type Rule
import ezsys@0.1.0.0/src/str.bend as Strimport Base
218# a run of code points `lo` to `hi`, every `step`-th one from `lo`, mapped
219# in order onto the code points from `to`
220type Rule is Data:
221 Rule{lo: U32, hi: U32, step: U32, to: U32}