<div dir="ltr"><div class="gmail_extra">All right, I have gone through and formulated a set of characters to serve as the core of our operator symbols. I started with [:Sm:] and removed blocks and subheaders which are not clearly useful as operators (though may be reincorporated selectively in the future). Then I added the rest of the Arrows block, as well as punctuation symbols that are “operator-like”.</div><div class="gmail_extra"><br></div><div class="gmail_extra">In particular, I kept Swift’s existing ASCII operators, and all of Swift’s Latin-1 operators except for currency signs and the copyright and registered trademark symbols. I also kept most of Swift’s existing General Punctuation operators.</div><div class="gmail_extra"><br></div><div class="gmail_extra"><a href="http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%5B%3ASm%3A%5D%0D%0A%0D%0A-%5Cp%7BBlock%3DSuperscripts+And+Subscripts%7D%0D%0A-%5Cp%7BBlock%3DMiscellaneous+Technical%7D%0D%0A-%5Cp%7BBlock%3DGeometric+Shapes%7D%0D%0A-%5Cp%7BBlock%3DMiscellaneous+Symbols%7D%0D%0A-%5Cp%7BBlock%3DAlphabetic+Presentation+Forms%7D%0D%0A-%5Cp%7BBlock%3DSmall+Form+Variants%7D%0D%0A-%5Cp%7BBlock%3DHalfwidth+And+Fullwidth+Forms%7D%0D%0A-%5Cp%7BBlock%3DMathematical+Alphanumeric+Symbols%7D%0D%0A-%5Cp%7BBlock%3DArabic+Mathematical+Alphabetic+Symbols%7D%0D%0A-%5Cp%7Bsubhead%3DVariant+letterforms+and+symbols%7D%0D%0A-%5Cp%7Bsubhead%3DLetterlike+symbol%7D%0D%0A%0D%0A%5Cp%7BBlock%3DArrows%7D%0D%0A%5B%2F+%3D+%5C-+%2B+%21+*+%25+%3C+%3E+%5C%26+%7C+%5C%5E+~+%3F%5D%0D%0A%5B%C2%A1+%C2%A2+%C2%A3+%C2%A4+%C2%A5+%C2%A6+%C2%A7+%C2%A9+%C2%AB+%C2%AC+%C2%AE+%C2%B0+%C2%B1+%C2%B6+%C2%BB+%C2%BF%5D+-+%5B%C2%A2+%C2%A3+%C2%A4+%C2%A5+%C2%A9+%C2%AE%5D%0D%0A%5Cp%7Bsubhead%3DGeneral+punctuation%7D+-+%5BU%2B203F+U%2B2040+U%2B2045+U%2B2046+U%2B2054%5D%0D%0A%5Cp%7Bsubhead%3DDouble+punctuation+for+vertical+text%7D%0D%0A%5Cp%7Bsubhead%3DArchaic+punctuation%7D+-+%5BU%2B2E31+U%2B2E33+U%2B2E34+U%2B2E3F%5D%0D%0AU%2B214B%5D&amp;g=&amp;i=">The end result is a set of 1,020 operator characters</a>, which <a href="http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%2F+%3D+%5C-+%2B+%21+*+%25+%3C+%3E+%5C%26+%7C+%5C%5E+~+%3F%0D%0AU%2B00A1+-+U%2B00A7%0D%0AU%2B00A9+U%2B00AB+U%2B00AC+U%2B00AE%0D%0AU%2B00B0+-+U%2B00B1%0D%0AU%2B00B6+U%2B00BB+U%2B00BF+U%2B00D7+U%2B00F7%0D%0AU%2B2016+-+U%2B2017%0D%0AU%2B2020+-+U%2B2027%0D%0AU%2B2030+-+U%2B203E%0D%0AU%2B2041+-+U%2B2053%0D%0AU%2B2055+-+U%2B205E%0D%0AU%2B2190+-+U%2B23FF%0D%0AU%2B2500+-+U%2B2775%0D%0AU%2B2794+-+U%2B2BFF%0D%0AU%2B2E00+-+U%2B2E7F%0D%0AU%2B3001+-+U%2B3003%0D%0AU%2B3008+-+U%2B3030%5D%0D%0A%0D%0A-%5B%5B%3ASm%3A%5D%0D%0A-%5Cp%7BBlock%3DSuperscripts+And+Subscripts%7D%0D%0A-%5