https://www.cs.cornell.edu/~asampson/blog/flattening.html https://www.cs.cornell.edu/~asampson/blog/flattening.html Flattened AST. Not conceptually different,

https://www.cs.cornell.edu/~asampson/blog/flattening.html https://www.cs.cornell.edu/~asampson/blog/flattening.html Flattened AST. Not conceptually different, but a much better performance of implementation.