Dont anonymize Join nor default enums (#2847)

This pull request includes changes to enhance the handling of enums in
the `StructuralPrint` class, update the list of known functions, and
improve test coverage.

Enhancements to `StructuralPrint`:

*
[`src/libraries/Microsoft.PowerFx.Core/Logging/StructuralPrint.cs`](diffhunk://#diff-4760f19aba839606fcde0849467658572c272afd030c115afae8263986234a6dR9):
Added logic to handle default enums in the `Visit` method for
`DottedNameNode`, and included the `Enums` namespace.
[[1]](diffhunk://#diff-4760f19aba839606fcde0849467658572c272afd030c115afae8263986234a6dR9)
[[2]](diffhunk://#diff-4760f19aba839606fcde0849467658572c272afd030c115afae8263986234a6dR126-R134)

Updates to known functions:

*
[`src/libraries/Microsoft.PowerFx.Core/Texl/BuiltinFunctionsCore.cs`](diffhunk://#diff-5a3b8429b8a783e4a4f50cbc410c8c1d83eda1fc561760948b79fc8ce675a5baR20-R26):
Updated the `OtherKnownFunctions` list to include the `Join` function.

Improvements to test coverage:

*
[`src/tests/Microsoft.PowerFx.Core.Tests.Shared/FormatterTests.cs`](diffhunk://#diff-f6ab2187c7ce1b7dea3e0655fb70f738656098817671383d60e9233859294a34R8):
Added new test cases for the `Join` and `WeekNum` functions in
`TestStucturalPrintWithBinding`, and included the `Builtins` namespace.
[[1]](diffhunk://#diff-f6ab2187c7ce1b7dea3e0655fb70f738656098817671383d60e9233859294a34R8)
[[2]](diffhunk://#diff-f6ab2187c7ce1b7dea3e0655fb70f738656098817671383d60e9233859294a34R37-R46)
[[3]](diffhunk://#diff-f6ab2187c7ce1b7dea3e0655fb70f738656098817671383d60e9233859294a34R72-R101)

src/libraries/Microsoft.PowerFx.Core/Logging/StructuralPrint.cs

@@ -6,6 +6,7 @@
 using Microsoft.PowerFx.Core.Binding;
 using Microsoft.PowerFx.Core.Parser;
 using Microsoft.PowerFx.Core.Texl;
+using Microsoft.PowerFx.Core.Types.Enums;
 using Microsoft.PowerFx.Core.UtilityDataStructures;
 using Microsoft.PowerFx.Core.Utils;
 using Microsoft.PowerFx.Syntax;
@@ -121,7 +122,16 @@ public override LazyList<string> Visit(DottedNameNode node, Precedence parentPre
         {
             Contracts.AssertValue(node);
 
-            var separator = TexlParser.GetTokString(node.Token.Kind);
+            var separator = TexlParser.GetTokString(node.Token.Kind);
+            var nodeType = _binding?.GetType(node);
+
+            // If default enum, show it plain.
+            if (nodeType != null && 
+                nodeType.OptionSetInfo != null &&
+                EnumStoreBuilder.DefaultEnumSymbols.ContainsKey(nodeType.OptionSetInfo.EntityName.Value))
+            {
+                return LazyList<string>.Of(node.ToString());
+            }
 
             var values = node.Left.Accept(this, Precedence.Primary);
             values = values.With(separator);

src/libraries/Microsoft.PowerFx.Core/Texl/BuiltinFunctionsCore.cs

@@ -16,11 +16,14 @@ internal class BuiltinFunctionsCore
     {
         // This is the list of Power Apps functions that aren't supported/implemeted in Power Fx
         // Binder will recognize these functions names and return a "recognized but not yet supported function" message 
-        // instead of the classic "unknown or unsupported function".
+        // instead of the classic "unknown or unsupported function".
+
+        // This list also contains functions that are added to the interpreter at runtime and dont have their definitions
+        // included into the BuiltinFunctionsLibrary library. Examples: Set, Join.
         internal static readonly IReadOnlyCollection<string> OtherKnownFunctions = new HashSet<string>()
         {
             "Assert", "Back", "Choices", "ClearData", "Concurrent", "Confirm", "Copy", "DataSourceInfo", "Defaults", "Disable", "Distinct", "Download", "EditForm", "Enable", "Errors", "Exit",
-            "GroupBy", "HashTags", "IsMatch", "IsType", "JSON", "Launch", "LoadData", "Match", "MatchAll", "Navigate", "NewForm", "Notify", "PDF", "Param", "Pending", "Print", "ReadNFC",
+            "GroupBy", "HashTags", "IsMatch", "IsType", "Join", "JSON", "Launch", "LoadData", "Match", "MatchAll", "Navigate", "NewForm", "Notify", "PDF", "Param", "Pending", "Print", "ReadNFC",
             "RecordInfo", "Relate", "RemoveAll", "RemoveIf", "RequestHide", "Reset", "ResetForm", "Revert", "SaveData", "ScanBarcode", "Select", "SetFocus",
             "SetProperty", "ShowColumns", "State", "SubmitForm", "TraceValue", "Ungroup", "Unrelate", "Update", "UpdateContext", "UpdateIf", "User", "Validate", "ValidateRecord", "ViewForm",
             "Collect", "Clear", "Patch", "Remove", "ClearCollect", "Set"

