added missing Append extensions

README.md

@@ -4,6 +4,108 @@ This library uses features of C# to achieve railway-oriented programming.
 
 The desire is to make somewhat user-friendly experience while using result-object pattern.
 
-## Contents
+## Features
 
-_Coming soon..._
+- Immutable ```Error``` class
+- ```Result``` object
+- A bunch of extensions to use result-object pattern with
+- ```Try``` extensions to wrap function calls with result-object
+- ```Ensure``` extensions to utilize result-object in validation scenarios
+
+## Getting Started
+
+### Install from local Gitea package repository
+
+```sh
+# Setup NuGet registry from the command line
+dotnet nuget add source --name gitea_jstdev https://gitea.jstdev.ru/api/packages/just/nuget/index.json
+# then install the package using NuGet
+dotnet add package --source gitea_jstdev Just.Railway
+```
+
+## Examples
+
+### Error
+
+```csharp
+using Just.Railway;
+Error expectedError = Error.New(type: "Some Error", message: "Some error detail");
+Error exceptionalError = Error.New(new Exception("Some Exception"));
+Error manyErrors = Error.Many(expectedError, exceptionalError);
+// the same result while using .Append(..) or +
+manyErrors = expectedError.Append(exceptionalError);
+manyErrors = expectedError + exceptionalError;
+```
+
+> **Note**
+> You can easily serialize/deserialize Error to and from JSON
+
+### Result
+
+#### As return value:
+
+```csharp
+Result Foo()
+{
+    // ...
+    if (SomeCondition())
+        return Result.Failure(Error.New("Some Error"));
+        // or just: return Error.New("Some Error");
+    // ...
+    return Result.Success();
+}
+
+Result<T> Bar()
+{
+    T value;
+    // ...
+    if (SomeCondition())
+        return Error.New("Some Error");
+    // ...
+    return value;
+}
+```
+
+#### Consume Result object
+
+```csharp
+Result<int> result = GetResult();
+
+var value = result
+    .Append("new")
+    .Map((i, s) => $"{s} result {i}")
+    .Match(
+        onSuccess: x => x,
+        onFailure: err => err.ToString()
+    );
+// value: "new result 1"
+
+Result<int> GetResult() => Result.Success(1);
+```
+
+### Try
+
+```csharp
+Result result = Try.Run(SomeAction);
+// you can pass up to 5 arguments like this
+result = Try.Run(SomeActionWithArguments, 1, 2.0, "3");
+
+// you also can call functions
+Result<int> resultWithValue = Try.Run(SomeFunction);
+
+void SomeAction() {}
+void SomeActionWithArguments(int a1, double a2, string? a3) {}
+int SomeFunction() => 1;
+```
+
+### Ensure
+
+```csharp
+var value = GetValue();
+Result<int> result = Ensure.That(value)
+    .NotNull()
+    .Satisfies(i => i < 100)
+    .Result();
+
+int? GetValue() => 1;
+```

Railway.SourceGenerator/EnsureExtensionsExecutor.cs

@@ -7,7 +7,7 @@ using Microsoft.CodeAnalysis;
 
 namespace Just.Railway.SourceGen;
 
-public sealed class EnsureExtensionExecutor : IGeneratorExecutor
+public sealed class EnsureExtensionsExecutor : IGeneratorExecutor
 {
     public void Execute(SourceProductionContext context, Compilation source)
     {
@@ -80,7 +80,7 @@ public sealed class EnsureExtensionExecutor : IGeneratorExecutor
 
         typeOverloads.ForEach(def => sb.AppendLine($$"""
         [PureAttribute]
-        [GeneratedCodeAttribute("{{nameof(EnsureExtensionExecutor)}}", "1.0.0.0")]
+        [GeneratedCodeAttribute("{{nameof(EnsureExtensionsExecutor)}}", "1.0.0.0")]
         public static Ensure<{{def.CollectionType}}> NotEmpty{{def.TemplateDef}}(this in Ensure<{{def.CollectionType}}> ensure, {{errorParameterDecl}})
         {
             return ensure.State switch
@@ -101,7 +101,7 @@ public sealed class EnsureExtensionExecutor : IGeneratorExecutor
 
