<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=""><meta http-equiv="content-type" content="text/html; charset=utf-8" class=""><div dir="auto" class=""><br class=""><div class="">On Oct 2, 2017, at 09:14, Xiaodi Wu <<a href="mailto:xiaodi.wu@gmail.com" class="">xiaodi.wu@gmail.com</a>> wrote:<br class=""><br class=""></div><blockquote type="cite" class="">What is your use case for this?<br class=""><br class=""><div class="gmail_quote"><div dir="ltr" class="">On Mon, Oct 2, 2017 at 10:56 David Sweeris 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"><div dir="auto" class=""><br class=""><div class="">On Oct 1, 2017, at 22:01, Chris Lattner via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class=""></div><blockquote type="cite" class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Oct 1, 2017, at 9:26 PM, Kenny Leung via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>> wrote:</div><br class="m_8138847825612054131Apple-interchange-newline"><div class=""><div style="word-wrap:break-word" class=""><div class="">Hi All.</div><div class=""><br class=""></div><div class="">I’d like to help as well. I have fun with operators.</div><div class=""><br class=""></div><div class="">There is also the issue of code security with invisible unicode characters and characters that look exactly alike.</div></div></div></blockquote><div class=""><br class=""></div><div class="">Unless there is a compelling reason to add them, I think we should ban invisible characters. What is the harm of characters that look alike?</div></div></blockquote><br class=""></div><div dir="auto" class=""><div class="">Especially if people want to use the character in question as both an identifier and an operator: We can make the character an identifier and its lookalike an operator (or the other way around).</div></div>
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</blockquote><div class=""><br class=""></div><div class="">Off the top of my head...</div><div class="">In calculus, “𝖽” (MATHEMATICAL SANS-SERIF SMALL D) would be a fine substitute for "d" in “𝖽y/𝖽x” ("the derivative of y(x) with respect to x").</div><div class="">In statistics, we could use "𝖢" (MATHEMATICAL SANS-SERIF CAPITAL C), as in "5𝖢3" to mimic the "<span style="font-size: 8px; -webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; vertical-align: -1px; -webkit-font-kerning: none;" class=""><sub class="">5</sub></span><span style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; line-height: normal; -webkit-font-kerning: none;" class="">C</span><span style="font-size: 8px; -webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; vertical-align: -1px; -webkit-font-kerning: none;" class=""><sub class="">3</sub></span>" notation ("5 choose 3"). And although not strictly an issue of identifiers vs operators, “！” (FULLWIDTH EXCLAMATION MARK) would be an ok substitution (that extra space on the right looks funny) for "!" in “4！” ("4 factorial").</div><div class=""><br class=""></div><div class="">I'm sure there are other examples from math/science/<insert any "symbology"-heavy DSL here>, but “d” in particular is one that I’ve wanted for a while since Swift classifies "∂" (the partial derivative operator) as an operator rather than an identifier, making it impossible to use a consistent syntax between normal derivatives and partial derivatives (normal derivatives are "d(y)/d(x)", whereas partial derivatives get to drop the parens "∂y/∂x")</div><div class=""><br class=""></div><div class="">- Dave Sweeris</div></div></body></html>