F# exercises designed for a 1 day workshop

• Prerequisites
• Workshop timing
• Projects
  • Profiles
  • Game of Life

Prerequisites

One of the following should be enough for you to run the exercises:

• Visual Studio 2013 / 2015 (Windows only).
  • If you already have Visual Studio, you may need to download and install F# explicitly.
• Xamarin Studio (OS/X or Windows).
• MonoDevelop (Linux, OS/X or Windows).
• Vagrant and VirtualBox simply by running vagrant up in the root of the repository.

Workshop timing

Here are some guidelines as to how the workshop will be broken down:

Start time	Exercise	Files
09:00	Introductions, setup your REPL
09:30	Functions, the core of the language!	functions.fsx
10.30	Tuples	tuples.fsx
11.00	Coffee break
11.15	Records	records.fsx
11.45	Discriminated unions & pattern matching (part 1)	ADT1.fsx ADT2.fsx ADT3.fsx ADT4.fsx
12.15	Lunch
13.00	Recap of concepts covered so far, opportunity to ask questions
13.30	Discriminated unions & pattern matching (part 2)	pattern_matching1.fsx pattern_matching2.fsx
14.15	Working with lists	lists1.fsx lists2.fsx lists3.fsx lists4.fsx
15.15	Break
15.30	Real world example: form validation for a web application	profiles

Projects

Profiles

The project in the profiles folder is a simple web project that implements simple API validation using the suave web framework:

• The validation should be implemented in profiles.server/Profile1.fs. The sample provided shows validating that the firstname is a required field.
• Tests for all validations are provided in profiles.tests/Profile1Tests.fs. You should keep adding validations until all the tests pass.

To run the tests:

• Lin: ./build.sh RunTests
• Windows: ./build.cmd RunTests

To run the web app:

• Linux: ./build.sh Run
• Windows: ./build.cmd Run

The site should be available on http://localhost:3000.

Some useful functions:

• Char.IsDigit : char -> bool
• Char.IsLetter : char -> bool
• String.Concat : seq<'t> -> string

Also remember that string is a sequence of characters. For example the following expression results in the string "1":\

"profile1" |> Seq.filter Char.IsDigit |> String.Concat

Game of Life

The project in the life folder is a suave based game of life web application with some critical elements removed.

The UI is a modified version of http://www.julianpulgarin.com/canvaslife/ that moves the computation to the server.

Several critical elements have been removed and are left as an exercise:

1. The easiest missing piece is to enable the sample patterns to be loaded. You should use the dataStore to load the pattern and return it as the response body (Life.Server/Program.fs).
2. The next piece is to implement the game of life algorithm. The web part of this has been wired up for you but the implementation in: Life.Server/Game.fs is missing.
3. The final piece is enable patterns to be saved:

• You will need to implement the run length encoding algorithm: Life.Server/RLE.fs.
• You will then need to implement the PUT endpoint: Life.Server/Program.fs.

Make use of the Life.Tests project that already has xUnit configured.

To run the tests:

• Linux: ./build.sh RunTests
• Windows: ./build.cmd RunTests

To run the web app and restart the server when source changes:

• Linux: ./build.sh Watch
• Windows: ./build.cmd Watch