src/tests/Microsoft.PowerFx.Core.Tests.Shared/FormatterTests.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using Microsoft.PowerFx.Core.Logging;
 using Microsoft.PowerFx.Core.Tests;
+using Microsoft.PowerFx.Core.Texl.Builtins;
 using Microsoft.PowerFx.Syntax;
 using Microsoft.PowerFx.Types;
 using Xunit;
@@ -40,7 +41,8 @@ public void TestStucturalPrint(string script, string expected)
                 flags: Flags.EnableExpressionChaining,
                 features: Features.PowerFxV1);
 
-            Assert.Equal(expected, StructuralPrint.Print(result.Root));
+            var actual = StructuralPrint.Print(result.Root);
+            Assert.Equal(expected, actual);
 
             // Test same cases via CheckResult
             var check = new CheckResult(new Engine(new PowerFxConfig()));
@@ -66,24 +68,36 @@ public void TestStucturalPrint(string script, string expected)
             "ForAll([1,2,3], ThisRecord.Value * 2)",
             "ForAll([ #$decimal$#, #$decimal$#, #$decimal$# ], #$firstname$#.#$righthandid$# * #$decimal$#)",
             "ForAll([ #$decimal$#, #$decimal$#, #$decimal$# ], #$LambdaFullRecord$#.#$righthandid$# * #$decimal$#)")]
+        [InlineData(
+            "Join(Table({a:1}), Table({a:1}), LeftRecord.a = RightRecord.a, JoinType.Inner, RightRecord.a As AAA)",
+            "Join(Table({ #$fieldname$#:#$decimal$# }), Table({ #$fieldname$#:#$decimal$# }), #$firstname$#.#$righthandid$# = #$firstname$#.#$righthandid$#, #$firstname$#.#$righthandid$#, #$firstname$#.#$righthandid$# As #$righthandid$#)",
+            "Join(Table({ #$fieldname$#:#$decimal$# }), Table({ #$fieldname$#:#$decimal$# }), #$LambdaField$#.#$righthandid$# = #$LambdaField$#.#$righthandid$#, JoinType.Inner, #$LambdaField$#.#$righthandid$# As #$righthandid$#)")]
+        [InlineData(
+            "WeekNum(Date(2020, 12, 8),StartOfWeek.Sunday)",
+            "WeekNum(Date(#$decimal$#, #$decimal$#, #$decimal$#), #$firstname$#.#$righthandid$#)",
+            "WeekNum(Date(#$decimal$#, #$decimal$#, #$decimal$#), StartOfWeek.Sunday)")]
 
         public void TestStucturalPrintWithBinding(string script, string beforebinding, string afterbinding)
         {
             var result = ParseScript(
                 script,
                 flags: Flags.EnableExpressionChaining);
 
-            Assert.Equal(beforebinding, StructuralPrint.Print(result.Root));
+            var actual = StructuralPrint.Print(result.Root);
+            Assert.Equal(beforebinding, actual);
+
+            var symbolTable = new SymbolTable();
+            symbolTable.AddFunction(new JoinFunction());
 
             // Test same cases via CheckResult
             var check = new CheckResult(new Engine());
 
             check.SetText(script, new ParserOptions { AllowsSideEffects = true })
-                .SetBindingInfo()
+                .SetBindingInfo(symbolTable)
                 .ApplyBinding();
 
-            var result2 = check.ApplyGetLogging();
-            Assert.Equal(afterbinding, result2);
+            actual = check.ApplyGetLogging();
+            Assert.Equal(afterbinding, actual);
         }
 
         private class TestSanitizer : ISanitizedNameProvider