mainly theoratical work

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

@@ -64,10 +64,25 @@ namespace StgSharp.RegularAnalysis.Text
             if (scan_win[0] is not RegexFindSeqIR find) {
                 return -1;
             }
+            const string cur_ptr = "cur_ptr",
+                begin_ptr = "begin_ptr";
             _ = main_emitter.AppendLine()
                             .AppendLine(@$"//Find sequence:{FormatStringLiteral(find.Pattern)} at any pos")
                             .AppendLine(@"do")
-                            .AppendLine(@"{");
+                            .AppendLine(@"{")
+                            .AppendLine(@$"int {cur_ptr}, {begin_ptr} = {current_ptr};")
+                            .AppendLine();
+
+            string finder = find.IsFirst ? "FirstIndexOf" : "LastIndexOf";
+
+            if (scan_win[1] is RegexMatchSeqIR seq)
+            {
+                string seq_pat = FormatStringLiteral(seq.Pattern);
+                _ = main_emitter.AppendLine(@$"//Match sequence:{seq_pat} at current pos")
+                                .AppendLine(string.Empty());
+            }
+
+            _ = main_emitter.AppendLine("}").AppendLine(string.Empty);
             return 1;
         }
 

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

@@ -24,7 +24,7 @@ namespace StgSharp.RegularAnalysis.Text
     internal partial class TextRegexSourceGen
     {
 
-        private const string current_ptr = "current_ptr";
+        private const string current_ptr = "cur_ptr_global";
         private const string offset = "offset";
         private const string orig_text = "text";
 
@@ -39,12 +39,10 @@ namespace StgSharp.RegularAnalysis.Text
             RegexInfo info = source.Info;
             List<RegexIR> ir = source.IRs;
             ReadOnlySpan<RegexIR> ir_sp = CollectionsMarshal.AsSpan(ir);
-            RegexIR[] window = new RegexIR[8];
-            Span<RegexIR> scan_win = window;
 
             SequenceEmitter<string> match_e = new();
             int index = 0;
-            int end = FindRrgionEnd(ir_sp, index);
+            int end = FindRegionEnd(ir_sp, index);
             ReadOnlySpan<RegexIR> region = ir_sp[0..end];
 
             while (true)
@@ -55,7 +53,7 @@ namespace StgSharp.RegularAnalysis.Text
                     break;
                 }
                 index = end;
-                end = FindRrgionEnd(ir_sp, end);
+                end = FindRegionEnd(ir_sp, end);
                 region = ir_sp[index..end];
             }
 
@@ -90,7 +88,7 @@ namespace StgSharp.RegularAnalysis.Text
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static int FindRrgionEnd(
+        private static int FindRegionEnd(
                            ReadOnlySpan<RegexIR> ir_sp,
                            int current
         )

src/StgSharp.RegularAnalysis/Text/TextRegexSourceGen.GenContext.cs

@@ -32,8 +32,14 @@ namespace StgSharp.RegularAnalysis.Text
             private const string __remain_cur = "__remain_cur";
             private const string __find_result = "__find_result";
 
-            private readonly Dictionary<string, int> _search_value_name = [];
-            private int _min_search_value_index;
+            private int _min_region_begin_index;
+
+            public string MakeNewRegionBegin()
+            {
+                string name = $"__region_begin_{_min_region_begin_index}";
+                _min_region_begin_index++;
+                return name;
+            }
 
             public string CurChar
             {
@@ -44,19 +50,6 @@ namespace StgSharp.RegularAnalysis.Text
                 }
             }
 
-            public int MakeNewSearchValue(
-                       string seq
-            )
-            {
-                if (_search_value_name.TryGetValue(seq, out int idx)) {
-                    return idx;
-                }
-                idx = _min_search_value_index;
-                _min_search_value_index++;
-                _search_value_name.Add(seq, idx);
-                return idx;
-            }
-
             public string FindResult
             {
                 get