Add in a regex parser so that the IDE can provide services around regex editing.

src/Workspaces/Core/Portable/EmbeddedLanguages/RegularExpressions/IRegexNodeVisitor.cs

@@ -0,0 +1,50 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+namespace Microsoft.CodeAnalysis.EmbeddedLanguages.RegularExpressions
+{
+    internal interface IRegexNodeVisitor
+    {
+        void Visit(RegexCompilationUnit node);
+        void Visit(RegexSequenceNode node);
+        void Visit(RegexTextNode node);
+        void Visit(RegexCharacterClassNode node);
+        void Visit(RegexNegatedCharacterClassNode node);
+        void Visit(RegexCharacterClassRangeNode node);
+        void Visit(RegexCharacterClassSubtractionNode node);
+        void Visit(RegexPosixPropertyNode node);
+        void Visit(RegexWildcardNode node);
+        void Visit(RegexZeroOrMoreQuantifierNode node);
+        void Visit(RegexOneOrMoreQuantifierNode node);
+        void Visit(RegexZeroOrOneQuantifierNode node);
+        void Visit(RegexLazyQuantifierNode node);
+        void Visit(RegexExactNumericQuantifierNode node);
+        void Visit(RegexOpenNumericRangeQuantifierNode node);
+        void Visit(RegexClosedNumericRangeQuantifierNode node);
+        void Visit(RegexAnchorNode node);
+        void Visit(RegexAlternationNode node);
+        void Visit(RegexSimpleGroupingNode node);
+        void Visit(RegexSimpleOptionsGroupingNode node);
+        void Visit(RegexNestedOptionsGroupingNode node);
+        void Visit(RegexNonCapturingGroupingNode node);
+        void Visit(RegexPositiveLookaheadGroupingNode node);
+        void Visit(RegexNegativeLookaheadGroupingNode node);
+        void Visit(RegexPositiveLookbehindGroupingNode node);
+        void Visit(RegexNegativeLookbehindGroupingNode node);
+        void Visit(RegexNonBacktrackingGroupingNode node);
+        void Visit(RegexCaptureGroupingNode node);
+        void Visit(RegexBalancingGroupingNode node);
+        void Visit(RegexConditionalCaptureGroupingNode node);
+        void Visit(RegexConditionalExpressionGroupingNode node);
+        void Visit(RegexSimpleEscapeNode node);
+        void Visit(RegexAnchorEscapeNode node);
+        void Visit(RegexCharacterClassEscapeNode node);
+        void Visit(RegexControlEscapeNode node);
+        void Visit(RegexHexEscapeNode node);
+        void Visit(RegexUnicodeEscapeNode node);
+        void Visit(RegexCaptureEscapeNode node);
+        void Visit(RegexKCaptureEscapeNode node);
+        void Visit(RegexOctalEscapeNode node);
+        void Visit(RegexBackreferenceEscapeNode node);
+        void Visit(RegexCategoryEscapeNode node);
+    }
+}