Cp%7BBlock%3DMiscellaneous+Technical%7D%0D%0A-%5Cp%7BBlock%3DGeometric+Shapes%7D%0D%0A-%5Cp%7BBlock%3DMiscellaneous+Symbols%7D%0D%0A-%5Cp%7BBlock%3DAlphabetic+Presentation+Forms%7D%0D%0A-%5Cp%7BBlock%3DSmall+Form+Variants%7D%0D%0A-%5Cp%7BBlock%3DHalfwidth+And+Fullwidth+Forms%7D%0D%0A-%5Cp%7BBlock%3DMathematical+Alphanumeric+Symbols%7D%0D%0A-%5Cp%7BBlock%3DArabic+Mathematical+Alphabetic+Symbols%7D%0D%0A-%5Cp%7Bsubhead%3DVariant+letterforms+and+symbols%7D%0D%0A-%5Cp%7Bsubhead%3DLetterlike+symbol%7D%0D%0A%5Cp%7BBlock%3DArrows%7D%0D%0A%5B%2F+%3D+%5C-+%2B+%21+*+%25+%3C+%3E+%5C%26+%7C+%5C%5E+~+%3F%5D%0D%0A%5B%C2%A1+%C2%A2+%C2%A3+%C2%A4+%C2%A5+%C2%A6+%C2%A7+%C2%A9+%C2%AB+%C2%AC+%C2%AE+%C2%B0+%C2%B1+%C2%B6+%C2%BB+%C2%BF%5D+-+%5B%C2%A2+%C2%A3+%C2%A4+%C2%A5+%C2%A9+%C2%AE%5D%0D%0A%5Cp%7Bsubhead%3DGeneral+punctuation%7D+-+%5BU%2B203F+U%2B2040+U%2B2045+U%2B2046+U%2B2054%5D%0D%0A%5Cp%7Bsubhead%3DDouble+punctuation+for+vertical+text%7D%0D%0A%5Cp%7Bsubhead%3DArchaic+punctuation%7D+-+%5BU%2B2E31+U%2B2E33+U%2B2E34+U%2B2E3F%5D%0D%0AU%2B214B%5D&amp;g=&amp;i=">removes 1,628 symbols</a> from <a href="http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%2F+%3D+%5C-+%2B+%21+*+%25+%3C+%3E+%5C%26+%7C+%5C%5E+~+%3F%0D%0AU%2B00A1+-+U%2B00A7%0D%0AU%2B00A9+U%2B00AB+U%2B00AC+U%2B00AE%0D%0AU%2B00B0+-+U%2B00B1%0D%0AU%2B00B6+U%2B00BB+U%2B00BF+U%2B00D7+U%2B00F7%0D%0AU%2B2016+-+U%2B2017%0D%0AU%2B2020+-+U%2B2027%0D%0AU%2B2030+-+U%2B203E%0D%0AU%2B2041+-+U%2B2053%0D%0AU%2B2055+-+U%2B205E%0D%0AU%2B2190+-+U%2B23FF%0D%0AU%2B2500+-+U%2B2775%0D%0AU%2B2794+-+U%2B2BFF%0D%0AU%2B2E00+-+U%2B2E7F%0D%0AU%2B3001+-+U%2B3003%0D%0AU%2B3008+-+U%2B3030%5D&amp;g=&amp;i=">Swift’s existing operator set</a> and <a href="http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%5B%3ASm%3A%5D%0D%0A-%5Cp%7BBlock%3DSuperscripts+And+Subscripts%7D%0D%0A-%5Cp%7BBlock%3DMiscellaneous+Technical%7D%0D%0A-%5Cp%7BBlock%3DGeometric+Shapes%7D%0D%0A-%5Cp%7BBlock%3DMiscellaneous+Symbols%7D%0D%0A-%5Cp%7BBlock%3DAlphabetic+Presentation+Forms%7D%0D%0A-%5Cp%7BBlock%3DSmall+Form+Variants%7D%0D%0A-%5Cp%7BBlock%3DHalfwidth+And+Fullwidth+Forms%7D%0D%0A-%5Cp%7BBlock%3DMathematical+Alphanumeric+Symbols%7D%0D%0A-%5Cp%7BBlock%3DArabic+Mathematical+Alphabetic+Symbols%7D%0D%0A-%5Cp%7Bsubhead%3DVariant+letterforms+and+symbols%7D%0D%0A-%5Cp%7Bsubhead%3DLetterlike+symbol%7D%0D%0A%5Cp%7BBlock%3DArrows%7D%0D%0A%5B%2F+%3D+%5C-+%2B+%21+*+%25+%3C+%3E+%5C%26+%7C+%5C%5E+~+%3F%5D%0D%0A%5B%C2%A1+%C2%A2+%C2%A3+%C2%A4+%C2%A5+%C2%A6+%C2%A7+%C2%A9+%C2%AB+%C2%AC+%C2%AE+%C2%B0+%C2%B1+%C2%B6+%C2%BB+%C2%BF%5D+-+%5B%C2%A2+%C2%A3+%C2%A4+%C2%A5+%C2%A9+%C2%AE%5D%0D%0A%5Cp%7Bsubhead%3DGeneral+punctuation%7D+-+%5BU%2B203F+U%2B2040+U%2B2045+U%2B2046