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22.11.17 15:25, Ivan Levkivskyi пише:

I think this is indeed a problem.. For me the biggest surprise was that \`yield\` inside a comprehension does not turn a surrounding function into comprehension, see also
https://stackoverflow.com/questions/29334054/why-am-i-getting-different-results-when-using-a-list-comprehension-with-coroutin

In fact there is a b.p.o. issue for this https://bugs.python.org/issue10544, it is assigned to me since July, but I was focused on other things recently.
My plan was to restore the Python 2 semantics while still avoiding the leak of comprehension variable to the enclosing scope (the initial reason of introducing auxiliary "\_make\_list" function IIUC).
So that:

1) g = \[(yield i) for i in range(3)\] outside a function will be a SyntaxError (yield outside a function)
2) g = \[(yield i) for i in range(3)\] inside a function will turn that enclosing function into generator.
3) accessing i after g = \[(yield i) for i in range(3)\] will give a NameError: name 'i' is not defined

If you have time to work on this, then I will be glad if you take care of this issue, you can re-assign it.

I have the same plan. I know how implement this for comprehensions, but the tricky question is what to do with generator expressions? Ideally

result = \[expr for i in iterable\]

and

result = list(expr for i in iterable)

should have the same semantic. I.e. if expr is "(yield i)", this should turn the enclosing function into a generator function, and fill the list with values passed to the generator's .send(). I have no idea how implement this.