<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jul 1, 2016, at 10:05 AM, Erica Sadun via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Jul 1, 2016, at 6:12 AM, Björn Forster via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">In <a href="https://github.com/apple/swift-evolution/blob/master/proposals/0067-floating-point-protocols.md" style="font-family:"Helvetica Neue",Helvetica,"Segoe UI",Arial,freesans,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol";font-size:16px;line-height:25.6px;color:rgb(64,120,192);outline-width:0px;background-color:transparent" class="">SE-0067: Enhanced Floating Point Protocols</a> is stated that pi will be a built in constant from Swift 3 onwards.<div class=""><div style="font-size:12.8px" class="">Is there a specific reason why pi as a constant will be included but not e? e is also ubiquitous in scientific, engineering and economic calculations. I seems odd to me to include pi but then not e as well. Also Python provides both pi and e. Shouldn't Swift provide also at least both pi and e as constants for its floating point types? </div><div style="font-size:12.8px" class="">It is also not nice if different numerical packages for swift will come up all with their own different definitions of e. I think Swift 3 should use the opportunity to get this thing right from the beginning and provided both pi AND e. </div><div style="font-size:12.8px" class=""><br class=""></div><div style="font-size:12.8px" class="">Is there a new proposal necessary to still get e as a built in constant into Swift 3? </div></div></div></div></blockquote><br class=""></div><div class="">I think this thread will answer that question for you:</div><div class=""><a href="http://thread.gmane.org/gmane.comp.lang.swift.evolution/22200/focus=22466" class="">http://thread.gmane.org/gmane.comp.lang.swift.evolution/22200/focus=22466</a></div></div></div></blockquote><div><br class=""></div>That only is about tau, which is a much more controversial operator. Unfortunately, I wasn’t able to find the discussion of pi or E in the archives (but neither pi nor e are very searchable)</div><div><br class=""></div><div>In general, the line for mathematical functions appears to have been set pretty high for inclusion in SE-0067, focusing instead on IEEE 754 capabilities and general design/naming. There are a number of features missing from a standard math library such as the ability to do trigonometric and hyperbolic operations, exponential and logarithmic operations, and so on. I am not sure what criteria determined where this line was drawn. I suspect it was trying to get to a point of just additive changes.</div><div><br class=""></div><div>But for all I know, pi may have been included just so that people didn’t use π in math extension libraries ;-)</div><div><br class=""></div><div>-DW</div><div><br class=""></div></div></body></html>