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/Parsers/Primitives/TakeParser.cs

@@ -0,0 +1,23 @@
+using CanonSharp.Combinator.Abstractions;
+using CanonSharp.Combinator.Extensions;
+
+namespace CanonSharp.Combinator.Parsers.Primitives;
+
+/// <summary>
+/// 解析指定数量的解析器
+/// </summary>
+/// <param name="count">需要解析的数量</param>
+/// <typeparam name="TToken">输入流类型</typeparam>
+internal sealed class TakeParser<TToken>(int count) : PrimitiveParser<TToken, IEnumerable<TToken>>
+{
+    protected override ParseResult<TToken, IEnumerable<TToken>> Run<TState>(TState state)
+    {
+        List<TState> result = state.AsEnumerable<TToken, TState>().Take(count).ToList();
+
+        return result.Count == count
+            ? ParseResultBuilder.Succeed<TToken, TState, IEnumerable<TToken>>(result.Select(s => s.Current),
+                result.Count == 0 ? state : result.Last().Next)
+            : ParseResultBuilder.Fail<TToken, TState, IEnumerable<TToken>>("An input does not have required length.",
+                state);
+    }
+}