Part of the point of effect systems is precisely to allow HOF's to deal with these "color" differences in a consistent way. Similar to how in Rust, an error re

Part of the point of effect systems is precisely to allow HOF's to deal with these "color" differences in a consistent way. Similar to how in Rust, an error return is modeled as just an instance of some Option<> or Result<> type instead of some bespoke 'exception', so all HOF's can seamlessly manage the 'exceptional' case.