The Graph signature changes are needed for future function work, and it
also fits in nicely with the need for storing the value pointer for each
function node. These are used to later extract values during the Output
stage.
Sam deserves all of the credit for realizing both of these points and
convincing me to make the change! It worked out great, cheers!
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>