<div dir="ltr"><div>I, too, think that this is too special a case for a dedicated syntax but so far I prefer:</div><div><br></div><div>  <span style="font-family:monospace,monospace">x None-or y</span></div><div class="gmail_extra"><br></div><div class="gmail_extra">The meaning is more clear to me. <span style="font-family:monospace,monospace">None-or</span> is like regular or except that <span style="font-family:monospace,monospace">y</span> is evaluated only if <span style="font-family:monospace,monospace">x</span> is <span style="font-family:monospace,monospace">None</span>.<br></div><div class="gmail_extra"><span class="gmail-_Tgc"> </span></div><div class="gmail_extra"><div class="gmail_quote"><br></div><div class="gmail_quote">On Thu, Nov 30, 2017 at 2:35 AM, MRAB <span dir="ltr"><<a href="mailto:python@mrabarnett.plus.com" target="_blank">python@mrabarnett.plus.com</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"><span class="gmail-">On 2017-11-29 21:27, Greg Ewing wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Nick Coghlan wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
What about more English-like syntax:<br>
<br>
X or else Y<br>
</blockquote>
<br>
The problem with constructs like this is that they look like they<br>
should mean the same thing as "X or Y".<br>
</blockquote>
<br>
How about:<br>
<br>
     x otherwise y<br>
<br>
It looks different enough from "or" that you're not going<br>
to accidentally read it that way when skimming.<br>
<br>
The meaning is something you'll have to learn if you don't<br>
know, but at least it's a word that can be googled for.<br>
<br>
</blockquote></span>
It has the disadvantage that it's quite long. How about "alt" (abbreviation for "alternatively"):<br>
<br>
    x alt y<div class="gmail-HOEnZb"><div class="gmail-h5"><br>
______________________________<wbr>_________________<br>
Python-ideas mailing list<br>
<a href="mailto:Python-ideas@python.org" target="_blank">Python-ideas@python.org</a><br>
<a href="https://mail.python.org/mailman/listinfo/python-ideas" rel="noreferrer" target="_blank">https://mail.python.org/mailma<wbr>n/listinfo/python-ideas</a><br>
Code of Conduct: <a href="http://python.org/psf/codeofconduct/" rel="noreferrer" target="_blank">http://python.org/psf/codeofco<wbr>nduct/</a><br>
</div></div></blockquote></div><br></div></div>