[Snowball-discuss] French stemmer question

[Olly Betts]

On Mon, Nov 09, 2020 at 01:33:36PM -0800, Martin Holmes wrote:
> Looking at the stemming algorithm description for French here:
> 
> <https://snowballstem.org/algorithms/french/stemmer.html>
> 
> I see this:
> 
> "...if preceded by eus, delete if in R2, else replace by eux if in R1..."
> 
> However, R2 is contained in R1, so the logic seems reversed to me.

As you say R2 is within R1, so if the suffix isn't in R2 it can still be
in R1.

The R1/R2 example "fameusement" further up actually illustrates this
case.

The "-ement" suffix is in RV so removed.  This is preceded by "-eus"
which isn't in R2 but is in R1, so it's replaced by "eux" and the
stem is "fameux".

So this seems OK to me.

> Shouldn't it be:
> 
> ...if preceded by eus, replace by eux if in R1, else delete if in R2...

If the suffix in question is not in R1 then it won't be in R2 either,
so the "else ..." part in your version seems to be redundant.

If there's some ambiguity in how this can be interpreted we can try to
improve the phrasing.

Cheers,
    Olly