x = foo()
bar(x.a: x.b:)
Functions can return data. So say, a=5, then to get the value of 5 out, all you have to do is call the function a.
Edit: I'm assuming foo() here returns an object with members "a" and "b". An example of such a function-object would be:
foo = [] { ret( [a=5, b=10] ) }