feature: Ability to specify default field modifier, closes #31

src/Avalonia.NameGenerator/AvaloniaNameSourceGenerator.cs

@@ -17,26 +17,10 @@ namespace Avalonia.NameGenerator
 
         public void Execute(GeneratorExecutionContext context)
         {
-            var compilation = (CSharpCompilation)context.Compilation;
+            var generator = CreateNameGenerator(context);
-            var types = new RoslynTypeSystem(compilation);
-            var compiler = MiniCompiler.CreateDefault(types, MiniCompiler.AvaloniaXmlnsDefinitionAttribute);
-
-            var options = new GeneratorOptions(context);
-            ICodeGenerator generator = options.AvaloniaNameGeneratorBehavior switch {
-                Behavior.OnlyProperties => new OnlyPropertiesCodeGenerator(),
-                Behavior.InitializeComponent => new InitializeComponentCodeGenerator(),
-                _ => throw new ArgumentOutOfRangeException()
-            };
-
-            INameGenerator avaloniaNameGenerator =
-                new AvaloniaNameGenerator(
-                    new XamlXViewResolver(types, compiler, true, type => ReportInvalidType(context, type)),
-                    new XamlXNameResolver(),
-                    generator);
-
             try
             {
-                var partials = avaloniaNameGenerator.GenerateNameReferences(context.AdditionalFiles);
+                var partials = generator.GenerateNameReferences(context.AdditionalFiles);
                 foreach (var partial in partials) context.AddSource(partial.FileName, partial.Content);
             }
             catch (Exception exception)
@@ -45,10 +29,29 @@ namespace Avalonia.NameGenerator
             }
         }
 
+        private static INameGenerator CreateNameGenerator(GeneratorExecutionContext context)
+        {
+            var options = new GeneratorOptions(context);
+            var defaultFieldModifier = options.AvaloniaNameGeneratorDefaultFieldModifier.ToString().ToLowerInvariant();
+            ICodeGenerator generator = options.AvaloniaNameGeneratorBehavior switch {
+                Behavior.OnlyProperties => new OnlyPropertiesCodeGenerator(),
+                Behavior.InitializeComponent => new InitializeComponentCodeGenerator(),
+                _ => throw new ArgumentOutOfRangeException()
+            };
+
+            var types = new RoslynTypeSystem((CSharpCompilation)context.Compilation);
+            var compiler = MiniCompiler.CreateDefault(types, MiniCompiler.AvaloniaXmlnsDefinitionAttribute);
+            return new AvaloniaNameGenerator(
+                new XamlXViewResolver(types, compiler, true, type => ReportInvalidType(context, type)),
+                new XamlXNameResolver(defaultFieldModifier),
+                generator);
+        }
+
         private static void ReportUnhandledError(GeneratorExecutionContext context, Exception error)
         {
-            const string message = "Unhandled exception occured while generating typed Name references. " +
+            const string message =
-                                   "Please file an issue: https://github.com/avaloniaui/avalonia.namegenerator";
+                "Unhandled exception occured while generating typed Name references. " +
+                "Please file an issue: https://github.com/avaloniaui/avalonia.namegenerator";
             context.ReportDiagnostic(
                 Diagnostic.Create(
                     new DiagnosticDescriptor(
@@ -63,8 +66,9 @@ namespace Avalonia.NameGenerator
 
         private static void ReportInvalidType(GeneratorExecutionContext context, string typeName)
         {
-            var message = $"Avalonia x:Name generator was unable to generate names for type '{typeName}'. " +
+            var message =
-                          $"The type '{typeName}' does not exist in the assembly.";
+                $"Avalonia x:Name generator was unable to generate names for type '{typeName}'. " +
+                $"The type '{typeName}' does not exist in the assembly.";
             context.ReportDiagnostic(
                 Diagnostic.Create(
                     new DiagnosticDescriptor(

