I use regular expressions in several places to pull out subsets. ChatGPT wrote a nice javascript parser for me which allows expressions like "rbsp AND density" and this morning I started a project where it supports these expressions in Java. I need to go through and make sure all sites are using this.
I wrote HAPI support and CDAWeb. URI history still needs to be done.
CDAWeb doesn't keep the entire filter in the URI, just keeping the first token.