jackfoxy

(*
Decision Table Demo

MIT License, do with this what you will

A demo of decision tables using F# types and pattern matching, inspired by https://www.hillelwayne.com/post/decision-table-patterns/

The compiler service flags problematic (incomplete) decision tables.

Requirements:

jackfoxy

#r "<path to nuget>/.nuget/packages/fsharp.data/3.3.2/lib/netstandard2.0/FSharp.Data.dll" 

open FSharp.Data
open System


 type Comment =
    {
        Url : Uri
        Tag : string

jackfoxy

// Fibonacci
// not originally mine, can't remember where I got it

// State Monad combined with Continuation Monad (StateT Mondad transformer)
type StateContMonad<'s, 'a, 'r> =
    StateContMonad of ('s -> ('s -> 'a -> 'r) -> 'r)

type StateContBuilder() = 
    member __.Return value =
        StateContMonad (fun state k -> k state value)

jackfoxy

//not tested as fsx, but insert into existing fs in a project and you should see error messages other than bad tab
//did not let me save gist with tabs
//so insert them yourself in some other editor in line 21
type Production = 
    {
        Ident : int
        Year: int
        Month: int
        OilProduced: float
        WaterProduced: float

jackfoxy

one name publlic verification

jackfoxy

/// <reference path="C:\Users\Jack\AppData\Local\Microsoft\VisualStudio\14.0\Macros\dte.js" />
// Blog announcing new VS macro facility:
// https://blogs.msdn.microsoft.com/visualstudio/2016/05/11/macros-extension-open-sourced-in-visual-studio-2015
//
// Macros get saved to:
// <user>\AppData\Local\Microsoft\VisualStudio\14.0\Macros\Macros
// does not seem to be any way to change default folder. Roaming may also work, but I have not experimented with that.
//
// Tne open source project:
// https://github.com/Microsoft/VS-Macros

jackfoxy

//Demo SQLite cannot run from FSI
//#load "load-references-debug.fsx"
#I __SOURCE_DIRECTORY__

#r "../../packages/Microsoft.Data.Sqlite.1.0.0-rc1-final/lib/net451/Microsoft.Data.Sqlite.dll"

open Microsoft.Data.Sqlite

let conn = new SqliteConnection(@"Data Source = :memory:") 

jackfoxy

namespace TypeSystemSandbox

#if INTERACTIVE
#load @"C:\FsEye\FsEye.fsx"
#I "C:\Packages" 
#endif

open System

//constraints from "Constraints (F#)" MS F# Language Reference

jackfoxy

let forcedReveal doorWithPrize fstChoice = 
    match (doorWithPrize + fstChoice) with
    |3 -> 3 
    |4 -> 2  
    |_ -> 1

jackfoxy

let forcedReveal doorWithPrize fstChoice = 
    match doorWithPrize with
    |1 -> if fstChoice = 2 then 3
          else 2 
    |2 -> if fstChoice = 1 then 3
          else 1  
    |_ -> if fstChoice = 1 then 2
          else 1