REslava.ResultFlow 1.47.1

REslava.ResultFlow

Library-agnostic source generator for automatic Mermaid pipeline diagrams — works with any fluent Result library.

Add [ResultFlow] to any fluent method → the diagram is injected as a comment by the IDE code action (no build needed), or accessed as a const string after build. Zero runtime overhead. Zero manual maintenance.

Ships with a built-in convention dictionary pre-configured for REslava.Result, ErrorOr, LanguageExt, and FluentResults. Any other library can be supported by adding a resultflow.json file to your project.

Using REslava.Result? Consider REslava.Result.Flow for richer diagrams with typed error edges and full semantic analysis.

Installation

dotnet add package REslava.ResultFlow

No extra using required — the [ResultFlow] attribute is injected into your compilation automatically by the source generator.

Quick Start

[ResultFlow]
public async Task<Result<UserDto>> RegisterAsync(RegisterCommand cmd) =>
    await CreateUser(cmd)
        .EnsureAsync(IsEmailValid, new InvalidEmailError())
        .BindAsync(SaveUser)
        .TapAsync(SendWelcomeEmail)
        .MapAsync(ToDto);

Use the IDE code action to inject the diagram as a comment directly above the method — no build required:

/*
```mermaid
flowchart LR
    N0_EnsureAsync["EnsureAsync"]:::gatekeeper
    ...
```*/
[ResultFlow]
public async Task<Result<UserDto>> RegisterAsync(RegisterCommand cmd) => ...

Or access the generated constant after build and paste it into any Mermaid renderer:

string diagram = Generated.ResultFlow.UserService_Flows.RegisterAsync;
// Paste into mermaid.live, GitHub, Notion, VS Code, or your wiki

Generated Diagram Example

flowchart LR
    N0_EnsureAsync["EnsureAsync"]:::gatekeeper
    N0_EnsureAsync -->|pass| N1_BindAsync
    N0_EnsureAsync -->|fail| F0["Failure"]:::failure
    N1_BindAsync["BindAsync"]:::transform
    N1_BindAsync -->|ok| N2_TapAsync
    N1_BindAsync -->|fail| F1["Failure"]:::failure
    N2_TapAsync["TapAsync"]:::sideeffect
    N2_TapAsync --> N3_MapAsync
    N3_MapAsync["MapAsync"]:::transform
    classDef gatekeeper fill:#e3e9fa,color:#3f5c9a
    classDef transform fill:#e3f0e8,color:#2f7a5c
    classDef sideeffect fill:#fff4d9,color:#b8882c
    classDef failure fill:#f8e3e3,color:#b13e3e

Each operation is color-coded by semantic role:

• Lavender — gatekeepers (Ensure) — can fail validation
• Mint — transforms (Bind / Map) — shape the result
• Vanilla — side effects (Tap) — fire-and-forget
• Soft pink — failure paths

Supported Libraries

The built-in convention dictionary covers the most popular Result libraries out of the box — no configuration needed:

Any unrecognized method is rendered as a generic operation node — the diagram is still generated.

Custom Method Classification — resultflow.json

Add a resultflow.json file to your project to classify custom or third-party methods. Config entries override the built-in dictionary.

{
  "mappings": [
    {
      "bind":       ["Chain", "AndThen"],
      "map":        ["Transform"],
      "tap":        ["Log", "Audit"],
      "gatekeeper": ["Require"],
      "terminal":   ["Fold"]
    }
  ]
}

Register it as an AdditionalFile in your .csproj:

<ItemGroup>
  <AdditionalFiles Include="resultflow.json" />
</ItemGroup>

Supported keys: bind, map, tap, tapOnFailure, gatekeeper, terminal.

Code Action

The companion analyzer detects [ResultFlow] methods that are missing the diagram as a developer comment. A single-click code fix inserts the generated Mermaid diagram directly above the method body — so the diagram lives next to the code that produced it.

Diagnostics

Documentation

Full documentation: reslava.github.io/nuget-package-reslava-result

MIT License | Works with any .NET project (netstandard2.0)