Returns the schema for the horizons data.table carried by a
PedonRecord: an ordered named list mapping column names to
their R type ("numeric" or "character"). Adding a new
attribute means editing this single function.
Returns the schema for the horizons data.table carried by a
PedonRecord: an ordered named list mapping column names to
their R type ("numeric" or "character"). Adding a new
attribute means editing this single function.