Suggestions for lecture on patterns and exceptions w06: Mathcable, Nothing, Union types, etc

[bjornregnell]

• Add slide on the scala type hierarchy including Matchable and Nothing
• Show pitfall that if then without else gives type Unit and potentially lost values
• Improve example on typed patterns, find and example that is more practically justified
• Show that thrown exceptions has type nothing
• Show that union types can be a simpler (but more primitive) alternative to subtyping / basetype to acheive a more precise type than Matchable
• Show a more complete translation of enum Color { case Red, Black } into a trait -- case class expansion.
• Explain Exception Error Throwable, Consider explaining this in carola example

[bjornregnell]

https://stackoverflow.com/questions/2274102/difference-between-using-throwable-and-exception-in-a-try-catch