mydeco-dev-team/xappy — comment on commit 6173c25428d2911db14e7a0b51c2b2904f432a19
File: xappy/fieldmappings.py line 58
By rboulton:

Why can the letter R only appear at the end of a prefix?

R is used to denote stemmed words, but only appears _before_ the prefix starts in this case; all Xappy auto-generated prefixes start with an X, so this is not an issue.