Lesson 12: Returning from Functions

I’ve missed a small bit about Functions out from these lessons which is crucial to understand what’s happening when using interfaces/methods… and when it comes to writing your own structs.

You can get the result of a function by making sure the last line returns the value you want.

fn MultiplyThese varA varB =
 (
 varA * varB
 )
a = MultiplyThese 10 10

The above code is going to assign a to the result of the MultiplyThese function to the variable a, so 10 * 10, a == 100.

Lets look what adding another line in will do….

fn MultiplyThese varA varB =
 (
 varA * varB
 50
 )
a = MultiplyThese 10 10

The second line of the function is 50 so this is what it will return to us regardless of what varA * varB actually gives us. We can force the function to return the value from the 1st line by using return.

fn MultiplyThese varA varB =
 (
 return varA * varB
 50
 )
a = MultiplyThese 10 10

A second return value will override the first, this is useful for if test/case clauses.

fn MultiplyThese varA varB
 (
 return varA * varB
 if varB == 0 do return 1
 )

You could also make sure the value that is returned is what you want by declaring the local variable at the end of your function.

fn MultiplyThese varA varB
(
   local endResult
   endResult = VarA * VarB
   if varB == 0 do endResult = 1
   endResult
 )

It’s important to understand how functions return values and the scopes of these when using recursive functions, which I’ll explain in another lengthy post.