<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="">IMO, we should have a `Random` or `RandomGenerator` interface and the stdlib can provide a `SystemRandom` that wraps arc4*/random(), and maybe a cryptographically secure one too (MT19937?).<div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures" class=""> RandomGenerator {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> uniform</span><span style="font-variant-ligatures: no-common-ligatures" class="">() -> <font color="#4f8187" class="">Int</font></span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> uniform</span><span style="font-variant-ligatures: no-common-ligatures" class="">() -> <font color="#4f8187" class="">Double</font></span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">func</span><span style="font-variant-ligatures: no-common-ligatures" class=""> uniformBytes(count: </span><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span><span style="font-variant-ligatures: no-common-ligatures" class="">) -> </span><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Data</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; min-height: 13px;" class=""><br class=""></div><div class="">Then we could add things like, e.g. a protocol extension to generate normally distributed numbers (<a href="https://en.wikipedia.org/wiki/Box–Muller_transform" class="">https://en.wikipedia.org/wiki/Box%E2%80%93Muller_transform</a>).<br class=""><div class=""><br class=""></div><div class=""><span style="font-family: Menlo; font-size: 11px; font-variant-ligatures: no-common-ligatures; color: rgb(186, 45, 162);" class="">extension</span><span style="font-family: Menlo; font-size: 11px; font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="color: rgb(79, 129, 135); font-family: Menlo; font-size: 11px; font-variant-ligatures: no-common-ligatures;" class="">RandomGenerator</span><span style="font-family: Menlo; font-size: 11px; font-variant-ligatures: no-common-ligatures;" class=""> {</span></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(186, 45, 162);" class="">func</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> normal<T: </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(112, 61, 170);" class="">FloatingPoint</span><span style="font-variant-ligatures: no-common-ligatures;" class="">>() -> (</span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(79, 129, 135);" class="">T</span><span style="font-variant-ligatures: no-common-ligatures;" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(79, 129, 135);" class="">T</span><span style="font-variant-ligatures: no-common-ligatures;" class="">) {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(0, 132, 0);" class="">// ...</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""> }</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">}</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""><br class=""></span></div><div><blockquote type="cite" class=""><div class="">On Sep 8, 2017, at 10:08 AM, Shawn Erickson 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="">It would be nice to leverage range support instead of a start and end value IMHO.</div></blockquote><blockquote type="cite" class=""><div class=""><div class="gmail_quote"><div dir="ltr" class="">On Fri, Sep 8, 2017 at 9:52 AM Alejandro Alonso via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Hello swift evolution, I would like to propose a unified approach to `random()` in Swift. I have a simple implementation here <a href="https://gist.github.com/Azoy/5d294148c8b97d20b96ee64f434bb4f5" target="_blank" class="">https://gist.github.com/Azoy/5d294148c8b97d20b96ee64f434bb4f5</a>.
This implementation is a simple wrapper over existing random functions so existing code bases will not be affected. Also, this approach introduces a new random feature for Linux users that give them access to upper bounds, as well as a lower bound for both
Glibc and Darwin users. This change would be implemented within Foundation.
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<div class="">I believe this simple change could have a very positive impact on new developers learning Swift and experienced developers being able to write single random declarations.</div>
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<div class="">I’d like to hear about your ideas on this proposal, or any implementation changes if need be.</div>
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<div class="">- Alejando</div>
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