memoi.se

memoi.se is a complete web application written in Haskell, designed to be used as a reference by beginners. By looking at the git commit history of this repository, you can see a series of changes, building up from a simple "Hello, world!" app to a fully-functional hyperlink shortener with PostgreSQL database integration, in under 100 lines of Haskell.

Getting Started

Begin by entering the following commands into your terminal window. You'll need to have Haskell installed.

$ git clone git://github.com/ryantrinkle/memoise
$ cd memoise
$ git checkout lesson-1
$ cabal install
$ ./dist/build/memoise/memoise

Now, open a browser and go to http://localhost:8000/.

You should see "Hello, world!" displayed. If you look at src/Main.hs in lesson-1, you can see that this is achieved with just a few simple lines of Haskell.

To shut down the memoi.se server, press Ctrl-C in your terminal window. Once you've taken a look around in Lesson 1, you can move on to Lesson 2 by running

$ git checkout lesson-2
$ cabal install
$ ./dist/build/memoise/memoise

Lessons

Although looking at the checked out code may be helpful, a more informative way to look at this project is by viewing the commit history. Each lesson is a single git commit, designed to add a single piece of functionality, as you might do if you were creating a website from scratch.

You can take a look at the changes made in each lession here:

• Lesson 1
• Lesson 2
• Lesson 3
• Lesson 4
• Lesson 5
• Lesson 6
• Lesson 7

Note: You need PostgreSQL installed for Lessons 8-11.

• Lesson 8
• Lesson 9
• Lesson 10
• Lesson 11