Hello everyone,
I'm interested in porting texvc to Python, and I was hoping this list here might help me hash out the plan. Please let me know if I should take my questions elsewhere.
Roughly, my plan of attack would be something like this:
1. Collect test cases and write a testing script Thanks to avar from #wikimedia, I already have the <math>...</math> bits from enwiki and dewiki. I would also construct some simpler ones by hand to test each of the acceptable LaTeX commands.
Would there be any possibility of logging the input seen by texvc on a production instance of Mediawiki, so I could get some invalid input submitted by actual users?
This could also be useful to future maintainers for regression testing.
2. Implement an AMS-TeX validator I'll probably use PLY because it's rumored to have helpful debugging features (designed for a first-year compilers class, apparently). ANTLR is another popular option, but this guy http://www.bearcave.com/software/antlr/antlr_expr.html thinks it's complicated and hard to debug. I've never used either, so if anyone on this list knows of a good Python parsing package I'd welcome suggestions.
3. Port over the existing tex->dvi->png rendering. This is probably just a few calls into the subprocess module. Yeah, I just jinxed it.
4. Add HTML rendering to texvc and test script I don't even understand how the existing texvc decides whether HTML is good enough. It looks like the original programmer just decreed that certain LaTeX commands could be rendered to HTML, and defaults to PNG if it sees anything not on that list. How important is this feature?
5. Repackage the entire Math thing as an extension I might do this if I have time left at the end. I'm sure the project will change over the summer.
Python doesn't have parsing just locked right down the way C does with flex/bison, but there are some good options, I have the most experience with it, and I think I'd be able to complete the port faster in Python than in either of the other languages. I was tempted at first to port to PHP, to conform with the rest of Mediawiki, but there don't seem to be any good parsing packages for PHP. (Please tell me if that's wrong.)
I'd appreciate any advice or criticism. Since my only previous experience has been using Wikipedia and setting up a test Mediawiki instance for my ACM chapter, I'm only just now learning my way around the code base and it's not always evident why things were done as they are. Does this look like a reasonable and worthwhile project?
Yours, Damon Wang
P.S. Some of you may remember me on IRC a couple of days ago getting a little panicky about not knowing OCaml, but I'm a bit more hopeful now after looking around the source. I definitely have to keep the OCaml manual open for reference, but I've written Scheme, Common Lisp, and Haskell before, so I think I might be able to fake it. These are just Famous Last Words waiting to happen, I know.