Limited regular expressions

src/libraries/Microsoft.PowerFx.Core/Binding/BinderUtils.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license.
 
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using Microsoft.CodeAnalysis;
 using Microsoft.PowerFx.Core.App.Controls;
@@ -14,6 +15,7 @@
 using Microsoft.PowerFx.Core.Localization;
 using Microsoft.PowerFx.Core.Logging.Trackers;
 using Microsoft.PowerFx.Core.Texl;
+using Microsoft.PowerFx.Core.Texl.Builtins;
 using Microsoft.PowerFx.Core.Types;
 using Microsoft.PowerFx.Core.Types.Enums;
 using Microsoft.PowerFx.Core.Utils;
@@ -1540,6 +1542,49 @@ public static bool TryGetConstantValue(CheckTypesContext context, TexlNode node,
                             nodeValue = string.Join(string.Empty, parameters);
                             return true;
                         }
+                    }
+                    else if (callNode.Head.Name.Value == BuiltinFunctionsCore.Char.Name && callNode.Args.Children.Count == 1)
+                    {
+                        int val = -1;
+
+                        if (callNode.Args.Children[0].Kind == NodeKind.DecLit)
+                        {
+                            val = (int)((DecLitNode)callNode.Args.Children[0]).ActualDecValue;
+                        }
+                        else if (callNode.Args.Children[0].Kind == NodeKind.NumLit)
+                        {
+                            val = (int)((NumLitNode)callNode.Args.Children[0]).ActualNumValue;
+                        }
+
+                        if (val < 1 || val > 255)
+                        {
+                            return false;
+                        }
+
+                        nodeValue = ((char)val).ToString();
+                        return true;
+                    }
+                    else if (callNode.Head.Name.Value == BuiltinFunctionsCore.UniChar.Name && callNode.Args.Children.Count == 1)
+                    {
+                        int val = -1;
+
+                        if (callNode.Args.Children[0].Kind == NodeKind.DecLit)
+                        {
+                            val = (int)((DecLitNode)callNode.Args.Children[0]).ActualDecValue;
+                        }
+                        else if (callNode.Args.Children[0].Kind == NodeKind.NumLit)
+                        {
+                            val = (int)((NumLitNode)callNode.Args.Children[0]).ActualNumValue;
+                        }
+
+                        // partial surrogate pair not supported, consistent with interpreter UniChar implementation
+                        if (val < 1 || val > 0x10FFFF || (val >= 0xD800 && val <= 0xDFFF))
+                        {
+                            return false;
+                        }
+
+                        nodeValue = char.ConvertFromUtf32(val);
+                        return true;
                     }
 
                     break;

src/libraries/Microsoft.PowerFx.Core/Localization/Strings.cs

@@ -732,7 +732,47 @@ internal static class TexlStrings
         public static ErrorResourceKey ErrDecimalRequiresPowerFxV1 = new ErrorResourceKey("ErrDecimalNeedsPowerFxV1");
 