         sb.AppendLine($$"""
         [PureAttribute]
-        [GeneratedCodeAttribute("{{nameof(EnsureExtensionExecutor)}}", "1.0.0.0")]
+        [GeneratedCodeAttribute("{{nameof(EnsureExtensionsExecutor)}}", "1.0.0.0")]
         public static Ensure<T> NotNull<T>(this in Ensure<T?> ensure, {{errorParameterDecl}})
             where T : struct
         {
@@ -117,7 +117,7 @@ public sealed class EnsureExtensionExecutor : IGeneratorExecutor
         """);
         sb.AppendLine($$"""
         [PureAttribute]
-        [GeneratedCodeAttribute("{{nameof(EnsureExtensionExecutor)}}", "1.0.0.0")]
+        [GeneratedCodeAttribute("{{nameof(EnsureExtensionsExecutor)}}", "1.0.0.0")]
         public static Ensure<T> NotNull<T>(this in Ensure<T?> ensure, {{errorParameterDecl}})
             where T : notnull
         {
@@ -138,7 +138,7 @@ public sealed class EnsureExtensionExecutor : IGeneratorExecutor
         string defaultErrorExpr = "?? Error.New(DefaultErrorType, $\"Value {{{ensure.ValueExpression}}} does not satisfy the requirement.\")";
         sb.AppendLine($$"""
         [PureAttribute]
-        [GeneratedCodeAttribute("{{nameof(EnsureExtensionExecutor)}}", "1.0.0.0")]
+        [GeneratedCodeAttribute("{{nameof(EnsureExtensionsExecutor)}}", "1.0.0.0")]
         public static Ensure<T> Satisfies<T>(this in Ensure<T> ensure, Func<T, bool> requirement, {{errorParameterDecl}})
         {
             return ensure.State switch
@@ -160,7 +160,7 @@ public sealed class EnsureExtensionExecutor : IGeneratorExecutor
     {
         sb.AppendLine($$"""
         [PureAttribute]
-        [GeneratedCodeAttribute("{{nameof(EnsureExtensionExecutor)}}", "1.0.0.0")]
+        [GeneratedCodeAttribute("{{nameof(EnsureExtensionsExecutor)}}", "1.0.0.0")]
         public static async {{taskType}}<Ensure<T>> Satisfies<T>(this {{taskType}}<Ensure<T>> ensureTask, Func<T, bool> requirement, {{errorParameterDecl}})
         {
             var ensure = await ensureTask.ConfigureAwait(false);
@@ -176,7 +176,7 @@ public sealed class EnsureExtensionExecutor : IGeneratorExecutor
         """);
         sb.AppendLine($$"""
         [PureAttribute]
-        [GeneratedCodeAttribute("{{nameof(EnsureExtensionExecutor)}}", "1.0.0.0")]
+        [GeneratedCodeAttribute("{{nameof(EnsureExtensionsExecutor)}}", "1.0.0.0")]
         public static async {{taskType}}<Ensure<T>> Satisfies<T>(this Ensure<T> ensure, Func<T, {{taskType}}<bool>> requirement, {{errorParameterDecl}})
         {
             return ensure.State switch
@@ -191,7 +191,7 @@ public sealed class EnsureExtensionExecutor : IGeneratorExecutor
         """);
         sb.AppendLine($$"""
         [PureAttribute]
-        [GeneratedCodeAttribute("{{nameof(EnsureExtensionExecutor)}}", "1.0.0.0")]
+        [GeneratedCodeAttribute("{{nameof(EnsureExtensionsExecutor)}}", "1.0.0.0")]
         public static async {{taskType}}<Ensure<T>> Satisfies<T>(this {{taskType}}<Ensure<T>> ensureTask, Func<T, {{taskType}}<bool>> requirement, {{errorParameterDecl}})
         {
             var ensure = await ensureTask.ConfigureAwait(false);

