property_name : PropertyName
IndicPositionalCategory
IndicPositionalCategory :: # (opaque)
Unicode Indic_Positional_Category (InPC) from
IndicPositionalCategory.txt. Its notional positions classify characters;
they do not prescribe final glyph placement.
of_scalar : Scalar -> Value
alias_count : Value -> U8
Value : Value
PropertyName : { short : Str, long : Str }
Run : { range : TextRange, value : Value }
AliasError : [UnknownAlias]