My day job used to involve parsing some fairly ill-formed languages, so I developed this: https://github.com/Logicalshift/TameParse

I noticed with the languages I was working on, the problems could be resolved by being smarter with the lookahead: this parser allows for context-free lookahead matching to resolve (or detect and defer) ambiguities.

That makes it possible to do neat things like parse C snippets without full type information or deal with keywords that aren't always keywords (eg, await in C#).