Railway.SourceGenerator/ExtensionsMethodGenerator.cs

@@ -19,7 +19,7 @@ public class ExtensionsMethodGenerator : IIncrementalGenerator
         new ResultTapExecutor(),
         new ResultAppendExecutor(),
         new TryExtensionsExecutor(),
-        new EnsureExtensionExecutor(),
+        new EnsureExtensionsExecutor(),
     };
 
     public void Initialize(IncrementalGeneratorInitializationContext context)

Railway.SourceGenerator/ResultAppendExecutor.cs

@@ -200,6 +200,48 @@ internal sealed class ResultAppendExecutor : ResultExtensionsExecutor
         string resultExpandedTypeDef = GenerateResultTypeDef(expandedTemplateArgNames);
         string methodExpandedTemplateDecl = GenerateTemplateDecl(expandedTemplateArgNames);
 
+        sb.AppendLine($$"""
+        [PureAttribute]
+        [GeneratedCodeAttribute("{{nameof(ResultAppendExecutor)}}", "1.0.0.0")]
+        public static async {{taskType}}<{{resultExpandedTypeDef}}> Append{{methodExpandedTemplateDecl}}(this {{taskType}}<{{resultTypeDef}}> resultTask, TNext next)
+        {
+            var result = await resultTask.ConfigureAwait(false);
+            return result.State switch
+            {
+                ResultState.Success => Result.Success({{JoinArguments(resultValueExpansion, "next")}}),
+                ResultState.Error => result.Error!,
+                _ => throw new ResultNotInitializedException(nameof(result))
+            };
+        }
+        """);
+
+        sb.AppendLine($$"""
+        [PureAttribute]
+        [GeneratedCodeAttribute("{{nameof(ResultAppendExecutor)}}", "1.0.0.0")]
+        public static async {{taskType}}<{{resultExpandedTypeDef}}> Append{{methodExpandedTemplateDecl}}(this {{taskType}}<{{resultTypeDef}}> resultTask, Result<TNext> next)
+        {
+            var result = await resultTask.ConfigureAwait(false);
+            if ((result.State & next.State) == ResultState.Bottom)
+            {
+                throw new ResultNotInitializedException(string.Join(';', GetBottom(result.State, next.State)));
+            }
+
+            Error? error = null;
+            if (result.IsFailure)
+            {
+                error += result.Error;
+            }
+            if (next.IsFailure)
+            {
+                error += next.Error;
+            }
+
+            return error is null
+                ? Result.Success({{JoinArguments(resultValueExpansion, "next.Value")}})
+                : error;
+        }
+        """);
+
         sb.AppendLine($$"""
         [PureAttribute]
         [GeneratedCodeAttribute("{{nameof(ResultAppendExecutor)}}", "1.0.0.0")]

Railway/Error.cs

@@ -1,4 +1,5 @@
 using System.Collections;
+using System.Collections.Immutable;
 using System.Runtime.Serialization;
 using System.Text;
 
@@ -10,8 +11,6 @@ namespace Just.Railway;
 [JsonDerivedType(typeof(ManyErrors))]
 public abstract class Error : IEquatable<Error>, IComparable<Error>
 {
-    private IDictionary<string, object>? _extensionData;
-
     protected internal Error(){}
 
     /// <summary>
@@ -77,28 +76,8 @@ public abstract class Error : IEquatable<Error>, IComparable<Error>
 
     [Pure] public abstract string Type { get; }
     [Pure] public abstract string Message { get; }
-    [Pure, JsonExtensionData] public IDictionary<string, object> ExtensionData
-    {
-        get => _extensionData ??= new Dictionary<string, object>();
-        init => _extensionData = value ?? new Dictionary<string, object>();
-    }
-    [Pure] public object? this[string name]
-    {
-        get => _extensionData?.TryGetValue(name, out var val) == true ? val : null;
-
-        set
-        {
-            if (value is null)
-            {
-                _extensionData?.Remove(name);
-            }
-            else
-            {
-                _extensionData ??= new Dictionary<string, object>();
-                _extensionData[name] = value;
-            }
-        }
-    }
+    [Pure, JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)] public ImmutableDictionary<string, string>? ExtensionData { get; init; }
+    [Pure] public string? this[string key] => ExtensionData?.TryGetValue(key, out var value) == true ? value : null;
 
