Currently Solr makes it easy to use english stopwords for StopFilter or CommonGramsFilter.
Recently in lucene, we added stopwords lists (mostly, but not all from snowball) to all the language analyzers.
So it would be nice if a user can easily specify that they want to use a french stopword list, and use it for StopFilter or CommonGrams.
The ones from snowball, are however formatted in a different manner than the others (although in Lucene we have parsers to deal with this).
Additionally, we abstract this from Lucene users by adding a static getDefaultStopSet to all analyzers.
There are two approaches, the first one I think I prefer the most, but I'm not sure it matters as long as we have good examples (maybe a foreign language example schema?)
1. The user would specify something like:
<filter class="solr.StopFilterFactory" fromAnalyzer="org.apache.lucene.analysis.FrenchAnalyzer" .../>
This would just grab the CharArraySet from the FrenchAnalyzer's getDefaultStopSet method, who cares where it comes from or how its loaded.
2. We add support for snowball-formatted stopwords lists, and the user could something like:
<filter class="solr.StopFilterFactory" words="org/apache/lucene/analysis/snowball/french_stop.txt" format="snowball" ... />
The disadvantage to this is they have to know where the list is, what format its in, etc. For example: snowball doesn't provide Romanian or Turkish
stopword lists to go along with their stemmers, so we had to add our own.
Let me know what you guys think, and I will create a patch.