Getting Started

Mon, 01 Jan 0001 00:00:00 +0000

Getting Started

FsFlow is a toolkit for building robust, Result-based programs in F#. It allows you to scale from simple validation logic to complex, effectful application boundaries using a single, unified mental model.

1. The Continuum of Logic

FsFlow is designed around a continuum. You should always use the simplest tool that satisfies your current requirement:

Pure Checks -> Result & Validation -> Flow

Pure Checks: Reusable predicates for basic validation.
Result & Validation: Domain logic that handles success or failure (either fail-fast or error-accumulating).
Flow: The application boundary where you need dependencies, async/task interop, logging, or cancellation.

2. Start with Checks and Results

Most logic starts pure. Use Check for reusable predicates and Result for domain logic.

Straightforward Examples

Mon, 01 Jan 0001 00:00:00 +0000

Straightforward Examples

These examples show how to use FsFlow for common tasks without the overhead of a full application setup.

1. Simple Environment Access

Use Flow.read to project a single field from your environment record.

type Config = { ApiUrl: string }

let getUrl =
    flow {
        let! url = Flow.read _.ApiUrl
        return url
    }

let outcome = getUrl |> Flow.run { ApiUrl = "https://api.example.com" }
// outcome = Exit.Success "https://api.example.com"

2. Combining Pure Logic and Async Work

Use flow {} to mix pure Check logic, Async blocks, and other flows.

let validateId id =
    id |> okIf (id > 0) |> orError "Invalid ID"

let fetchUser id =
    async { return { Id = id; Name = "Ada" } }

let workflow id =
    flow {
        let! validId = validateId id
        let! user = fetchUser validId // Binds Async<'T> directly
        return user.Name
    }

let effect = workflow 42 |> Flow.run ()
// effect = Effect<string, string> (ValueTask or Async)

3. Retrying a Flow

Use the Schedule module to add operational policies like retries.

Start on FsFlow

Getting Started

Getting Started

1. The Continuum of Logic

2. Start with Checks and Results

Straightforward Examples

Straightforward Examples

1. Simple Environment Access

2. Combining Pure Logic and Async Work

3. Retrying a Flow