Allow SSS a precursor fragment searches #32
Description
A couple of users have suggested that it would be very useful to be able to specify a more generic structure as a query. e.g. to specify a substructure search. An example would be a search that contained a benzene or pyridine ring, by use of a SSS that used [C,N] as a list atom at that position.
This should in principle be possible as RDKit now has support for Neo4j (see https://github.com/rdkit/neo4j-rdkit). With this we would be able to first run a SSS against the :F2:Mol nodes and then expand out around each of the results using neighbourhood or expansion searches.
This is potentially a risky development as:
- It requires getting the RDKit integration working
- The RDKit code may not be that robust at present as it's not been used much in anger
- It may have significant impact on the grouping code for neighbourhood searches
Another alternative that avoids the use of RDKit in Neo4j might be to allow to expand that initial search using Murco frameworks.