Currently the filters and featureWriters parameters always override the ones defined in the UFO lib.plist, and it's impossible to extend instead of replace these, e.g. inserting some additional filter or writer either before or after.
This PR allows to pass a special value ... (the actual Ellipsis singleton, not the str literal '...') in both these lists, which acts as a placeholder to signal one wants to extend the list of predefined filters/writers.
The ellipsis is replaced by the custom filters defined in the UFO lib (if any), and the additional one is appended to the list.
Only one ellipsis is allowed in the list.
Same for the featureWriters.
Fontmake will also be updated to allow passing --filter='...' or --feature-writer='...' CLI options to use this feature.
anthrotype
commented
2 years ago
Currently the
filtersandfeatureWritersparameters always override the ones defined in the UFO lib.plist, and it's impossible to extend instead of replace these, e.g. inserting some additional filter or writer either before or after.This PR allows to pass a special value
...(the actualEllipsissingleton, not the str literal '...') in both these lists, which acts as a placeholder to signal one wants to extend the list of predefined filters/writers.E.g.:
The ellipsis is replaced by the custom filters defined in the UFO lib (if any), and the additional one is appended to the list. Only one ellipsis is allowed in the list. Same for the featureWriters.
Fontmake will also be updated to allow passing --filter='...' or --feature-writer='...' CLI options to use this feature.
Part of fixing https://github.com/googlefonts/fontmake/issues/872