add ir emitter

StgSharp.RegularAnalysis/TextRegex/RegexInterpreter.IRGenerate.cs

@@ -28,23 +28,72 @@
 using StgSharp.RegularAnalysis.Abstraction;
 using System;
 using System.Collections.Generic;
+using System.Data;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using System.Xml;
 
 namespace StgSharp.RegularAnalysis.TextRegex
 {
     public partial class RegexInterpreter
     {
 
+        private List<RegexIR> EmptyIR { get; } = [];
+
         internal List<RegexIR> GenerateIR(
                                AbstractSyntaxTree<RegexAstNode, RegexElementLabel> tree
         )
         {
-            using TreeEnumerator<RegexAstNode, RegexElementLabel> enumerator = new(tree);
-            while (enumerator.MoveNext())
+            return GenerateIRRecursion(tree.Root, 0);
+        }
+
+        private List<RegexIR> GenerateIRRecursion(
+                              RegexAstNode node,
+                              int depth
+        )
+        {
+            if (depth > 1024) {
+                throw new OverflowException("Regex parse exceeds maximum recursion depth");
+            }
+            int curDepth = depth;
+            RegexAstNode left = node.Left;
+            RegexAstNode right = node.Right;
+            List<RegexIR> leftIR = EmptyIR;
+            List<RegexIR> rightIR = EmptyIR;
+
+            bool isLeftOperator = !RegexAstNode.IsNullOrEmpty(left) &&
+                                  (left.Source.Flag & RegexElementLabel.OPERATOR) != 0;
+            bool isRightOperator = !RegexAstNode.IsNullOrEmpty(right) &&
+                                   (right.Source.Flag & RegexElementLabel.OPERATOR) != 0;
+
+            Token<RegexElementLabel> token = node.Source;
+
+            switch (node.Source.Flag)
             {
-                if (true) { }
+                case RegexElementLabel.GROUP_BEGIN:
+                    string group_source = token.Value;
+                    bool is_group = group_source.Length == 1;
+                    string group_name = group_source.StartsWith(@"(?<", StringComparison.Ordinal) ?
+                                        group_source[3..^2] :
+                                        string.Empty;
+
+                    List<RegexIR> groupIR = [];
+                    rightIR = GenerateIRRecursion(right, curDepth + 1);
+                    groupIR.Add(RegexIR.Try(rightIR.Count));
+                    groupIR.AddRange(rightIR);
+                    groupIR.Add(RegexIR.Condition(2, 1));
+                    groupIR.Add(RegexIR.PopLevel(false));
+                    groupIR.Add(RegexIR.PopLevel(true));
+                    break;
+                case RegexElementLabel.COUNT:
+                    break;
+                case RegexElementLabel.CONCAT:
+                    break;
+                case RegexElementLabel.ALT:
+                    break;
+                default:
+                    break;
             }
 
             return [];