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Refactor fluent generator API to explicit Method().WithParameter().WithReturnType() chain #18

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Merged
dex3r merged 3 commits into from
Feb 28, 2026
Merged

Refactor fluent generator API to explicit Method().WithParameter().WithReturnType() chain #18

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7e49393
Initial plan
Copilot Feb 28, 2026
c58c636
refactor fluent API to Method().WithParameter().WithReturnType()
Copilot Feb 28, 2026
b88c40b
test: polish mapper-like fluent test naming
Copilot Feb 28, 2026
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43 changes: 39 additions & 4 deletions MattSourceGenHelpers.Abstractions/Generate.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,9 +4,44 @@ public static class Generate
{
public static IGeneratorsFactory CurrentGenerator { get; set; } = new RecordingGeneratorsFactory();

public static IMethodImplementationGenerator MethodImplementation() => CurrentGenerator.CreateImplementation();
public static IMethodImplementationGenerator<TReturnType> MethodImplementation<TReturnType>() => CurrentGenerator.CreateImplementation<TReturnType>();
public static IMethodImplementationGenerator<TArg1, TReturnType> MethodImplementation<TArg1, TReturnType>() => CurrentGenerator.CreateImplementation<TArg1, TReturnType>();
public static IMethodBuilder Method() => new MethodBuilder(CurrentGenerator);
}

public interface IMethodBuilder
{
IMethodBuilder<TArg1> WithParameter<TArg1>();
IMethodImplementationGenerator<TReturnType> WithReturnType<TReturnType>();
}
Comment on lines +7 to +14

Copilot AI Feb 28, 2026

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The Generate.Method().WithReturnType<TReturnType>() (no-parameter) path is part of the new fluent entrypoint, but current tests only exercise the .WithParameter<TArg1>().WithReturnType<TReturnType>() chain. Adding at least one test that uses the parameterless chain (similar to ColorsClassFluent) would help catch regressions in this new API surface.

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public interface IMethodBuilder<TArg1>
{
IMethodImplementationGenerator<TArg1, TReturnType> WithReturnType<TReturnType>();
}

public class MethodBuilder : IMethodBuilder
{
private readonly IGeneratorsFactory _generatorsFactory;

public MethodBuilder(IGeneratorsFactory generatorsFactory)
{
_generatorsFactory = generatorsFactory;
}

public IMethodBuilder<TArg1> WithParameter<TArg1>() => new MethodBuilder<TArg1>(_generatorsFactory);

public IMethodImplementationGenerator<TReturnType> WithReturnType<TReturnType>() => _generatorsFactory.CreateImplementation<TReturnType>();
}

public class MethodBuilder<TArg1> : IMethodBuilder<TArg1>
{
private readonly IGeneratorsFactory _generatorsFactory;

public MethodBuilder(IGeneratorsFactory generatorsFactory)
{
_generatorsFactory = generatorsFactory;
}

public IMethodImplementationGenerator<TArg1, TReturnType> WithReturnType<TReturnType>() => _generatorsFactory.CreateImplementation<TArg1, TReturnType>();
}
Comment on lines +21 to 45

Copilot AI Feb 28, 2026

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MethodBuilder / MethodBuilder<TArg1> are only constructed internally via Generate.Method() and are not referenced elsewhere in the repo. Consider making these concrete builder types internal (and potentially sealed) to avoid expanding the public API surface unnecessarily; consumers can still program against the public IMethodBuilder interfaces returned by Generate.Method().

