pub fn decode_units(unit_id: u32) -> IsccResult<Vec<MainType>>Expand description
Decode a unit combination index (0–7) to a sorted list of optional MainTypes.
Inverse of encode_units. Decodes the 3-bit bitfield:
bit 0 = Content, bit 1 = Semantic, bit 2 = Meta. Results are returned
in MainType discriminant order (Meta, Semantic, Content) so they are
automatically sorted.