Hi today during a lecture I was quite surprised to see the name of the AST variables. There is no easy way to see that a variable is a position in the text or a subtree. Example RBValueNode subclass: #RBArrayNode instanceVariableNames: 'left right statements periods' classVariableNames: '' category: 'AST-Core-Nodes' RBValueNode subclass: #RBBlockNode instanceVariableNames: 'left right colons arguments bar body scope' classVariableNames: '' category: 'AST-Core-Nodes' Annoying because you have always to think (yes I know I'm stupid not knowing by heart the tree structure) to know if you get a tree under your fingers. We can definitively better in terms of code habilitability. We cleaned the visitor and since then the code is much much much better. I would do the following RBValueNode subclass: #RBArrayNode instanceVariableNames: 'leftParenthesisPosition rightParenthesisPosition statements periodsPosition' classVariableNames: '' category: 'AST-Core-Nodes' I would be also ok with RBValueNode subclass: #RBArrayNode instanceVariableNames: 'leftPosition rightPosition statements periodsPosition' classVariableNames: '' category: 'AST-Core-Nodes' RBValueNode subclass: #RBBlockNode instanceVariableNames: 'leftPosition rightPosition colonsPosition arguments barPosition body scope' classVariableNames: '' category: 'AST-Core-Nodes'