ANTLR What is simpliest way to realize python like indent-depending grammar?

Question

I am trying realize python like indent-depending grammar.

Source example:

ABC QWE
  CDE EFG
  EFG CDE
    ABC 
  QWE ZXC

As i see,

Answer 1

There is an open-source library antlr-denter for ANTLR v4 that helps parse indents and dedents for you. Check out its README for how to use it.

Since it is a library, rather than code snippets to copy-and-paste into your grammar, its indentation-handling can be updated separately from the rest of your grammar.