feat: 正则词法识别器 (#1)

Reviewed-on: https://git.bupt-hpc.cn/jackfiled/CanonSharp/pulls/1
Co-authored-by: jackfiled <xcrenchangjun@outlook.com>
Co-committed-by: jackfiled <xcrenchangjun@outlook.com>

CanonSharp.Common/Abstractions/ISourceReader.cs

@@ -0,0 +1,17 @@
+namespace CanonSharp.Common.Abstractions;
+
+public interface ISourceReader
+{
+    /// <summary>
+    /// 偷看一下下一个字符
+    /// </summary>
+    /// <param name="c">看到的下一个字符</param>
+    /// <returns></returns>
+    public bool TryPeek(out char c);
+
+    /// <summary>
+    /// 读取下一个字符
+    /// </summary>
+    /// <returns></returns>
+    public char Read();
+}