24 lines
1011 B
C#
24 lines
1011 B
C#
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using CanonSharp.Combinator.Abstractions;
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namespace CanonSharp.Combinator.Parsers.Modifiers;
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/// <summary>
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/// 尝试的解析器
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/// 当成功时直接返回原结果
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/// 当失败时调用resume函数处理失败结果并返回成功结果
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/// </summary>
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/// <param name="parser">上游解析器</param>
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/// <param name="resume">处理失败结果的恢复函数</param>
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/// <typeparam name="TToken">输入流令牌</typeparam>
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/// <typeparam name="T">解析器返回结果类型</typeparam>
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internal sealed class TryParser<TToken, T>(Parser<TToken, T> parser, Func<FailedResult<TToken, T>, T> resume)
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: ModifiedParser<TToken, T, T>(parser)
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{
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protected override ParseResult<TToken, T> Succeed<TState>(TState state,
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SuccessfulResult<TToken, T> successfulResult)
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=> successfulResult;
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protected override ParseResult<TToken, T> Fail<TState>(TState state, FailedResult<TToken, T> failedResult)
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=> ParseResultBuilder.Succeed<TToken, TState, T>(resume(failedResult), state);
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}
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