A simple, possibly correct LR parser for C11 [pdf]

A simple, possibly correct, implementation: https://github.com/jhjourdan/C11parser

Here, if the else branch is attached to the second if construct, then the last occurrence of T must denote a variable, which implies that the program is syntactically invalid. One might therefore interpret paragraph 6.8.4.1, §3 as dictating that the else branch be attached to the first if construct. Under this interpretation, the last occurrence of T would denote a typedef name, and the program would be syntactically valid.

That's pretty cool.