Repository F# setup

open System
open System.IO
open System.Threading
open System.Threading.Tasks
open Axial
open Axial.Layers
open Axial.Console
open Axial.FileSystem
open Axial.Hosting
open Axial.Hosting.Browser
open Axial.Hosting.Node
open Axial.HttpClient
open Axial.PlatformService
open Axial.Process
open Axial.State
open Axial.Telemetry
open Axial.Telemetry.JavaScript

Your First Application

Use App.run when a Flow is the root of an application. It carries cancellation from the calling Async and returns after the root scope and its resources have closed.

open Axial

let application : Flow<string> =
    flow {
        return "Hello from Flow"
    }

let run () =
    async {
        let! exit = App.run () application

        match exit with
        | Exit.Success message -> printfn "%s" message
        | Exit.Failure cause -> printfn "%s" (Cause.prettyPrint string cause)
    }

Axial

application: Flow<string>

Flow

A flow that requires no environment and cannot fail with a typed error.

string

An abbreviation for the CLI type . Basic Types

flow: FlowBuilder

The universal flow { } computation expression.

run: unit -> Async<unit>

async: AsyncBuilder

Builds an asynchronous workflow using computation expression syntax. let sleepExample() = async { printfn "sleeping" do! Async.Sleep 10 printfn "waking up" return 6 } sleepExample() |> Async.RunSynchronously

exit: Exit<string,Never>

Axial.App

Starts and controls root Flow applications without requiring an external hosting framework.

run: 'env -> Flow<'env,'error,'value> -> Async<Exit<'value,'error>>

Runs a root workflow to completion using the caller's asynchronous cancellation token. The explicit environment supplied to the root workflow. The root workflow to run. The final exit after the root scope has closed. Fable compatible

Axial.Exit`2

Represents the final outcome of a workflow execution. The type of the success value. The type of the domain-specific failure value.

Success

The workflow completed successfully.

message: string

printfn: Printf.TextWriterFormat<'T> -> 'T

Print to stdout using the given format, and add a newline. The formatter. The formatted result. See Printf.printfn (link: ) for examples.

Failure

The workflow failed due to a specific cause.

cause: Cause<Never>

Axial.Cause

prettyPrint: ('error -> string) -> Cause<'error> -> string

Pretty prints a cause tree for diagnostics.

string: 'T -> string

Converts the argument to a string using ToString. For standard integer and floating point values and any type that implements IFormattable, ToString conversion uses CultureInfo.InvariantCulture. The input value. The converted string. string 'A' // evaluates to "A" string 0xff // evaluates to "255" string -10 // evaluates to "-10"

The `()` value is the environment because this workflow has no dependencies. An application with an `AppEnv` record passes its live value in the same position.

Use App.start when a signal handler, desktop window, UI component, or external host will request shutdown later.

The Application Lifecycle guide covers start and stop ownership. Hosting guides show the .NET, Node, and browser boundaries.

You now have the complete introductory path: describe work, compose it, distinguish outcomes, provide dependencies, and run one root workflow.

Go further

Application Lifecycle covers App.start, coordinated stop, and lifecycle ownership.
Scopes and Resources explains finalizers and acquisition/release safety.
Hosting connects the root application to .NET, Node, or browser hosts.

Your First Application

Go further

Overview

Docs

API Reference