<div dir="ltr">Sorry, I sent this accidentally as private reply, then tried to fix it on phone. The latter produced horrible formatting. Please just read this version.<div><br><div class="gmail_quote"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span class="">On Sat, Sep 10, 2016 at 4:10 PM, 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:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">So you're offering `NoneCoalesce(x).bar` as less-ugly alternative to<br>
`x?.bar`... Color me unconvinced.<br></blockquote><div><br></div></span><div>No, I'm offering a more realistic use pattern:</div><div><br></div></div></div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><font face="monospace, monospace">for x in get_stuff():</font></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><font face="monospace, monospace"> x = NoneCoalesce(x)</font></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><font face="monospace, monospace"> # ... bunch of stuff with x ...</font></div><div><span style="font-family:monospace,monospace"> # ... more stuff with nested keys or attributes ...</span></div><div><div class="gmail_extra"><div class="gmail_quote"></div></div></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><font face="monospace, monospace"> x2 = x.foo</font></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><font face="monospace, monospace"> x3 = x.bar.baz[x2]</font></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><font face="monospace, monospace"> x4 = x(x.val)</font></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><font face="monospace, monospace"> result = x3(x4)</font></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div> <br></div></div></div></blockquote><div class="gmail_extra"><div class="gmail_quote"><div>As a less ugly alternative in the fairly uncommon case that you want None coalescing as the behavior of getting attributes, keys, call values, etc. that may or may not be available (AND where you don't want to wrap all of those access patterns in one try/except block).</div><div><br></div><div>In contrast, the ugly version of even this pretty simple toy code with the hypothetical syntax would be:</div><div><br></div><div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><font face="monospace, monospace">for x in get_stuff():</font></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><span style="font-family:monospace,monospace"> # ... bunch of stuff with x ...</span><br></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div><span style="font-family:monospace,monospace"> # ... more stuff with nested keys or attributes ...</span></div><div><div class="gmail_extra"><div class="gmail_quote"></div></div></div></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><font face="monospace, monospace"> x2 = x?.foo</font></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><font face="monospace, monospace"> x3 = x?.bar?.baz?[x2]</font></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><font face="monospace, monospace"> x4 = x?(x?.val)</font></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><font face="monospace, monospace"> result = x3?(x4)</font></div></div></blockquote><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"></div></div></blockquote></div><div><br></div><div>This second case looks absolutely awful to me. And real world uses, if implemented, would quickly get much worse than that.</div><div><br></div><div>Yours, David...</div></div><div><div class="h5"><div><br></div>-- <br><div>Keeping medicines from the bloodstreams of the sick; food <br>from the bellies of the hungry; books from the hands of the <br>uneducated; technology from the underdeveloped; and putting <br>advocates of freedom in prisons. Intellectual property is<br>to the 21st century what the slave trade was to the 16th.<br></div>
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</div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature">Keeping medicines from the bloodstreams of the sick; food <br>from the bellies of the hungry; books from the hands of the <br>uneducated; technology from the underdeveloped; and putting <br>advocates of freedom in prisons. Intellectual property is<br>to the 21st century what the slave trade was to the 16th.<br></div>
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