<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Jan 21, 2015 at 11:11 AM, Guido van Rossum <span dir="ltr"><<a href="mailto:guido@python.org" target="_blank">guido@python.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">So I believe you are saying, suppose I have a function that takes an integer argument and then JSON-encodes it and sends it to some server that requires a JSON int. Now suppose you are adding type hints to your code, and you add ": int" to the parameter under discussion. And now suppose you have a faulty caller which calls this function with the argument set to True. This program will type-check correctly, because True is a bool which is a subclass of int, but it will run incorrectly, because (under this assumption) True will be converted to a JSON true value, which the server rejects.</div></div></div></blockquote><div><br></div><div>This sounds like it may benefit from the issue under discussion for Cython -- a way to specify an int only, and not allow subclasses.</div><div><br></div><div>Though I suppose in this case, you may want to allow other subclasses, just not that one.</div><div><br></div><div>This hypothetical code could also to a cast/conversion to int anyway, which is pretty much how you'd do it with duck typing and no type checking.</div><div><br></div><div>-Chris</div></div><div><br></div>-- <br><div class="gmail_signature"><br>Christopher Barker, Ph.D.<br>Oceanographer<br><br>Emergency Response Division<br>NOAA/NOS/OR&R (206) 526-6959 voice<br>7600 Sand Point Way NE (206) 526-6329 fax<br>Seattle, WA 98115 (206) 526-6317 main reception<br><br><a href="mailto:Chris.Barker@noaa.gov" target="_blank">Chris.Barker@noaa.gov</a></div>
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