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public class EmptyGeneratorsFactory : IGeneratorsFactory
Expand Down Expand Up @@ -40,4 +75,4 @@ public interface IGeneratorsFactory
IMethodImplementationGenerator CreateImplementation();
IMethodImplementationGenerator<TReturnType> CreateImplementation<TReturnType>();
IMethodImplementationGenerator<TArg1, TReturnType> CreateImplementation<TArg1, TReturnType>();
}
}
4 changes: 2 additions & 2 deletions MattSourceGenHelpers.Examples/ColorsClassFluent.cs
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Expand Up @@ -9,7 +9,7 @@ public partial class ColorsClassFluent
[GeneratesMethod(nameof(GetAllColorsString))]
static IMethodImplementationGenerator GetAllColorsString_Generator() =>
Generate
.MethodImplementation<string>()
.Method().WithReturnType<string>()
.WithBody(() => string.Join(", ", Enum.GetNames<ColorsEnum>()));
}

Expand All @@ -20,4 +20,4 @@ public string GetAllColorsString()
{
return "Red, Green, Blue";
}
*/
*/
4 changes: 2 additions & 2 deletions MattSourceGenHelpers.Examples/PiExampleFluent.cs
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Expand Up @@ -10,7 +10,7 @@ public static partial class PiExampleFluent
[GeneratesMethod(nameof(GetPiDecimal))]
static IMethodImplementationGenerator GetPiDecimal_Generator_Specialized() =>
Generate
.MethodImplementation<int, int>()
.Method().WithParameter<int>().WithReturnType<int>()
.WithSwitchBody()
.ForCases(0, 1, 2, Integer.Range(300, 303)).ReturnConstantValue(decimalNumber => SlowMath.CalculatePiDecimal(decimalNumber))
.ForDefaultCase().WithBody(decimalNumber => () => SlowMath.CalculatePiDecimal(decimalNumber));
Expand All @@ -32,4 +32,4 @@ public static int GetPiDecimal(int decimalNumber)
default: return CalculatePiDecimal(decimalNumber);
}
}
*/
*/
50 changes: 49 additions & 1 deletion MattSourceGenHelpers.Tests/PiExampleFluentTests.cs
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Expand Up @@ -49,6 +49,40 @@ public static partial int GetPiDecimal(int decimalNumber)

Assert.That(generatedCode, Is.EqualTo(expectedCode));
}

[TestCase(1, "Dog")]
[TestCase(2, "Cat")]
[TestCase(3, "Unknown")]
public void MapperFluentLikeGenerator_ProducesExpectedRuntimeOutput(int source, string expected)
{
string result = TestMapperFluent.MapToMammal(source);

Assert.That(result, Is.EqualTo(expected));
}

[Test]
public void MapperFluentLikeGenerator_ProducesExpectedGeneratedCode()
{
string generatedCode = GeneratedCodeTestHelper.ReadGeneratedCode("TestMapperFluent_MapToMammal.g.cs");
string expectedCode = """
namespace MattSourceGenHelpers.Tests;

static partial class TestMapperFluent
{
public static partial string MapToMammal(int animalCode)
{
switch (animalCode)
{
case 1: return "Dog";
case 2: return "Cat";
default: return "Unknown";
}
}
}
""".ReplaceLineEndings("\n").TrimEnd();

Assert.That(generatedCode, Is.EqualTo(expectedCode));
}
}

public static partial class TestPiFluentClass
Expand All @@ -58,8 +92,22 @@ public static partial class TestPiFluentClass
[GeneratesMethod(nameof(GetPiDecimal))]
static IMethodImplementationGenerator GetPiDecimal_Generator() =>
Generate
.MethodImplementation<int, int>()
.Method().WithParameter<int>().WithReturnType<int>()
.WithSwitchBody()
.ForCases(0, 1, 2, Integer.Range(300, 303)).ReturnConstantValue(decimalNumber => TestSlowMath.CalculatePiDecimal(decimalNumber))
.ForDefaultCase().WithBody(decimalNumber => () => TestSlowMath.CalculatePiDecimal(decimalNumber));
}

public static partial class TestMapperFluent
{
public static partial string MapToMammal(int animalCode);

[GeneratesMethod(nameof(MapToMammal))]
static IMethodImplementationGenerator MapToMammal_Generator() =>
Generate
.Method().WithParameter<int>().WithReturnType<string>()
.WithSwitchBody()
.ForCases(1).ReturnConstantValue(_ => "Dog")
.ForCases(2).ReturnConstantValue(_ => "Cat")
.ForDefaultCase().WithBody(_ => () => "Unknown");
}