Hands-On Design Patterns and Best Practices with Julia

Implementing conditional logic in functional pipes

Since the logical flow is quite linear, how do we deal with conditional logic?

Suppose we want to determine the hotness of top stories by checking the average score against a threshold. If the average score is higher than 100, then it would be considered high; otherwise, it would be considered low. So, literally, we need an if-statement that determines what to execute next.

We can use dynamic dispatch to solve this problem. We are going to build this function from the bottom-up, as follows.

1. Create the hotness function, which determines the hotness of the Hacker News site by score. It returns an instance of the Val{:high} or Val{:low} parametric type. The built-in Val data type is a convenient ...