feat: Parser Combinator库和词法分析器 (#2)

Reviewed-on: https://git.bupt-hpc.cn/jackfiled/CanonSharp/pulls/2
Co-authored-by: jackfiled <xcrenchangjun@outlook.com>
Co-committed-by: jackfiled <xcrenchangjun@outlook.com>

CanonSharp.Combinator/Results/FailedResultWithError.cs

@@ -0,0 +1,22 @@
+using CanonSharp.Combinator.Abstractions;
+
+namespace CanonSharp.Combinator.Results;
+
+/// <summary>
+/// 错误类型的失败解析结果
+/// </summary>
+/// <typeparam name="TToken">输入流的类型</typeparam>
+/// <typeparam name="TState">输入流的读取类型</typeparam>
+/// <typeparam name="T">实际的结果类型</typeparam>
+internal sealed class FailedResultWithError<TToken, TState, T>(TState state) : FailedResult<TToken, T>
+    where TState : IReadState<TToken, TState>
+{
+    public override IReadState<TToken> State => state;
+
+    public override string Message => $"Unexpected state: {state}.";
+
+    public override FailedResult<TToken, TNext> Convert<TNext>()
+    {
+        return new FailedResultWithError<TToken, TState, TNext>(state);
+    }
+}

CanonSharp.Combinator/Results/FailedResultWithException.cs

@@ -0,0 +1,24 @@
+using CanonSharp.Combinator.Abstractions;
+
+namespace CanonSharp.Combinator.Results;
+
+/// <summary>
+/// 异常类型的失败解析结果
+/// </summary>
+/// <param name="exception">解析中发生的异常</param>
+/// <param name="state">当前输入流的状态</param>
+/// <typeparam name="TToken">输入流类型</typeparam>
+/// <typeparam name="TState">当前输入流状态的类型</typeparam>
+/// <typeparam name="T">解析结果的类型</typeparam>
+public class FailedResultWithException<TToken, TState, T>(Exception exception, TState state) : FailedResult<TToken, T>
+    where TState : IReadState<TToken, TState>
+{
+    public override IReadState<TToken> State => state;
+
+    public override ParseException Exception => new(ToString(), exception);
+
+    public override string Message => $"Exception occured: {exception}.";
+
+    public override FailedResult<TToken, TNext> Convert<TNext>()
+        => new FailedResultWithException<TToken, TState, TNext>(exception, state);
+}

CanonSharp.Combinator/Results/FailedResultWithMessage.cs

@@ -0,0 +1,24 @@
+using CanonSharp.Combinator.Abstractions;
+
+namespace CanonSharp.Combinator.Results;
+
+/// <summary>
+/// 消息类型的失败解析结果
+/// </summary>
+/// <param name="message">解析失败的消息</param>
+/// <param name="state">当前读取的状态</param>
+/// <typeparam name="TToken">输入流的类型</typeparam>
+/// <typeparam name="TState">读取状态类型</typeparam>
+/// <typeparam name="T">解析结果的类型</typeparam>
+internal sealed class FailedResultWithMessage<TToken, TState, T>(string message, TState state) : FailedResult<TToken, T>
+    where TState : IReadState<TToken, TState>
+{
+    public override IReadState<TToken> State => state;
+
+    public override string Message => message;
+
+    public override FailedResult<TToken, TNext> Convert<TNext>()
+    {
+        return new FailedResultWithMessage<TToken, TState, TNext>(message, state);
+    }
+}

CanonSharp.Combinator/Results/InternalSuccessfulResult.cs

@@ -0,0 +1,23 @@
+using CanonSharp.Combinator.Abstractions;
+
+namespace CanonSharp.Combinator.Results;
+
+/// <summary>
+/// 实际实现的解析成功结果
+/// </summary>
+/// <param name="result">解析结果</param>
+/// <param name="state">解析成功之后的下一个输入流状态</param>
+/// <typeparam name="TToken">输入流类型</typeparam>
+/// <typeparam name="TState">输入流的状态类型</typeparam>
+/// <typeparam name="T">解析结果的类型</typeparam>
+internal sealed class InternalSuccessfulResult<TToken, TState, T>(T result, TState state)
+    : SuccessfulResult<TToken, T>(result)
+    where TState : IReadState<TToken, TState>
+{
+    protected override ParseResult<TToken, TResult> RunNext<TNext, TResult>(Parser<TToken, TNext> parser,
+        Func<ParseResult<TToken, TNext>, ParseResult<TToken, TResult>> continuation)
+        => parser.Run(state, continuation);
+
+    public override ParseResult<TToken, TResult> Map<TResult>(Func<T, TResult> map)
+        => new InternalSuccessfulResult<TToken, TState, TResult>(map(Value), state);
+}