Pretty Printing Scala Case Classes Like A Tree - scala

Question

I am looking to build a tool that when an expression is input into it, it would produce a step by step evaluation proof and render it as a tree. I will also do the same thing for type checking tree.
Here are several examples of expressions and their equivalent ASTs:
1 + 1 + 1 = Plus(Plus(Num(1), Num(1)), Num(1))
\x:int.x = Lambda(x,IntTy,Var(x))
if 1 + x == 2 then 90 + 1 else 99 = IfThenElse(Eq(Plus(Num(1),Var(x)),Num(2)),Plus(Num(90),Num(1)),Num(99))
I want to output a nicely formatted step-by-step execution tree. Taking an example 1:
Num(1) | {eval res.} Num(1) | {eval res.}
--------------------------------- --------------------
Plus(Num(1), Num(1)) | {eval res.} Num(1) | {eval res.}
--------------------------------------------------------------
Plus(Plus(Num(1), Num(1)), Num(1)) | {eval res.}
At each recursive step, I want to embed evaluation result into {eval res.}
In the future, I will also want to add capability of the user being able to do small-step evaluation. So, when we start at the bottom, when a button is clicked or something like that, the Plus(Num(1), Num(1)) | {eval res.} appears but not Num(1) | {eval res.} because left hand side recursion did not bottom out yet and it continues.
Here are a few examples of such proof trees:
https://i.imgur.com/8hv5Mwb.png
And type checking derivation: https://i.imgur.com/J3RvoYT.png
I want to print out a tree in a vertical manner like that. Having looked through related questions, I have not found anyone attempting this.