     [Pure, JsonIgnore] public abstract int Count { get; }
     [Pure, JsonIgnore] public abstract bool IsEmpty { get; }
@@ -199,13 +178,13 @@ public sealed class ExceptionalError : Error
         : this(exception.GetType().Name, exception.Message)
     {
         Exception = exception;
-        FillExtensionData(exception);
+        ExtensionData = ExtractExtensionData(exception);
     }
     internal ExceptionalError(string message, Exception exception)
         : this(exception.GetType().Name, message)
     {
         Exception = exception;
-        FillExtensionData(exception);
+        ExtensionData = ExtractExtensionData(exception);
     }
 
     [JsonConstructor]
@@ -231,15 +210,28 @@ public sealed class ExceptionalError : Error
         yield return this;
     }
 
-    private void FillExtensionData(Exception exception)
+    private static ImmutableDictionary<string, string>? ExtractExtensionData(Exception exception)
     {
+        if (!(exception.Data?.Count > 0))
+        return null;
+
+        List<KeyValuePair<string, string>>? values = null;
+
         foreach (var key in exception.Data.Keys)
         {
+            if (key is null) continue;
+
             var value = exception.Data[key];
-            if (key is null || value is null)
-                continue;
-            this.ExtensionData[key.ToString() ?? string.Empty] = value;
+            if (value is null) continue;
+
+            var keyString = key.ToString();
+            var valueString = value.ToString();
+            if (string.IsNullOrEmpty(keyString) || string.IsNullOrEmpty(valueString)) continue;
+
+            values ??= [];
+            values.Add(new(keyString, valueString));
         }
+        return values?.ToImmutableDictionary();
     }
 }
 

Raliway.Tests/Errors/Serialization.cs

@@ -1,3 +1,5 @@
+using System.Collections.Immutable;
+
 namespace Railway.Tests.Errors;
 
 public class Serialization
@@ -8,9 +10,8 @@ public class Serialization
         // Given
         Error many_errors = new ManyErrors(new Error[]{
             new ExpectedError("err1", "msg1"){
-                ExtensionData = {
-                    ["ext"] = "ext_value"
-                }
+                ExtensionData = ImmutableDictionary<string, string>.Empty
+                    .Add("ext", "ext_value"),
             },
             new ExceptionalError(new Exception("msg2")),
         });
@@ -18,7 +19,7 @@ public class Serialization
         var result = JsonSerializer.Serialize(many_errors);
         // Then
         Assert.Equal(
-            expected: "[{\"$$err\":0,\"Type\":\"err1\",\"Message\":\"msg1\",\"ext\":\"ext_value\"},{\"$$err\":1,\"Type\":\"Exception\",\"Message\":\"msg2\"}]",
+            expected: "[{\"$$err\":0,\"Type\":\"err1\",\"Message\":\"msg1\",\"ExtensionData\":{\"ext\":\"ext_value\"}},{\"$$err\":1,\"Type\":\"Exception\",\"Message\":\"msg2\"}]",
             result);
     }
 
@@ -26,7 +27,7 @@ public class Serialization
     public void WhenDeserializingManyErrors()
     {
         // Given
-        var json = "[{\"$$err\":0,\"Type\":\"err1\",\"Message\":\"msg1\",\"ext\":\"ext_value\"},{\"$$err\":1,\"Type\":\"Exception\",\"Message\":\"msg2\"}]";
+        var json = "[{\"$$err\":0,\"Type\":\"err1\",\"Message\":\"msg1\",\"ExtensionData\":{\"ext1\":\"ext_value1\",\"ext2\":\"ext_value2\"}},{\"$$err\":1,\"Type\":\"Exception\",\"Message\":\"msg2\"}]";
         // When
         var result = JsonSerializer.Deserialize<Error[]>(json);
         // Then
@@ -39,7 +40,10 @@ public class Serialization
             result
         );
         Assert.Equal(
-            expected: "ext_value",
-            result[0].ExtensionData["ext"].ToString());
+            expected: "ext_value1",
+            result[0]["ext1"]);
+        Assert.Equal(
+            expected: "ext_value2",
+            result[0]["ext2"]);
     }
 }

