Add Roslyn incremental source generator samples

.gitignore

@@ -137,6 +137,7 @@ publish/
 
 # NuGet Packages
 *.nupkg
+.nuget/
 # The packages folder can be ignored because of Package Restore
 **/packages/*
 # except build/, which is used as an MSBuild target.

csharp/roslyn-sdk/SourceGenerators/CsvGenerator/CsvGenerator.Test/CsvGenerator.Test.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.XUnit" Version="1.1.2" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.10.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\CsvGenerator\CsvGenerator.csproj" />
+  </ItemGroup>
+
+</Project>

csharp/roslyn-sdk/SourceGenerators/CsvGenerator/CsvGenerator.Test/CsvGeneratorTests.cs

@@ -0,0 +1,145 @@
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Testing;
+using Microsoft.CodeAnalysis.Testing;
+using Microsoft.CodeAnalysis.Text;
+using Xunit;
+using System.Text;
+
+namespace CsvGenerator.Test;
+
+public class CsvGeneratorTests
+{
+    [Fact]
+    public async Task CsvWithHeadersAndRows_GeneratesClass()
+    {
+        string csvContent = "Name,Country\nTokyo,Japan\nDelhi,India\n";
+
+        string expectedGenerated = @"// <auto-generated />
+
+namespace CsvGenerated
+{
+    /// <summary>Strongly-typed class generated from Cities.csv.</summary>
+    public sealed class Cities
+    {
+        public string Name { get; }
+        public string Country { get; }
+
+        private Cities(string name, string country)
+        {
+            Name = name;
+            Country = country;
+        }
+
+        /// <summary>All rows from the CSV data.</summary>
+        public static global::System.Collections.Generic.IReadOnlyList<Cities> All { get; } =
+            new Cities[]
+            {
+                new Cities(""Tokyo"", ""Japan""),
+                new Cities(""Delhi"", ""India""),
+            };
+
+        public override string ToString() =>
+            $""Name={Name}, Country={Country}"";
+    }
+}
+";
+
+        var test = new CSharpSourceGeneratorTest<CsvIncrementalGenerator, DefaultVerifier>
+        {
+            TestCode = "// Intentionally empty, CSV generator does not need C# input.",
+            ReferenceAssemblies = ReferenceAssemblies.Net.Net80,
+        };
+
+        test.TestState.AdditionalFiles.Add(("Data/Cities.csv", csvContent));
+
+        test.TestState.GeneratedSources.Add(
+            (typeof(CsvIncrementalGenerator), "Cities.g.cs", expectedGenerated));
+
+        await test.RunAsync();
+    }
+
+    [Fact]
+    public async Task CsvWithHeaderOnly_NoOutput()
+    {
+        // Only a header row, no data rows – generator should not produce output.
+        string csvContent = "Name,Country\n";
+
+        var test = new CSharpSourceGeneratorTest<CsvIncrementalGenerator, DefaultVerifier>
+        {
+            TestCode = "// Intentionally empty.",
+            ReferenceAssemblies = ReferenceAssemblies.Net.Net80,
+        };
+
+        test.TestState.AdditionalFiles.Add(("Data/Cities.csv", csvContent));
+
+        // No generated sources expected.
+        await test.RunAsync();
+    }
+
+    [Fact]
+    public async Task NonCsvAdditionalFile_IsIgnored()
+    {
+        var test = new CSharpSourceGeneratorTest<CsvIncrementalGenerator, DefaultVerifier>
+        {
+            TestCode = "// Intentionally empty.",
+            ReferenceAssemblies = ReferenceAssemblies.Net.Net80,
+        };
+
+        test.TestState.AdditionalFiles.Add(("Data/readme.txt", "This is not a CSV file."));
+
+        // No generated sources expected.
+        await test.RunAsync();
+    }
+
+    [Fact]
+    public async Task CsvWithThreeColumns_GeneratesAllProperties()
+    {
+        string csvContent = "Id,Name,Score\n1,Alice,95\n2,Bob,87\n";
+
+        string expectedGenerated = @"// <auto-generated />
+
+namespace CsvGenerated
+{
+    /// <summary>Strongly-typed class generated from Students.csv.</summary>
+    public sealed class Students
+    {
+        public string Id { get; }
+        public string Name { get; }
+        public string Score { get; }
+
+        private Students(string id, string name, string score)
+        {
+            Id = id;
+            Name = name;
+            Score = score;
+        }
+
+        /// <summary>All rows from the CSV data.</summary>
+        public static global::System.Collections.Generic.IReadOnlyList<Students> All { get; } =
+            new Students[]
+            {
+                new Students(""1"", ""Alice"", ""95""),
+                new Students(""2"", ""Bob"", ""87""),
+            };
+
+        public override string ToString() =>
+            $""Id={Id}, Name={Name}, Score={Score}"";
+    }
+}
+";
+
+        var test = new CSharpSourceGeneratorTest<CsvIncrementalGenerator, DefaultVerifier>
+        {
+            TestCode = "// Intentionally empty.",
+            ReferenceAssemblies = ReferenceAssemblies.Net.Net80,
+        };
+
+        test.TestState.AdditionalFiles.Add(("Data/Students.csv", csvContent));
+
+        test.TestState.GeneratedSources.Add(
+            (typeof(CsvIncrementalGenerator), "Students.g.cs", expectedGenerated));
+
+        await test.RunAsync();
+    }
+}