         public static ErrorResourceKey ErrInvalidRegEx = new ErrorResourceKey("ErrInvalidRegEx");
+        public static ErrorResourceKey ErrInvalidRegExBadInlineOptions = new ErrorResourceKey("ErrInvalidRegExBadInlineOptions");
+        public static ErrorResourceKey ErrInvalidRegExInlineOptionNotAtStart = new ErrorResourceKey("ErrInvalidRegExInlineOptionNotAtStart");
+        public static ErrorResourceKey ErrInvalidRegExBadOctal = new ErrorResourceKey("ErrInvalidRegExBadOctal");
+        public static ErrorResourceKey ErrInvalidRegExBadCurly = new ErrorResourceKey("ErrInvalidRegExBadCurly");
+        public static ErrorResourceKey ErrInvalidRegExBadSquare = new ErrorResourceKey("ErrInvalidRegExBadSquare");
+        public static ErrorResourceKey ErrInvalidRegExBadParen = new ErrorResourceKey("ErrInvalidRegExBadParen");
+        public static ErrorResourceKey ErrInvalidRegExBadEscapeInsideCharacterClass = new ErrorResourceKey("ErrInvalidRegExBadEscapeInsideCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExBadEscapeInsideNegativeCharacterClass = new ErrorResourceKey("ErrInvalidRegExBadEscapeInsideNegativeCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExBadEscapeOutsideCharacterClass = new ErrorResourceKey("ErrInvalidRegExBadEscapeOutsideCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExRepeatInCharClass = new ErrorResourceKey("ErrInvalidRegExRepeatInCharClass");
+        public static ErrorResourceKey ErrInvalidRegExRepeatedInlineOption = new ErrorResourceKey("ErrInvalidRegExRepeatedInlineOption");
+        public static ErrorResourceKey ErrInvalidRegExInlineOptionConflictsWithNumberedSubMatches = new ErrorResourceKey("ErrInvalidRegExInlineOptionConflictsWithNumberedSubMatches");
+        public static ErrorResourceKey ErrInvalidRegExConflictingInlineOptions = new ErrorResourceKey("ErrInvalidRegExConflictingInlineOptions");
+        public static ErrorResourceKey ErrInvalidRegExBadQuantifier = new ErrorResourceKey("ErrInvalidRegExBadQuantifier");
+        public static ErrorResourceKey ErrInvalidRegExBadBackRefSelfReferencing = new ErrorResourceKey("ErrInvalidRegExBadBackRefSelfReferencing");
+        public static ErrorResourceKey ErrInvalidRegExBadBackRefNotDefined = new ErrorResourceKey("ErrInvalidRegExBadBackRefNotDefined");
+        public static ErrorResourceKey ErrInvalidRegExBadBackRefNumber = new ErrorResourceKey("ErrInvalidRegExBadBackRefNumber");
+        public static ErrorResourceKey ErrInvalidRegExBadBalancing = new ErrorResourceKey("ErrInvalidRegExBadBalancing");
+        public static ErrorResourceKey ErrInvalidRegExBadSingleQuoteNamedCapture = new ErrorResourceKey("ErrInvalidRegExBadSingleQuoteNamedCapture");
+        public static ErrorResourceKey ErrInvalidRegExBadEscape = new ErrorResourceKey("ErrInvalidRegExBadEscape");
+        public static ErrorResourceKey ErrInvalidRegExBadConditional = new ErrorResourceKey("ErrInvalidRegExBadConditional");
+        public static ErrorResourceKey ErrInvalidRegExBadNamedCaptureAlreadyExists = new ErrorResourceKey("ErrInvalidRegExBadNamedCaptureAlreadyExists");
+        public static ErrorResourceKey ErrInvalidRegExBadNamedCaptureName = new ErrorResourceKey("ErrInvalidRegExBadNamedCaptureName");
+        public static ErrorResourceKey ErrInvalidRegExBadCharacterClassLiteralSquareBracket = new ErrorResourceKey("ErrInvalidRegExBadCharacterClassLiteralSquareBracket");
+        public static ErrorResourceKey ErrInvalidRegExUnclosedCaptureGroups = new ErrorResourceKey("ErrInvalidRegExUnclosedCaptureGroups");
+        public static ErrorResourceKey ErrInvalidRegExUnclosedInlineComment = new ErrorResourceKey("ErrInvalidRegExUnclosedInlineComment");
+        public static ErrorResourceKey ErrInvalidRegExUnopenedCaptureGroups = new ErrorResourceKey("ErrInvalidRegExUnopenedCaptureGroups");
+        public static ErrorResourceKey ErrInvalidRegExUnclosedCharacterClass = new ErrorResourceKey("ErrInvalidRegExUnclosedCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExMixingNamedAndNumberedSubMatches = new ErrorResourceKey("ErrInvalidRegExMixingNamedAndNumberedSubMatches");
+        public static ErrorResourceKey ErrInvalidRegExNumberedSubMatchesDisabled = new ErrorResourceKey("ErrInvalidRegExNumberedSubMatchesDisabled");
+        public static ErrorResourceKey ErrInvalidRegExBadUnsupportedCharacterClassSubtraction = new ErrorResourceKey("ErrInvalidRegExBadUnsupportedCharacterClassSubtraction");
+        public static ErrorResourceKey ErrInvalidRegExOpenParenInComment = new ErrorResourceKey("ErrInvalidRegExOpenParenInComment");
+        public static ErrorResourceKey ErrInvalidRegExLiteralHyphenInCharacterClass = new ErrorResourceKey("ErrInvalidRegExLiteralHyphenInCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExBackRefInCharacterClass = new ErrorResourceKey("ErrInvalidRegExBackRefInCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExUnescapedCharInCharacterClass = new ErrorResourceKey("ErrInvalidRegExUnescapedCharInCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExUnescapedParensInCharacterClass = new ErrorResourceKey("ErrInvalidRegExUnescapedParensInCharacterClass");
+        public static ErrorResourceKey ErrInvalidRegExBadUnicodeCategory = new ErrorResourceKey("ErrInvalidRegExBadUnicodeCategory");
+        public static ErrorResourceKey ErrInvalidRegExEmptyCharacterClass = new ErrorResourceKey("ErrInvalidRegExEmptyCharacterClass");
+
         public static ErrorResourceKey ErrVariableRegEx = new ErrorResourceKey("ErrVariableRegEx");
+        public static ErrorResourceKey ErrVariableRegExOptions = new ErrorResourceKey("ErrVariableRegExOptions");
         public static ErrorResourceKey InfoRegExCaptureNameHidesPredefinedFullMatchField = new ErrorResourceKey("InfoRegExCaptureNameHidesPredefinedFullMatchField");
         public static ErrorResourceKey InfoRegExCaptureNameHidesPredefinedSubMatchesField = new ErrorResourceKey("InfoRegExCaptureNameHidesPredefinedSubMatchesField");
         public static ErrorResourceKey InfoRegExCaptureNameHidesPredefinedStartMatchField = new ErrorResourceKey("InfoRegExCaptureNameHidesPredefinedStartMatchField");

src/libraries/Microsoft.PowerFx.Core/Public/Values/StringValue.cs

@@ -36,11 +36,6 @@ public override void Visit(IValueVisitor visitor)
             visitor.Visit(this);
         }
 
-        internal StringValue ToLower()
-        {
-            return new StringValue(IRContext.NotInSource(FormulaType.String), Value.ToLowerInvariant());
-        }
-
         public override void ToExpression(StringBuilder sb, FormulaValueSerializerSettings settings)
         {
             sb.Append($"\"{CharacterUtils.ExcelEscapeString(Value)}\"");