Raliway.Tests/Results/Combine.cs

@@ -0,0 +1,78 @@
+namespace Raliway.Tests.Results;
+
+public class Combine
+{
+    [Fact]
+    public void TwoResultCombination_WhenThereIsAnError()
+    {
+        // Given
+        var result1 = Result.Success(1);
+        var result2 = Result.Failure(Error.New("some error"));
+        // When
+        var result = Result.Combine(result1, result2);
+        // Then
+        Assert.True(result.IsFailure);
+        Assert.Equal(result2.Error, result.Error);
+    }
+    [Fact]
+    public void TwoResultCombination_WhenThereAreTwoErrors()
+    {
+        // Given
+        var result1 = Result.Failure<byte>(Error.New("1"));
+        var result2 = Result.Failure(Error.New("2"));
+        // When
+        var result = Result.Combine(result1, result2);
+        // Then
+        Assert.True(result.IsFailure);
+        Assert.Equal(result1.Error + result2.Error, result.Error);
+    }
+    [Fact]
+    public void TwoResultCombination_WhenThereIsNoError()
+    {
+        // Given
+        var result1 = Result.Success(1);
+        var result2 = Result.Success(3.14);
+        // When
+        var result = Result.Combine(result1, result2);
+        // Then
+        Assert.True(result.IsSuccess);
+    }
+    [Fact]
+    public void ThreeResultCombination_WhenThereIsAnError()
+    {
+        // Given
+        var result1 = Result.Success(1);
+        var result2 = Result.Success(3.14);
+        var result3 = Result.Failure(Error.New("some error"));
+        // When
+        Result<(int, double)> result = Result.Combine(result1, result2, result3);
+        // Then
+        Assert.True(result.IsFailure);
+        Assert.Equal(result3.Error, result.Error);
+    }
+    [Fact]
+    public void ThreeResultCombination_WhenThereAreTwoErrors()
+    {
+        // Given
+        var result1 = Result.Failure<int?>(Error.New("1"));
+        var result2 = Result.Success(3.14);
+        var result3 = Result.Failure(Error.New("3"));
+        // When
+        Result<(int?, double)> result = Result.Combine(result1, result2, result3);
+        // Then
+        Assert.True(result.IsFailure);
+        Assert.Equal(result1.Error + result3.Error, result.Error);
+    }
+    [Fact]
+    public void ThreeResultCombination_WhenThereIsNoError()
+    {
+        // Given
+        var result1 = Result.Success(1);
+        var result2 = Result.Success(3.14);
+        var result3 = Result.Success();
+        // When
+        var result = Result.Combine(result1, result2, result3);
+        // Then
+        Assert.True(result.IsSuccess);
+    }
+}

Raliway.Tests/Results/GeneralUsage.cs

@@ -2,80 +2,6 @@ namespace Raliway.Tests.Results;
 
