My collegue suggested me to write a visitor pattern to navigate the AST. Can anyone tell me more how would I start writing it?
As far as I understand, each Node in AST would have
5 + 2 * 444
Wikipedia has a great overview of how the Visitor pattern works, although the sample implementation that they use is in Java. You can easily port that to Python, though, no?
Basically, you want to implement a mechanism for double dispatch. Each node in your AST would need to implement an
accept() method (NOT a
visit() method). The method takes, as an argument, a visitor object. In the implementation of this
accept() method, you call a
visit() method of the visitor object (there will be one for each AST node type; in Java, you'll use parameter overloading, in Python I suppose you can use different
visit_*() methods). The correct visitor will then be dispatched with the correct Node type as argument.