src/Avalonia.NameGenerator/Generator.props

@@ -1,10 +1,12 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <AvaloniaNameGeneratorBehavior Condition="'$(AvaloniaNameGeneratorBehavior)' == ''">OnlyProperties</AvaloniaNameGeneratorBehavior>
+    <AvaloniaNameGeneratorDefaultFieldModifier Condition="'$(AvaloniaNameGeneratorDefaultFieldModifier)' == ''">internal</AvaloniaNameGeneratorDefaultFieldModifier>
   </PropertyGroup>
   <ItemGroup>
     <CompilerVisibleItemMetadata Include="AdditionalFiles" MetadataName="SourceItemGroup"/>
     <CompilerVisibleProperty Include="AvaloniaNameGeneratorBehavior" />
+    <CompilerVisibleProperty Include="AvaloniaNameGeneratorDefaultFieldModifier" />
   </ItemGroup>
   <Target Name="_InjectAdditionalFiles" BeforeTargets="GenerateMSBuildEditorConfigFileShouldRun">
     <ItemGroup>

src/Avalonia.NameGenerator/Generator/XamlXNameResolver.cs

@@ -9,6 +9,12 @@ namespace Avalonia.NameGenerator.Generator
     internal class XamlXNameResolver : INameResolver, IXamlAstVisitor
     {
         private readonly List<ResolvedName> _items = new();
+        private readonly string _defaultFieldModifier;
+
+        public XamlXNameResolver(string defaultFieldModifier = "internal")
+        {
+            _defaultFieldModifier = defaultFieldModifier;
+        }
 
         public IReadOnlyList<ResolvedName> ResolveNames(XamlDocument xaml)
         {
@@ -55,7 +61,7 @@ namespace Avalonia.NameGenerator.Generator
 
         void IXamlAstVisitor.Pop() { }
 
-        private static string TryGetFieldModifier(XamlAstObjectNode objectNode)
+        private string TryGetFieldModifier(XamlAstObjectNode objectNode)
         {
             // We follow Xamarin.Forms API behavior in terms of x:FieldModifier here:
             // https://docs.microsoft.com/en-us/xamarin/xamarin-forms/xaml/field-modifiers
@@ -78,7 +84,7 @@ namespace Avalonia.NameGenerator.Generator
                 "protected" => "protected",
                 "internal" => "internal",
                 "notpublic" => "internal",
-                _ => "internal"
+                _ => _defaultFieldModifier
             };
         }
     }

src/Avalonia.NameGenerator/GeneratorOptions.cs

@@ -5,7 +5,16 @@ namespace Avalonia.NameGenerator
 {
     public enum BuildProperties
     {
-        AvaloniaNameGeneratorBehavior = 0
+        AvaloniaNameGeneratorBehavior = 0,
+        AvaloniaNameGeneratorDefaultFieldModifier = 1,
+    }
+
+    public enum DefaultFieldModifier
+    {
+        Public = 0,
+        Private = 1,
+        Internal = 2,
+        Protected = 3,
     }
 
     public enum Behavior
@@ -29,10 +38,25 @@ namespace Avalonia.NameGenerator
                         nameof(BuildProperties.AvaloniaNameGeneratorBehavior),
                         nameof(Behavior.OnlyProperties));
 
-                if (!Enum.TryParse(propertyValue, out Behavior behavior))
+                if (!Enum.TryParse(propertyValue, true, out Behavior behavior))
                     return Behavior.OnlyProperties;
                 return behavior;
             }
         }
+
+        public DefaultFieldModifier AvaloniaNameGeneratorDefaultFieldModifier
+        {
+            get
+            {
+                var propertyValue = _context
+                    .GetMSBuildProperty(
+                        nameof(BuildProperties.AvaloniaNameGeneratorDefaultFieldModifier),
+                        nameof(DefaultFieldModifier.Internal));
+
+                if (!Enum.TryParse(propertyValue, true, out DefaultFieldModifier modifier))
+                    return DefaultFieldModifier.Internal;
+                return modifier;
+            }
+        }
     }
 }