mainly theoratical work on semi, add regex sample

src/StgSharp.RegularAnalysis/Text/TextRegexSourceGen.GenClass.MultiIR.cs

@@ -71,15 +71,15 @@ namespace StgSharp.RegularAnalysis.Text
                             .AppendLine(@"do")
                             .AppendLine(@"{")
                             .AppendLine(@$"int {cur_ptr}, {begin_ptr} = {current_ptr};")
-                            .AppendLine();
+                            .AppendLine($@"{ROS_char} rest = ");
 
             string finder = find.IsFirst ? "FirstIndexOf" : "LastIndexOf";
 
             if (scan_win[1] is RegexMatchSeqIR seq)
             {
-                string seq_pat = FormatStringLiteral(seq.Pattern);
+                string seq_pat = FormatStringLiteral(find.Pattern + seq.Pattern);
                 _ = main_emitter.AppendLine(@$"//Match sequence:{seq_pat} at current pos")
-                                .AppendLine(string.Empty());
+                                .AppendLine($@"if(  )");
             }
 
             _ = main_emitter.AppendLine("}").AppendLine(string.Empty);

test/SingleFile/regex.cs

@@ -0,0 +1,55 @@
+using System;
+
+//abc
+static void Match_ABC(ReadOnlySpan<char> input)
+{
+    int ptr = 0;
+    int region_start = ptr;
+    int region_end = region_start;
+
+    const string pattern = @"abc";
+    if(input[0..3].SequenceEqual(pattern))
+    {
+        ptr += 3;
+        region_end = ptr;
+    }
+}
+
+//a[abc]d
+static void Match_A_charset_ABC_C(ReadOnlySpan<char> input)
+{
+    int ptr = 0;
+    int region_start = ptr;
+    int region_end = region_start;
+
+    if(input[0] == 'a' && (input[1] == 'a' || input[1] == 'b' || input[1] == 'c') && input[2] == 'd')
+    {
+        ptr += 3;
+        region_end = ptr;
+    }
+}
+
+//[abc]
+static void Match_charset_ABC(ReadOnlySpan<char> input)
+{
+    int ptr = 0;
+    int region_start = ptr;
+    int region_end = region_start;
+
+    if(input[0] == 'a' || input[0] == 'b' || input[0] == 'c')
+    {
+        ptr += 1;
+        region_end = ptr;
+    }
+}
+
+//.
+static void Match_Dot(ReadOnlySpan<char> input)
+{
+    int ptr = 0;
+    int region_start = ptr;
+    int region_end = region_start;
+
+        ptr += 1;
+        region_end = ptr;
+}