Summary

Fixes https://gitlab.com/caosdb/caosdb-server/-/issues/203

Focus

Allow "has" after brackets. E.g.:

• FIND ename WHICH ( HAS pname )
• FIND ename WHICH ( HAS pname and references ename2 )

Notes

This fixes the given bug. However, I would like to raise the question whether the change should go further.

We allow queries like FIND ename WHICH HAS pname WHICH HAS pname2 and since HAS can be interpreted as WHICH HAS we can also write FIND guitar which ( HAS latitude) (Brackets prevent "which has" to be consumed at once. Thus because the expression for the entity can be omitted, it cannot be distinguished, whether this is a "which has" where for some reason brackets where inserted or whether it is a "which has a X which has a Y".

I would suggest to simplify things by not treating "HAS" as "WHICH HAS". When we look in the parser, the which_exp always requires some "which" like part ("which" itself, "with" as "synonyom" for "which has", "where", etc.). Except for "HAS". Introducing this change would make clear that a which_exp means another level, i.e. usually a subproperty. This would also make clear, that all parts of "HAS A PROPERTY" are syntactic sugar and can be omitted. It is not sometimes sugar and sometimes not. (see !87)

Test Environment

unit test

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