parse(context, reader, LEXY_FWD(args)...);
            }
        }
    };
 
    template <typename NextParser>
    struct p
    {
        template <typename Context, typename Reader, typename... Args>
        LEXY_PARSER_FUNC static bool parse(Context& context, Reader& reader, Args&&... args)
        {
            return bp<Reader>{}.template finish<NextParser>(context, reader, LEXY_FWD(args)...);
        }
    };
};
 
constexpr auto eol = _eol{};
} // namespace lexyd
 
#endif // LEXY_DSL_NEWLINE_HPP_INCLUDED