<html><head><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="">I still absolutely think the best proposal for this is to add a Fraction type to the standard library with easy conversions to and from all the numeric types.<div class=""><br class=""></div><div class="">Your precision is only limited by the size of IntMax, and you can do whatever operations you want without losing precision. There’s a great package for it by Jaden Geller on GitHub here:</div><div class=""><br class=""></div><div class=""><a href="https://github.com/jadengeller/fractional" class="">https://github.com/jadengeller/fractional</a></div><div class=""><br class=""></div><div class="">— Harlan</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Mar 21, 2016, at 7:04 AM, Haravikk 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=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px;" class=""><br class="Apple-interchange-newline">On 20 Mar 2016, at 17:54, Rainer Brockerhoff via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class="">On 3/20/16 14:43, Andrey Tarantsov via swift-evolution wrote:<br class=""><blockquote type="cite" class="">I have no stake in this proposal, except for:<br class=""><br class=""><blockquote type="cite" class="">I suggest, therefore, that this acceptance be indicated by an<br class="">annotation to the literal; a form such as ~0.1 might be easiest to<span class="Apple-converted-space"> </span><br class="">read and implement, as the prefix ~ operator currently has no<br class="">meaning for a floating-point value.<br class=""></blockquote><br class="">Whatever you do, don't touch the literals! I specify NSTimeIntervals<br class="">of 0.1, 0.2, 0.25 etc all over the place, and I couldn't care less if<br class="">my animations are one femtosecond off.<br class=""><br class="">Don't pollute everyone's apps with tildes just because there's a<br class="">niche that needs to care about precision loss.<br class=""></blockquote><br class="">Yes, I'm now agreeing that the ideal solution is to leave the whole<br class="">binary floating-point mess alone and write a reasonable `Decimal` type.<br class="">I'll update my text accordingly when I find time.<br class=""></blockquote><br style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px; float: none; display: inline !important;" class="">The alternative would be to make the Decimal type the default anywhere that Double or Float isn’t used; while this may be overkill, it shouldn’t impact performance of most applications. At this point the less-safe but higher performance types would be opt-in by either specifying the type or using the tilde operator.</span><br style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px; float: none; display: inline !important;" class="">This could actually expand the definition of the ± on constants to instead imply “pick the type that can represent this”, so 0.1±0.01 would pick Double, Float or Decimal as appropriate, favouring the higher performance types only if they can represent that value without exceeding the allowable error.</span><br style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; 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-stroke-width: 0px; float: none; display: inline !important;" class="">It is a tricky area though, Swift does have a goal of safety so it may be worth pushing a change that promotes that, even if it means that means a few changes to get maximum performance back; this could be partly avoided by the way the change is handled though, providing warnings where the intent is ambiguous, or assuming performance over safety for existing code?</span><br style="font-family: Helvetica; font-size: 12px; 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; 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