12.4. Pure FunctionsΒΆ
A pure function does not produce side effects. It communicates with the
calling program only through parameters (which it does not modify) and a return
value. Here is the doubleStuff
function from the previous section written as a pure function.
To use the pure function version of double_stuff
to modify things
,
you would assign the return value back to things
.
Once again, codelens helps us to see the actual references and objects as they are passed and returned.