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learning smalltalk with Google Code In
code-in | collaboration | smalltalk

For years i have been meaning to learn smalltalk. my first exploration started about 10 years ago while teaching two children to make a game with squeak. Then i worked through a tutorial about making a simple game. Unfortunately it didn't capture my interest. So the my attempts to learn smalltalk were stalled as i searched for a project that i could do with it.

Why do i want to learn smalltalk? Because it is the first object-oriented language. Many of the OO concepts were invented in smalltalk. There is also the concept of working in an image that not only contains my code but also a full IDE which is used to update my code at runtime. Updating code at runtime is a concept that has been with me for more than 20 years now, ever since i started programming MUDs in LPC and writing modules for the Spinner/Roxen webserver in Pike. Pike allows recompiling classes at runtime. Any new instances will be made from the new class, while old instances remain as is. If the compilation fails, the class is not replaced and the old class continues to work. This way it is possible to make changes on a live server without restarting and disrupting ongoing requests. A decade later i discovered sTeam, the platform that also drives this very website. It takes this process even further: sTeam persists code and objects in a database. While in Roxen objects live as long as it takes to process a request, in sTeam objects are permanent, much like in a smalltalk image. sTeam then adds the capability to update live objects with new class implementations. The image concept of smalltalk is therefore already very familiar, and the major difference is smalltalk's GUI.

Recently a friend asked me what it would take to build a text search application for the Baha'i writings in chinese. There is one for english and other western languages, but not for chinese, and it does not run on mobile devices. It is also not Free Software, so i can't use it as a base to improve. But i didn't really want to take on a new project either so i just filed the idea for the time being.

One of my customers is managing access to several internal resources through htaccess and htpasswd. Because they have many interns who need to have access to some of these, and because they are now spread over multiple servers, it is becoming more and more cumbersome to manage them manually via these files. It also does not help that a salt module which we could use to help depends on apache helpers, which we can not install because apache conflicts with nginx which we are using. So i started exploring alternatives. One such alternative is a different way for nginx to verify access. It can make a request to an external service which then grants or rejects access depending on the resource and credentials. This could be implemented as a webservice with a webinterface to manage the users. I looked for some existing applications that would get me part of the way but i found nothing suitable.

Enter Google Code-In: FOSSASIA invited the BLUG to join them as mentors.

At first i put up tasks for the community-calendar project, but then i realized that this was an opportunity to explore new ideas. Figuring that teaching is the best way to learn i put up those project ideas as tasks for the students. I could ask students to learn and explore, and finally work on those projects. I would pick the technology and guide the students through a sequence of tasks to acquire the skills needed to implement the actual applications. This was my chance to get back into smalltalk. Since code-In targets middle and highschool students, it is quite unlikely that any of them already know smalltalk, or have even heared about it. so in a way this will introduce a few students to smalltalk. I picked pharo because i feel it is going in the right direction trying to improve itself and also adding things like commandline support.

The desktop application was straight-forward: find out how to embed text-documents in the image and make them searchable.

The web application took more exploration. I wanted to do it with a RESTful api and a javascript frontend. Again, the frontend was easy to define: create a user management interface. For the backend, the question was which webframework to use? AIDA/web has builtin user management and REST style url support by default. Seaside includes a REST module, but both are strong on generating html which i am not interested in. Then there is iliad, which appears more lightweight. Eventually i figured i could just let the students explore each, and i created a task for each tutorial that i could find:

(some of these i repeated because the student who did the them first time didn't pick up the follow-up tasks.)

Finally i discovered that Zinc, the HTTP server used by most frameworks is powerful enough to build a RESTful API without all the templating extras that the above frameworks provide. I also discovered teapot, a microframework that might be useful.

Once the students are familiar with the smalltalk environment, they can move on to the next steps:

Of course there are also tasks for the front-end

Related is also this task about a file editor, which i believe should make it easier to edit static assets like html and css pages from within the image:

Author : mbaehr   |   size : 8501Bytes   |   Publish Date : Dec/31/14/05:59   |   to Top