<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=""><div><blockquote type="cite" class=""><div class=""><div dir="ltr" style="font-family: Helvetica; font-size: 12px; 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 class="gmail_extra"><div class="gmail_quote"><div class="">Anyway, my expectation is that going along this way (i.e. removing all runtime API apart from a necessary minimum)</div><div class="">will give a minor speed-up as compared to PEP 560 at the cost of a breaking change (even for small number of developers).</div></div></div></div></div></blockquote><div><br class=""></div><div>I don't think the change will be breaking: usage of this class will be entirely voluntarily and does not replace typing.Generic</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" style="font-family: Helvetica; font-size: 12px; 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 class="gmail_extra"><div class="gmail_quote"><div class="">PEP 560 already gives overhead of 80% as compared to normal classes in worst case scenario</div><div class="">(empty body with a single generic base). This is actually less than for ABCs (they can give up to 120% in worst case scenario).<br class=""></div></div></div></div></div></blockquote><div><br class=""></div><div>GenericMeta inherits from ABCMeta. Do you mean that it will be removed after 560 lands?</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" style="font-family: Helvetica; font-size: 12px; 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 class="gmail_extra"><div class="gmail_quote"><div class=""></div><div class="">Moreover, performance is not a single motivation for PEP 560, there are other arguments such as metaclass conflicts which will</div><div class="">not be solved without the machinery proposed by the PEP.<br class=""></div></div></div></div></div></blockquote><div><br class=""></div><div>Perhaps you can consider designing Generic / GenericMeta in a way that will allow end user to create GenericStub-alike class without much trouble?</div></div></body></html>