Er... no. No it absolutely wouldn't block until end-of-input.
If list comprehensions were being used to precompute the output and the whole list printed from (what you seem to be thinking of) then perhaps yes, but any of:
for x in sys.stdin:
...
or
[... for x in sys.stdin]
(where ... is print(func(x)) as per the post)
as per the GP post will print response strings as the input comes in.
