custom preprocessing steps: filters?

[bjdmeest]

So, I kind of miss the latex macro's but I'm pretty sure it's easy to include them.

Stuff like registering custom shortcuts, so that I can write a small regex so that

And then I will make X\todo.

gets changed to

And then I will make X*.*{:.todo}.

Would adding a custom filter be appropriate for this? Are there resources available for including custom preprocessing filters to a paper repo?