 public class GeneralUsage
 {
-    [Fact]
-    public void TwoResultCombination_WhenThereIsAnError()
-    {
-        // Given
-        var result1 = Result.Success(1);
-        var result2 = Result.Failure(Error.New("some error"));
-        // When
-        var result = Result.Combine(result1, result2);
-        // Then
-        Assert.True(result.IsFailure);
-        Assert.Equal(result2.Error, result.Error);
-    }
-    [Fact]
-    public void TwoResultCombination_WhenThereAreTwoErrors()
-    {
-        // Given
-        var result1 = Result.Failure<byte>(Error.New("1"));
-        var result2 = Result.Failure(Error.New("2"));
-        // When
-        var result = Result.Combine(result1, result2);
-        // Then
-        Assert.True(result.IsFailure);
-        Assert.Equal(result1.Error + result2.Error, result.Error);
-    }
-    [Fact]
-    public void TwoResultCombination_WhenThereIsNoError()
-    {
-        // Given
-        var result1 = Result.Success(1);
-        var result2 = Result.Success(3.14);
-        // When
-        var result = Result.Combine(result1, result2);
-        // Then
-        Assert.True(result.IsSuccess);
-    }
-    [Fact]
-    public void ThreeResultCombination_WhenThereIsAnError()
-    {
-        // Given
-        var result1 = Result.Success(1);
-        var result2 = Result.Success(3.14);
-        var result3 = Result.Failure(Error.New("some error"));
-        // When
-        Result<(int, double)> result = Result.Combine(result1, result2, result3);
-        // Then
-        Assert.True(result.IsFailure);
-        Assert.Equal(result3.Error, result.Error);
-    }
-    [Fact]
-    public void ThreeResultCombination_WhenThereAreTwoErrors()
-    {
-        // Given
-        var result1 = Result.Failure<int?>(Error.New("1"));
-        var result2 = Result.Success(3.14);
-        var result3 = Result.Failure(Error.New("3"));
-        // When
-        Result<(int?, double)> result = Result.Combine(result1, result2, result3);
-        // Then
-        Assert.True(result.IsFailure);
-        Assert.Equal(result1.Error + result3.Error, result.Error);
-    }
-    [Fact]
-    public void ThreeResultCombination_WhenThereIsNoError()
-    {
-        // Given
-        var result1 = Result.Success(1);
-        var result2 = Result.Success(3.14);
-        var result3 = Result.Success();
-        // When
-        var result = Result.Combine(result1, result2, result3);
-        // Then
-        Assert.True(result.IsSuccess);
-    }
-
     [Fact]
     public void ChainedResultExtensions_WhenThereIsNoError()
     {
@@ -104,10 +30,9 @@ public class GeneralUsage
     public void ChainedResultExtensions_WhenThereIsAnError()
     {
         // Given
-        
-        // When
         var error = Error.New("test");
         
+        // When
 
         var result = Result.Success()
             .Append(() => Result.Failure<int>(error))
@@ -115,7 +40,7 @@ public class GeneralUsage
             .Map((i, s) =>
             {
                 Assert.Fail();
-                return Result.Success("");
+                return "";
             })
             .Append("some")
             .Bind((s1, s2) => 
@@ -139,4 +64,68 @@ public class GeneralUsage
         // Then
         Assert.Equal("satisfied", result);
     }
+
+    [Fact]
+    public async Task ChainedResultAsyncExtensions_WhenThereIsNoError()
+    {
+        // Given
+
+        // When
+        var result = await Result.Success()
+            .Append(() => ValueTask.FromResult(Result.Success(1)))
+            .Append("test")
+            .Map((i, s) => $"{s}_{i}")
+            .Append("some")
+            .Bind(async (s1, s2) => await ValueTask.FromResult(Result.Success(string.Join(';', s1, s2))))
+            .Match(
+                onSuccess: s => s.ToUpper(),
+                onFailure: _ =>
+                {
+                    Assert.Fail();
+                    return "";
+                }
+            );
+        
+        Assert.Equal("TEST_1;SOME", result);
+    }
+
+    [Fact]
+    public async Task ChainedResultAsyncExtensions_WhenThereIsAnError()
+    {
+        // Given
+        var error = Error.New("test");
+        
+        // When
+
+        var result = await Result.Success()
+            .Append(() => Task.FromResult(Result.Failure<int>(error)))
+            .Append("test")
+            .Map((i, s) =>
+            {
+                Assert.Fail();
+                return "";
+            })
+            .Append("some")
+            .Bind(async (s1, s2) => 
+            {
+                Assert.Fail();
+                await Task.CompletedTask;
+                return Result.Success("");
+            })
+            .Match(
+                onSuccess: _ => 
+                {
+                    Assert.Fail();
+                    return "";
+                },
+                onFailure: err =>
+                {
+                    Assert.Equal(error, err);
+                    return "satisfied";
+                }
+            );
+
+        // Then
+        Assert.Equal("satisfied", result);
+    }
 }