One downside with the code on the right is that it’s not obvious where the different functions might be called from. In the example on the left, we know that we’re not, say, adding toppings to a pizza that we’ve already baked. If we notice a bug in the topping adding function on the right, we might get tempted to reason about adding toppings as a general process that needs to handle all kinds of situations when in practice is doesn’t.
When you have single use functions like this it’s good to limit the scope of the function using whatever language features are available so that you can more easily reason about where it’s being called from
One way to make it obvious which function can be called at which state is to use different type. Like UnbackedPizza and CookedPizza, and the bake function takes the former and returns the later.
One downside with the code on the right is that it’s not obvious where the different functions might be called from. In the example on the left, we know that we’re not, say, adding toppings to a pizza that we’ve already baked. If we notice a bug in the topping adding function on the right, we might get tempted to reason about adding toppings as a general process that needs to handle all kinds of situations when in practice is doesn’t.
When you have single use functions like this it’s good to limit the scope of the function using whatever language features are available so that you can more easily reason about where it’s being called from
One way to make it obvious which function can be called at which state is to use different type. Like
UnbackedPizzaandCookedPizza, and thebakefunction takes the former and returns the later.