jeff.dallien.net

I’m expecting to write two chain posts today. The next post will have some actual code, this one has some thoughts on the direction the code will be going until I learn more.

As someone who has spent most of their time using a Prolog interpreter that is not SWI-Prolog, I am mindful of how it can be frustrating to find some interesting looking project only to find that it relies on an SWI library which doesn’t have an equivalent available for another interpreter. While I do believe in using the best tool for the job, I would also like to produce a solution that people can use with the interpreter with which they are already comfortable and in which they have existing code.

For the first time I can finally see why people write code using an SWI library and never look back. So far, the HTTP library has provided some solution to all the basic things I’ve needed and I think I’ll be able to focus on the overall application design much sooner than I expected because I figured I would be dealing with all kinds of lower level HTTP issues. At the moment I have no idea how many websites are running on Prolog but this library really makes the web pretty accessible to any existing Prolog programmer if they care to take the time to write the HTML generating parts.

I am going to stick with the SWI-Prolog libraries for now, but my long term goal is still to provide a web solution compatible with more than just SWI-Prolog. I don’t think I could design a good interface from the ground up without being familiar with what’s already done anyway. Recently I was talking to Terry Swift, a core developer for XSB and he mentioned that some Prolog implementations were looking to have better library compatibility with each other, so that may include the HTTP library I’ve been using.

Wishlist

• A way to use full HTML pages with some Prolog inside to add the dynamic parts, similar to how ERB is used in Rails. So far the page generating code has all been similar to Ruby’s Builder but with more punctuation, and it really feels like the entire page should not be generated by code. The Prosper framework may have had a solution for this, I will need to investigate.