It's often I stumble upon discussion mentioning the term LL and LR and other stuff related to parsing[0]. Without a proper CS background, it's quite hard to follow along. That first link[1] and the wikipedia page[2] mentioned there are really great. Many thanks for posting those. It really shed some light about those terms.

[0]: https://jeffreykegler.github.io/personal/timeline_v3

[1]: http://blog.reverberate.org/2013/07/ll-and-lr-parsing-demyst...

[2]: http://en.wikipedia.org/wiki/Tree_traversal