Google Summer of Code 2012

Project Description: PicoLisp is one out of many Org Babel languages, but may be special in the sense that it does not only contribute to the static webpublishing capacities, but may introduce dynamic webprogramming on top of a real database into Org Mode.

Real interactive webprogramming frequently involves a (SQL) database like MySQL, a programming language like PHP or Python to build a MVC (Model-View-Controller) application on top of the database, a web framework for that programming language to make the programmers life easier (e.g. Django for Python), and a persistence layer that abstract away the conceptual mismatch between the SQL database and the (mostly) object-oriented application. Sometimes, a WYSIWYG html editor like MS Frontpage is invovled too, when webdesigners design the UI of the application.

Such an application needs user input (via <form> or <input> elements in the html pages) and needs to adapt dynamically to the users actions and queries by updating either the whole page or only parts of it (Javascript). For each user, a session is needed to keep track of the state of the application during his/her visit.

This kind of dynamic webprogramming can't be done with Org Mode. Typical webpages made with Org Mode are static in nature, even if they update their content frequently with some cron jobs on the server. There is no interaction with the user.

Considering the web stack for dynamic web apps described above, Org Mode really functions as a kind of 'Frontpage on steroids' for highly skilled academics. The project idea is to let PicoLisp replace all the other elements of the webstack and combine Org Mode and PicoLisp into an entirely Lisp-based framework for dynamic web programming.

In the PicoLisp application framework, UI and database are unified. Database objects are first class members of the language, and the UI elements act directly on this object-oriented lisp database (that is fast and scalable). No external SQL storage is needed, no persistence layer between the relational world of the DB and the object-oriented world of the application, and no glue code (controller) that connects the view to the model.

By merging PicoLisp's framework for rapid web-application development with Org Modes framework for rapid (web-) content production via Org Babel, new kinds of websites produced with Org Mode should become possible.

Difficulty: Medium

Requirements: Elisp, PicoLisp

Recommended: Knowledge about the inner workings of Org-babel and the PicoLisp application programming framework, some experience with Git.

Mentors: Bastien Guerry, Eric Schulte

Project Description: This project idea is about writing a git merge driver for Org mode files, in the way git-merge-changelog does this for GNU style ChangeLog files?

One of the obstacle for using Org-mode for collaborative programs is that many operations add or remove text from the beginning or end of a file, or which add or remove a subnode from an outline tree. These are operations that confuse the git merger, in particular if two people have added something to a file, or removed/added sequential sibling nodes.

I believe that this could be solved with a dedicated merge driver that understands the integrity of an outline (sub)tree, and that knows that the sequence of two new subtrees added by different people does not matter.

The idea for this is actually (I believe) from Brian Gough who asked me about it at FOSDEM. I have now also run into this problem and would really find it great if such a merge driver could be written.

Difficulty: Hard

Requirements: Git, Elisp, C

Recommended: Good understanding of Git and the structure of Org-mode files.

Mentors: Carsten Dominik

Project Description: Ragel http://www.complang.org/ragel/ is a tool that integrates regular expressions and state machines under one umbrella. It has backends currently for C, C++, Objective-C, D, Java and Ruby. Programming an Elisp backend would be a manageable task for a GSoC project.

After that org-mode code might become half as long and twice as fast - at least those sections that are heavily regex oriented.

Difficulty: Medium

Requirements: Elisp, RegExp

Recommended: Familiarity with Org-mode, regular expressions and state machines.

Mentors: Bastien Guerry, Rustom Mody, Nicolas Goaziou

Project Description: Implementing a multi-programming-language "notebook" like console interface build on top of Org-mode and Babel (with both Emacs and HTML interfaces).

Difficulty: Medium

Requirements: Elisp, HTML

Recommended: Familiarity with Org-mode and Babel

Mentors: Eric Schulte

Project Description: Adding support for asynchronous code block execution.

Difficulty: Medium

Requirements: Elisp, C

Recommended: Good understanding of Org Babel and the GNU/Linux process model.

Mentors: Eric Schulte

Project Description: Adding support for piping results between code blocks allowing many blocks to run concurrently (probably best combined with asynchronous execution).

Difficulty: Medium

Requirements: Elisp, C

Recommended: Good understanding of Org Babel and the GNU/Linux process model.

Mentors: Eric Schulte

Project Description: Adding support for handling output written to STDERR.

Difficulty: Medium

Requirements: Elisp

Recommended: Familiarity with Org Babel and GNU/Linux.

Mentors: Eric Schulte