Linq support for the specific case of string.ToLower().IsOneOf() and …

…similar patterns chaining operators off of ToLower/Upper

src/LinqTests/Acceptance/where_clauses.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using LinqTests.Acceptance.Support;
+using Marten;
 using Xunit.Abstractions;
 
 namespace LinqTests.Acceptance;
@@ -172,6 +173,12 @@ static where_clauses()
         @where(x => x.String.ToLower() == "red");
         @where(x => x.String.ToUpper() == "RED");
 
+        @where(x => x.String.ToLower().IsOneOf("red", "green"));
+        @where(x => x.String.ToLowerInvariant().IsOneOf("red", "green"));
+
+        @where(x => x.String.ToUpper().IsOneOf("RED", "GREEN"));
+        @where(x => x.String.ToUpperInvariant().IsOneOf("RED", "GREEN"));
+
         @where(x => x.PaddedString.Trim() == "red");
 
     }

src/LinqTests/Operators/is_one_of_operator.cs

@@ -3,16 +3,19 @@
 using System.Linq;
 using System.Linq.Expressions;
 using System.Text.Json.Serialization;
+using System.Threading.Tasks;
 using Marten;
 using Marten.Testing.Documents;
 using Marten.Testing.Harness;
 using Microsoft.FSharp.Core;
 using Shouldly;
+using Xunit.Abstractions;
 
 namespace LinqTests.Operators;
 
 public class is_one_of_operator: IntegrationContext
 {
+    private readonly ITestOutputHelper _output;
 
     public static TheoryData<Func<int[], Expression<Func<Target, bool>>>> SupportedIsOneOfWithIntArray =
         new()
@@ -126,8 +129,6 @@ public class is_one_of_operator: IntegrationContext
             validGuids => x => !x.FSharpGuidOption.In(validGuids)
         };
 
-
-
     [Theory]
     [MemberData(nameof(SupportedIsOneOfWithIntArray))]
     public void can_query_against_integers(Func<int[], Expression<Func<Target, bool>>> isOneOf) =>
@@ -307,8 +308,9 @@ Func<Target, T> select
 
 
 
-    public is_one_of_operator(DefaultStoreFixture fixture): base(fixture)
+    public is_one_of_operator(DefaultStoreFixture fixture, ITestOutputHelper output): base(fixture)
     {
+        _output = output;
         StoreOptions(_ =>
         {
             //_.Logger(new ConsoleMartenLogger());

src/LinqTests/playing.cs

@@ -4,18 +4,23 @@
 using Marten;
 using Marten.Testing.Documents;
 using Marten.Testing.Harness;
+using Xunit.Abstractions;
 
 namespace LinqTests;
 
 public class playing : IntegrationContext
 {
-    public playing(DefaultStoreFixture fixture) : base(fixture)
+    private readonly ITestOutputHelper _output;
+
+    public playing(DefaultStoreFixture fixture, ITestOutputHelper output) : base(fixture)
     {
+        _output = output;
     }
 
     [Fact]
     public async Task try_method_parsing()
     {
-        var data = await theSession.Query<Target>().Where(x => x.String.EqualsIgnoreCase("something")).ToListAsync();
+        theSession.Logger = new TestOutputMartenLogger(_output);
+        var data = await theSession.Query<Target>().Where(x => x.String.ToLower().IsOneOf("red", "blue")).ToListAsync();
     }
 }

src/Marten/Linq/Members/DuplicatedField.cs

@@ -232,6 +232,14 @@ public IQueryableMember FindMember(MemberInfo member)
                 {
                     RawLocator = $"upper({RawLocator})", TypedLocator = $"upper({RawLocator})"
                 },
+                nameof(string.ToLowerInvariant) => new StringMember(this, Casing.Default, member)
+                {
+                    RawLocator = $"lower({RawLocator})", TypedLocator = $"lower({RawLocator})"
+                },
+                nameof(string.ToUpperInvariant) => new StringMember(this, Casing.Default, member)
+                {
+                    RawLocator = $"upper({RawLocator})", TypedLocator = $"upper({RawLocator})"
+                },
                 _ => throw new BadLinqExpressionException($"Marten does not (yet) support the method {member.Name} in duplicated field querying")
             };
         }

src/Marten/Linq/Members/StringMember.cs

@@ -22,6 +22,7 @@ public StringMember(IQueryableMember parent, Casing casing, MemberInfo member):
     {
         TypedLocator = RawLocator;
         _lowerLocator = $"lower({RawLocator})";
+        MemberType = typeof(string);
     }
 
     public override IQueryableMember FindMember(MemberInfo member)
@@ -36,6 +37,14 @@ public override IQueryableMember FindMember(MemberInfo member)
             {
                 RawLocator = $"upper({RawLocator})", TypedLocator = $"upper({RawLocator})"
             },
+            nameof(string.ToLowerInvariant) => new StringMember(this, Casing.Default, member)
+            {
+                RawLocator = $"lower({RawLocator})", TypedLocator = $"lower({RawLocator})"
+            },
+            nameof(string.ToUpperInvariant) => new StringMember(this, Casing.Default, member)
+            {
+                RawLocator = $"upper({RawLocator})", TypedLocator = $"upper({RawLocator})"
+            },
             nameof(string.Trim) => new StringMember(this, Casing.Default, member)
             {
                 RawLocator = $"trim({RawLocator})", TypedLocator = $"trim({RawLocator})"

src/Marten/Linq/Parsing/MemberFinder.cs

@@ -52,6 +52,15 @@ protected override Expression VisitMethodCall(MethodCallExpression node)
             Members.Insert(0, LinqConstants.ArrayLength);
         }
 
+        // This is fugly!
+        if (node.Method.Name.IsOneOf([
+                nameof(String.ToLower), nameof(String.ToUpper), nameof(String.ToLowerInvariant),
+                nameof(String.ToUpperInvariant)
+            ]))
+        {
+            Members.Insert(0, node.Method);
+        }
+
         return base.VisitMethodCall(node);
     }