Exercise: Rewriting with Result
In this exercise we’re revisiting the expression evaluator exercise that we did
in day 2. Our initial solution ignores a possible error case: Dividing by zero!
Rewrite eval
to instead use idiomatic error handling to handle this error case
and return an error when it occurs. We provide a simple DivideByZeroError
type
to use as the error type for eval
.
Speaker Notes
This slide and its sub-slides should take about 20 minutes.
- The starting code here isn’t exactly the same as the previous exercise’s solution: We’ve added in an explicit panic to show students where the error case is. Point this out if students get confused.