>...and I've just blogged about some of the issues one can run into with this >sort of project, hope this is useful! http://www.flax.co.uk/blog/2016/05/13/old-new-query-parser/
+1 completely non-trivial task to roll your own. I'd add that incorporating multiterm analysis (analysis/normalization of wildcard, fuzzy, prefix, regex, etc) is a fundamental requirement too often overlooked. If you don't do this correctly, you'll get results, but not all that you should be getting -- you won't know what you can't find. :) It would be great if Uwe could add a check for improperly ignoring normalization of multiterms to his forbiddenapis. :)