[Xapian-discuss] QueryParser, mapping a single prefix to multiple fields ?

[Daniel Ménard]

Hello,

The doc for QueryParser::add_prefix and QueryParser::add_boolean_prefix 
says that "multiple fields can be mapped to the same prefix", which is 
very convenient to handle aliases.

But I am in the opposite situation where I would like to map a same 
prefix to multiple fields: for example, a search for 'title:xapian' 
would look for 'XTITLEFRExapian' or 'XTITLEENGxapian'.

What would be the best way to achieve this? (I'm using the PHP bindings)

 From what I see, this is not something which is currently supported. If 
I call multiple times add_boolean_prefix with the same 'field', only the 
first prefix is taken into account.

A solution would be to 'duplicate' search terms, adding a prefix like 
'XTITLE ENG AND FRE', but this is obviously a waste of resources.

For now, the only solution I see is to pre-process the user request 
before giving it to the query parser (replace "title:something" with 
"titleeng:something OR titlefre:something" for each field I want to 
handle like this)... which is not very elegant.

Perhaps it would be a useful feature to add to the query parser? It 
would not break the API (just call add_prefix / add_boolean_prefix 
several times with the same field and different prefixes) and I don't 
think it would break any existing code.

Of course ;-) , I'm not fluent enough in C++ to code that myself, and I 
don't even know if I ask for a simple change or a big one!

Please let me know...

Best regards,

Daniel