AST design

Guide to create abstract syntax tree

create terminals at the latest node possible when it changes type

• e.g. IdentifierReference(Expression) to Identifier to IDENTIFIER, IdentifierReference(Expression) will be the last point we create a node

create a node if the node is changing type

• e.g. AssignmentExpression(Expression) to ExpressionStatement(Statement)

avoid creating a new node if what it is doing is just type casting

• e.g. from NewExpression to MemberExpression

... more?