<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 3, 2017, at 4:58 PM, Jun Wu <<a href="mailto:quark@fb.com" class="">quark@fb.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">Excerpts from Jun Wu's message of 2017-06-03 13:54:18 -0700:</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">Excerpts from Augie Fackler's message of 2017-06-03 16:25:52 -0400:<br class=""><blockquote type="cite" class="">I like where you're headed with this, but I think I'd rather have<br class="">classes with an efficient way to produce a set implement toset<br class="">themselves and leave the default implementation as set(self) so we can<br class="">avoid the spooky action at a distance implied by this hasattr().<br class=""></blockquote><br class="">The problem is the lack of ability to customize "set(smartset)" logic in the<br class="">Python language. "set" will always treat "smartset" as an iterable, which<br class="">makes the operation O(N log N) even if we have O(1) fast path.<br class=""><br class="">Between syntactic simplicity and ability to have fast code path, I want to<br class="">choose the latter.<br class=""><br class="">For "hasattr", do you mean we might need to do hasattr(x, 'toset')? That<br class="">looks like a sign of poorly designed APIs (sometimes return a smartset,<br class="">sometimes return a set, so you never know what "x" is). It shouldn't happen<br class="">in a clean codebase.<br class=""></blockquote><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">Sorry. I misunderstood the whole paragraph. I'll move "toset" from</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">"abstractsmartset" to subclasses.</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""></div></blockquote><div><br class=""></div><div>You should probably still have a toset() on abstractsmartset if you intend for it to be a mandatory part of the interface (which I recommend, per Liskov), but have it either do set(self) or (probably better) raise NotImplementedError.</div><br class=""><blockquote type="cite" class=""><div class=""><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">Good advice by the way!</span></div></blockquote></div><br class=""><div class="">Thanks! Glad you like it. :)</div></body></html>