csharp/roslyn-sdk/SourceGenerators/CsvGenerator/CsvGenerator/CsvGenerator.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+    <EnforceExtendedAnalyzerRules>true</EnforceExtendedAnalyzerRules>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.10.0" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.4" PrivateAssets="all" />
+  </ItemGroup>
+
+</Project>

csharp/roslyn-sdk/SourceGenerators/CsvGenerator/CsvGenerator/CsvIncrementalGenerator.cs

@@ -0,0 +1,193 @@
+#nullable enable
+
+using System.Collections.Immutable;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Text;
+
+namespace CsvGenerator;
+
+/// <summary>
+/// A source generator that reads <c>.csv</c> additional files and produces a
+/// strongly-typed C# class for each one.  The first row of the CSV is treated
+/// as column headers (property names) and every subsequent row becomes a static
+/// instance exposed through a generated <c>All</c> property.
+/// </summary>
+[Generator]
+public class CsvIncrementalGenerator : IIncrementalGenerator
+{
+    public void Initialize(IncrementalGeneratorInitializationContext context)
+    {
+        // Filter additional files to only .csv files.
+        IncrementalValuesProvider<AdditionalText> csvFiles =
+            context.AdditionalTextsProvider
+                   .Where(static file => Path.GetExtension(file.Path)
+                                             .Equals(".csv", System.StringComparison.OrdinalIgnoreCase));
+
+        // Read file content and pair with file name.
+        IncrementalValuesProvider<(string ClassName, string Text)?> csvData =
+            csvFiles.Select(static (file, ct) =>
+            {
+                string? text = file.GetText(ct)?.ToString();
+                if (text is null)
+                    return null;
+
+                string className = Path.GetFileNameWithoutExtension(file.Path);
+                return ((string ClassName, string Text)?)(className, text);
+            });
+
+        // Generate source for each CSV file.
+        context.RegisterSourceOutput(csvData, static (spc, csv) =>
+        {
+            if (csv is null)
+                return;
+
+            string? source = GenerateClassFromCsv(csv.Value.ClassName, csv.Value.Text);
+            if (source is not null)
+            {
+                spc.AddSource($"{csv.Value.ClassName}.g.cs", SourceText.From(source, Encoding.UTF8));
+            }
+        });
+    }
+
+    private static string? GenerateClassFromCsv(string className, string csvText)
+    {
+        string[] lines = csvText.Split(new[] { "\r\n", "\n" }, System.StringSplitOptions.RemoveEmptyEntries);
+        if (lines.Length < 2) // Need at least a header and one data row.
+            return null;
+
+        string[] headers = ParseCsvLine(lines[0]);
+        if (headers.Length == 0)
+            return null;
+
+        var sb = new StringBuilder();
+        sb.AppendLine("// <auto-generated />");
+        sb.AppendLine();
+        sb.AppendLine("namespace CsvGenerated");
+        sb.AppendLine("{");
+        sb.AppendLine($"    /// <summary>Strongly-typed class generated from {className}.csv.</summary>");
+        sb.AppendLine($"    public sealed class {className}");
+        sb.AppendLine("    {");
+
+        // Properties (all strings for simplicity)
+        foreach (string header in headers)
+        {
+            sb.AppendLine($"        public string {SanitizeIdentifier(header)} {{ get; }}");
+        }
+
+        sb.AppendLine();
+
+        // Constructor
+        sb.Append($"        private {className}(");
