kspeakman

namespace Utilities

(*
    UMP (Update Model Perform) is a reformulation of MVU (Model View Update).
    Here are the differences:
    * `Cmd<Msg>` is replaced by a user-defined `Effect` (list) and a `perform` function
      - allows testing that the correct side effects were chosen, using simple value equality (`=`)
      - `Effect` is a DU, each case represents a side effect and its required data
      - `perform` executes the `Effect`, returns a `Msg`
      - without Cmd, all types are user-defined, so UMP code doesn't depend on UMP lib

kspeakman

namespace Utilities

type EventType = string
type EventData = string

type EventParser<'union, 'meta> =
    {
        Deserializers : Map<EventType, EventData option -> Result<'union, exn>>
        Serialize : 'union -> Result<EventType * EventData option, exn>
        ParseMeta : string -> Result<'meta, exn>

kspeakman

Ref: elmish/elmish PR #248.

An early prototype of the "live subs" demo used the subscription settings + Msg type as the subscription ID. This worked as long as you only needed a single subscription. But it did not allow, for example, two timers on the same page with the same settings. That led me to switch to a user-provided Sub ID. This gives the user full control on when subscriptions are different or the same. It also gave ID the responsibility of triggering changes to a running subscription.

Subscriptions only have start/stop semantics. So "change" means stopping the running one and starting a new one with different settings. How ID controls this is illustrated in the live subs demo. Notice under Subscriptions -- which lists subscription IDs -- that the timer interval is part of the ID. When the user changes the interval from 1000 to 2000, the subscription ID goes from ".../interval/1000" to ".../interval/2000". T

kspeakman

module Emailer

type Model =
    { SendLimitPerSecond: int
      Today: DateTime
      ToSend: Email list list }

type Effect =
    | FindDueEmails of DateTime
    | ScheduleSend of DateTimeOffset

kspeakman

    // F# type alias
    type Builder = IApplicationBuilder -> IApplicationBuilder

    let createWebServer settings =

        let createBuilder () = (WebHostBuilder(), [])

        let setConfig basePath (host: IWebHostBuilder, configs: Builder list) =
            ( host
                .ConfigureAppConfiguration(fun (_: WebHostBuilderContext) (builder: IConfigurationBuilder) ->

kspeakman

Fri Mar  9 12:34:56 2018: Fri Mar  9 12:34:56 UTC 2018
Fri Mar  9 12:34:56 2018: urandom start: failed.
Fri Mar  9 12:34:56 2018: ALSA: Restoring mixer settings...
Fri Mar  9 12:34:57 2018: INIT: Entering runlevel: 5
Fri Mar  9 12:34:57 2018: Starting system message bus: dbus.
Fri Mar  9 12:34:57 2018: Starting bluetooth: bluetoothd.
Fri Mar  9 12:34:57 2018: Starting syslogd/klogd: done
Fri Mar  9 12:34:57 2018: bcm43xx_init
Fri Mar  9 12:34:57 2018: Flash firmware /lib/firmware/brcm/BCM43430A1.hcd
Fri Mar  9 12:35:02 2018: Set Controller UART speed to 921600 bit/s

kspeakman

module Ssm

module GetParametersWorkflow =

    open Amazon.SimpleSystemsManagement.Model
    open System.Net

    type Failure =
        | ParameterRequestFailed of exn
        | ParameterRequestError of HttpStatusCode * Amazon.Runtime.ResponseMetadata

kspeakman

namespace Utils

module Async =

    let retn x =
        async { return x }

    let lift f =
        f >> retn

kspeakman

    // differences from Utf8Json GuidBits
    // * parses Base64 encoded Guids
    // * writes Guids without '-' character
    
    [StructLayout(LayoutKind.Explicit, Pack = 1)]
    public struct GuidBits
    {
        [FieldOffset(0)]
        public readonly Guid Value;

kspeakman

module ListFolds exposing (..)

{-| Alternative implementations of List.foldl and List.foldr
    
    -- this will add the `fold` and `foldBack` functions to the List module
    import ListFolds as List
    
    List.fold (++) "" [ "Hello", " ", "World", "!" ] == "Hello World!"
    
-}