Support for Chapter 23: GUI programming with gtk2hs

This directory contains all that is needed to compile and run the application from the chapter 23.

The starting point was that I wasn't able to install the glade hackage package in a recent Haskell environment, so I picked the most recent older GHC version the glade library was tested with (version 8.0.1) and aligned everything else to it.

It was created and tested on Slackware64 15.0 Linux distribution, but it should be possible to use it as a guide for running the chapter 23 on other Linux distributions or maybe even other operating systems. For full reproducibility, Slackware64 15.0 is assumed.

There was still a need to do minor changes to the code of the chapter. The patch is included in this directory.

The result

In the terminal, you can see patching the original code of the chapter 23, activating the environment, compiling and running the PodLocalMain application. There is also a GTK 2 Glade editor running.

The main.sh script

The main script automates installation of the environment. It * downloads all binary and source archives needed * verifies SHA256 sum of every downloaded archive * installs the GHC compiler * installs libraries related to GTK 2 * installs the Haskell packages * installs the Glade designer for GTK 2 for the full experience :-) * creates a bash script for activating the installed environment.

The script installs everything in a single directory. It doesn't modify anything outside of it. Uninstallation is just removing that directory.

Steps

The steps for getting the chapter 23 to run are 1. Installing the environment 2. Activating the environment 3. Patching and compiling the application

See the terminal in the screenshot above for the activation, patching, and compiling.

Installation

1. Install Slackware64 15.0. The DVD image is at the Slackware ISO mirrors. It contains the software needed. I installed the system in a virtual machine. For simplicity I did full installation. It needs about 15 GB, so give the virtual system at least 25 GB to have enough space for the downloaded and installed files. If you are not a Slackware user, for booting into the graphical environment
2. log in as root
3. run adduser to add an unprivileged user
4. edit /etc/inittab (e.g., by nano editor) and change the id:3:initdefault: line to id:4:initdefault:

5. reboot the system

6. Get this directory. You can copy it into the virtual machine via a directory shared with the host OS or git-clone it from inside.

7. Run the main.sh script inside this directory. It creates a root directory in the current directory and installs all files there.

Activation

The activation script env is in the root directory created by the main.sh in DESTDIR. Source it in your bash session. It sets environment variables (PATH, LD_LIBRARY_PATH) to include and prefer the installed GHC version, libraries, and executables.

This is done every time you want to compile and run the chapter 23. Running other programs may not work because of the overriden paths to the libraries. Run those in a normal shell session without the environment activated.

Patching the code of chapter 23

Go to the directory with code for the chapter and run

patch -p1 < /path/to/the/ch23.patch
patch -p1 < /path/to/the/ch23_https.patch

The second patch is not necessary for getting the code to compile, but it enables HTTPS support for testing the podcast downloader with modern podcast feeds which are accessible via HTTPS. The original downloader support only HTTP.

Compiling and running the application

With the environment activated, run

> ghc PodLocalMain.hs
> ./PodLocalMain

GTK 2 Glade designer

The designer is run by glade-3 command when the environment is activated. Note that running just glade command runs the GTK 3 Glade designer included in Slackware64 15.0 which cannot edit GTK 2 glade files.