<div dir="ltr">Chris, <div><br></div><div>IIRC, by definition a NAN is not equal to itself...</div><div><br></div><div>Dale</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Sep 3, 2014 at 4:11 PM, Chris Muller <span dir="ltr"><<a href="mailto:ma.chris.m@gmail.com" target="_blank">ma.chris.m@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">When could it happen?<br>
<br>
A: With Float nan.<br>
<br>
Float nan == Float nan "true"<br>
<br>
Float nan = Float nan "false"<br>
<br>
It violates what I have long considered an invariant that if a==b, then a=b.<br>
<br>
Real world context: When two DB clients change the same object in the<br>
exact same way, it's not a conflict. If they change it differently,<br>
it is.<br>
<br>
They've both made the same reference to Float nan, but just asking if<br>
they made equivalent changes still reports false. So I have to put in<br>
a complicated special check for NaN first..??<br>
<br>
Okay, I actually wrote: (a==b or: [a=b]) but who would ever write<br>
that or not "simplify it" in teh future if they saw it?<br>
<br>
Comments? Why shouldn't Float nan = Float nan?<br>
<br>
</blockquote></div><br></div>