Ah yes, I see what you mean:
class Test():
x = 1
print (x) # Prints 1
print([x+i for i in range(1,3)]) # NameError (x)
Anyway, I apologise for posting to Python-Dev on was a known issue, and
turned out to be more me asking for help with development with Python,
rather than development of Python. (My original use case was a
scripting language that could contain embedded Python code). Thanks to
Nick for his original answer.
Rob Cliffe
On 11/06/2018 23:31, Eric Fahlgren wrote:
On Mon, Jun 11, 2018 at 3:10 PM Rob Cliffe via Python-Dev
<python-dev@python.org <mailto:python-dev@python.org>> wrote:
Skip, I think you have misunderstood the point I was making. It was
not whether the loop variable should leak out of a list
comprehension.
Rather, it was whether a local variable should, so to speak, "leak
into"
a list comprehension. And the answer is: it depends on whether
the code
is executed normally, or via exec/eval. Example:
def Test():
x = 1
print([x+i for i in range(1,3)]) # Prints [2,3]
exec('print([x+i for i in range(1,3)])') # Raises NameError (x)
Test()
I (at least at first) found the difference in behaviour surprising.
Change 'def' to 'class' and run it again. You'll be even more
surprised.
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