Getting a simple AST working in Python

Hi all -

For a very long time, I've had problems understanding abstract syntax trees and how to implement them for interpreters or compilers.
I don't have a problem with lexing (creating tokens) but when it comes to arranging said tokens into an AST I hit a brick wall.

I'm aware that there is this site here which looks at ASTs - https://ruslanspivak.com/lsbasi-part7/ - but the code there is under the MIT license and I want the code I put together to be "public domain" - this means that I can't use that code.

Anyway - this is what I've come up with so far -

Code:

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#  ast.py 

#  This code is released to the public domain
#  under the Unlicense.
#  "Share and enjoy......"  :) 

#  expr : term ((PLUS|MINUS) term)*
#  term : factor ((MUL|DIV) factor)*
#  factor : INTEGER | LPAREN expr RPAREN


# Simple node-type for numbers and operators
class node()
  def __init__(self, ntype, nvalue):
      self.ntype = ntype
      self.nvalue = nvalue
     
  def __repr__(self):
      print self.ntype, self.nvalue     


# Binary node-type for number OP number. 
class binnode()
  def __init__(self, ntype, op, left, right):
      self.ntype = ntype
      self.op = op
      self.left = left
      self.right = right
     
  def __repr__(self):
      print self.ntype, self.op, self.left, self.right

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So, any help to develop this further is much appreciated!
Many thanks - bye for now -
- t

For a program you need data structures and algorithm. You've made a start at some data structures but you are lacking an algorithm. Choose an algorithm https://en.wikipedia.org/wiki/Catego...ing_algorithms then have a go at coding it.

Quote:

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Originally Posted by spjackson

For a program you need data structures and algorithm. You've made a start at some data structures but you are lacking an algorithm. Choose an algorithm https://en.wikipedia.org/wiki/Catego...ing_algorithms then have a go at coding it.

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Hi spjackson - thanks for your reply!

Ok - I'll check out that link and will go from there.
Thanks again, bye for now -

- t.