+        sb.Append(string.Join(", ", headers.Select(h => $"string {CamelCase(SanitizeIdentifier(h))}")));
+        sb.AppendLine(")");
+        sb.AppendLine("        {");
+        foreach (string header in headers)
+        {
+            string prop = SanitizeIdentifier(header);
+            sb.AppendLine($"            {prop} = {CamelCase(prop)};");
+        }
+        sb.AppendLine("        }");
+        sb.AppendLine();
+
+        // All property – static list of rows
+        sb.AppendLine("        /// <summary>All rows from the CSV data.</summary>");
+        sb.AppendLine($"        public static global::System.Collections.Generic.IReadOnlyList<{className}> All {{ get; }} =");
+        sb.AppendLine($"            new {className}[]");
+        sb.AppendLine("            {");
+
+        for (int i = 1; i < lines.Length; i++)
+        {
+            string[] values = ParseCsvLine(lines[i]);
+            // Pad or trim to match header count.
+            string[] row = new string[headers.Length];
+            for (int j = 0; j < headers.Length; j++)
+            {
+                row[j] = j < values.Length ? values[j] : string.Empty;
+            }
+
+            sb.Append($"                new {className}(");
+            sb.Append(string.Join(", ", row.Select(EscapeString)));
+            sb.AppendLine("),");
+        }
+
+        sb.AppendLine("            };");
+
+        // ToString override
+        sb.AppendLine();
+        sb.AppendLine("        public override string ToString() =>");
+        sb.Append("            $\"");
+        sb.Append(string.Join(", ", headers.Select(h =>
+        {
+            string prop = SanitizeIdentifier(h);
+            return $"{prop}={{{prop}}}";
+        })));
+        sb.AppendLine("\";");
+
+        sb.AppendLine("    }");
+        sb.AppendLine("}");
+
+        return sb.ToString();
+    }
+
+    private static string[] ParseCsvLine(string line)
+    {
+        // Simple CSV parser – handles quoted fields but not escaped quotes inside quotes.
+        var fields = new System.Collections.Generic.List<string>();
+        var current = new StringBuilder();
+        bool inQuotes = false;
+
+        for (int i = 0; i < line.Length; i++)
+        {
+            char c = line[i];
+            if (c == '"')
+            {
+                inQuotes = !inQuotes;
+            }
+            else if (c == ',' && !inQuotes)
+            {
+                fields.Add(current.ToString().Trim());
+                current.Clear();
+            }
+            else
+            {
+                current.Append(c);
+            }
+        }
+        fields.Add(current.ToString().Trim());
+        return fields.ToArray();
+    }
+
+    private static string SanitizeIdentifier(string name)
+    {
+        var sb = new StringBuilder();
+        foreach (char c in name)
+        {
+            if (char.IsLetterOrDigit(c) || c == '_')
+                sb.Append(c);
+        }
+
+        string result = sb.ToString();
+        if (result.Length == 0)
+            return "_";
+
+        // Ensure starts with letter or underscore.
+        if (char.IsDigit(result[0]))
+            result = "_" + result;
+
+        // PascalCase first letter.
+        return char.ToUpperInvariant(result[0]) + result.Substring(1);
+    }
+
+    private static string CamelCase(string name)
+    {
+        if (name.Length == 0)
+            return name;
+        return char.ToLowerInvariant(name[0]) + name.Substring(1);
+    }
+
+    private static string EscapeString(string value) =>
+        $"\"{value.Replace("\\", "\\\\").Replace("\"", "\\\"")}\"";
+}