davidglassborow

(*
An incomplete implementation of a type-safe SQL query in F#.

The idea is that a query is built up clause by clause, by representing
each additional clause being added on to the query as a state transition
between different types of queries. We capture these different types as
phantom types to make sure that only valid transitions (query clause
additions) as defined by us can be carried out.

The final result is a 'total query' that can be converted to a string,

davidglassborow

Homebrew Permissions Denied Issues Solution

Installing and fixing node.JS

---

brew install node

davidglassborow

Deploying an F# ASP.NET Core app to Azure

Last week I spent a lot of time trying to deploy an F# ASP.NET Core app (a Giraffe app, specifically) to Azure because the information to complete all the steps was scattered in several places. So I'm writing this hopefully it will save the pain to others :)

Preparation

The following steps are mostly taken from this guide and it's only necessary to do them once:

1. Create an account in Azure (or use an existing one)
2. Create a resource group (or use an existing one)

davidglassborow

How to get on Rinkeby Testnet in less than 10 minutes

Following instructions from the excellent https://www.rinkeby.io/

Synchronizing a Full Node

A full node lets you access all state. There is a light node (state-on-demand) and wallet-only (no state) instructions as well,

davidglassborow

open System.Collections.Generic
open Microsoft.FSharp.Collections


[<RequireQualifiedAccess>]
module Folds =

    // These are the fast implementations we actually want to use

davidglassborow

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

davidglassborow

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

davidglassborow

#r "../packages/FSharp.Data.2.2.5/lib/net40/FSharp.Data.dll"
open System
open System.IO
open FSharp.Data

[<Literal>]
let lineBreak = "\r\n"

type CommitInfo = {Hash : string; Author : string; TimeStamp : DateTime; Message : string}
type CommittedFile = {LinesAdded: int option; LinesDeleted: int option; FileName: string}

davidglassborow

type BusyBuilder(blockUi, unblockUi) =
    member this.Bind(x, f) = async.Bind(x, f)
    member this.Combine(e1, e2) = async.Combine(e1, e2)
    member this.Delay(f) =
        async {
            blockUi ()
            let! result = async.Delay f
            unblockUi ()
            return result
        }

davidglassborow

namespace Topshelf

[<AutoOpen>]
module Topshelf =

  open System
  open Topshelf.HostConfigurators
  open Topshelf.Runtime

  let configureTopShelf f =