[Python-ideas] Revised^4 PEP on yield-from

[Greg Ewing]

Antoine Pitrou wrote:

> Greg, I find this qualification ("obfuscation") a bit offensive...

Sorry, I don't mean that personally. The fact is that it
does look obfuscated to my eyes, and I'd be surprised
if I were the only person who thinks so.

> (and, actually, I don't understand how "yield from" helps for a depth-first
> traversal. Could you post an example of it?)

Traversing a binary tree with a non-generator:

   def traverse(node):
     if node:
       process_node(node)
       traverse(node.left)
       traverse(node.right)

Traversing it with a generator:

   def traverse(node):
     if node:
       yield process_node(node)
       yield from traverse(node.left)
       yield from traverse(node.right)

Do you still think an unrolled version would be
equally clear? If so, you have extremely different
tastes from me!

-- 
Greg