The corpus directory, absolute: root if given, else $OPENKA_CORPUS, else
$XDG_DATA_HOME/openka, else ~/.local/share/openka. Every path is resolved as
given, untrimmed. An environment variable that is empty or only whitespace counts
as unset — the shell's OPENKA_CORPUS= ka …; a blank root is refused with
OpenKaValidationError, since a caller who names a path means one.
The corpus directory, absolute:
rootif given, else$OPENKA_CORPUS, else$XDG_DATA_HOME/openka, else~/.local/share/openka. Every path is resolved as given, untrimmed. An environment variable that is empty or only whitespace counts as unset — the shell'sOPENKA_CORPUS= ka …; a blankrootis refused withOpenKaValidationError, since a caller who names a path means one.