How to drop all tokens that a snowball dictionary cannot stem?

Hi everybody,

I am trying to get all the lexemes for a text using to_tsvector(). But I want only words that english_stem -- the integrated snowball dictionary -- is able to handle to show up in the final tsvector. Since snowball dictionaries only remove stop words, but keep the words that they cannot stem, I don't see an easy option to do this. Do you have any ideas?

I went ahead with creating a new configuration:

-- add new configuration english_led
CREATE TEXT SEARCH CONFIGURATION public.english_led (COPY = pg_catalog.english);

-- dropping any words that contain numbers already in the parser
ALTER TEXT SEARCH CONFIGURATION english_led
DROP MAPPING FOR numword;

EXAMPLE:

SELECT * from to_tsvector('english_led','A test sentence with ui44 \tt somejnk words');
to_tsvector
--------------------------------------------------
'sentenc':3 'somejnk':6 'test':2 'tt':5 'word':7

In this tsvector, I would like 'somejnk' and 'tt' not to be included.

Many thanks,
Christoph