oh sure, there is a nice mapping between parser combinators and lbnf, however most programmers have little experience of fp and don't want to touch haskell for anything. this might be unpopular, but it has the unfortunate property of being a true statement. i'm happy to be downvoted for 'trolling'
i had seen that kaleidoscope tutorial in the LLVM docs before but didn't remember it particularly or find it helpful - perhaps its the presentation but this site is much more polished than that part of the llvm docs. granted they make the explicit choice to not use lexer/parser generators but that is not as practical in c/c++ as it is with haskell and adds a lot of needless cruft imo.