+U%2B2054%5D%0D%0A%5Cp%7Bsubhead%3DDouble+punctuation+for+vertical+text%7D%0D%0A%5Cp%7Bsubhead%3DArchaic+punctuation%7D+-+%5BU%2B2E31+U%2B2E33+U%2B2E34+U%2B2E3F%5D%0D%0AU%2B214B%5D%0D%0A%0D%0A-%5B%2F+%3D+%5C-+%2B+%21+*+%25+%3C+%3E+%5C%26+%7C+%5C%5E+~+%3F%0D%0AU%2B00A1+-+U%2B00A7%0D%0AU%2B00A9+U%2B00AB+U%2B00AC+U%2B00AE%0D%0AU%2B00B0+-+U%2B00B1%0D%0AU%2B00B6+U%2B00BB+U%2B00BF+U%2B00D7+U%2B00F7%0D%0AU%2B2016+-+U%2B2017%0D%0AU%2B2020+-+U%2B2027%0D%0AU%2B2030+-+U%2B203E%0D%0AU%2B2041+-+U%2B2053%0D%0AU%2B2055+-+U%2B205E%0D%0AU%2B2190+-+U%2B23FF%0D%0AU%2B2500+-+U%2B2775%0D%0AU%2B2794+-+U%2B2BFF%0D%0AU%2B2E00+-+U%2B2E7F%0D%0AU%2B3001+-+U%2B3003%0D%0AU%2B3008+-+U%2B3030%5D&amp;g=&amp;i=">adds just 4 new ones</a> (⅀ ؆ ؇ ⅋). I left out the “Full Stop” character, to be dealt with by whatever rules we decide upon for dots in operators.</div><div class="gmail_extra"><br></div><div class="gmail_extra">Here is the classification of the 1,020 characters I have identified as operators:</div><div class="gmail_extra"><div class="gmail_extra"><br></div><div class="gmail_extra"><div class="gmail_extra">[[:Sm:]</div><div class="gmail_extra">-\p{Block=Superscripts And Subscripts}</div><div class="gmail_extra">-\p{Block=Miscellaneous Technical}</div><div class="gmail_extra">-\p{Block=Geometric Shapes}</div><div class="gmail_extra">-\p{Block=Miscellaneous Symbols}</div><div class="gmail_extra">-\p{Block=Alphabetic Presentation Forms}</div><div class="gmail_extra">-\p{Block=Small Form Variants}</div><div class="gmail_extra">-\p{Block=Halfwidth And Fullwidth Forms}</div><div class="gmail_extra">-\p{Block=Mathematical Alphanumeric Symbols}</div><div class="gmail_extra">-\p{Block=Arabic Mathematical Alphabetic Symbols}</div><div class="gmail_extra">-\p{subhead=Variant letterforms and symbols}</div><div class="gmail_extra">-\p{subhead=Letterlike symbol}</div><div class="gmail_extra">\p{Block=Arrows}<br></div><div class="gmail_extra">[/ = \- + ! * % &lt; &gt; \&amp; | \^ ~ ?]</div><div class="gmail_extra">[¡ ¢ £ ¤ ¥ ¦ § © « ¬ ® ° ± ¶ » ¿] - [¢ £ ¤ ¥ © ®]</div><div class="gmail_extra">\p{subhead=General punctuation} - [U+203F U+2040 U+2045 U+2046 U+2054]</div><div class="gmail_extra">\p{subhead=Double punctuation for vertical text}</div><div class="gmail_extra">\p{subhead=Archaic punctuation} - [U+2E31 U+2E33 U+2E34 U+2E3F]</div><div class="gmail_extra">U+214B]</div></div></div><div class="gmail_extra"><br></div><div class="gmail_extra">Additionally, I think it is worthwhile to consider including the “Drafting symbols” subheader and most of the “Miscellaneous technical” subheader. This would add <a href="http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5Cp%7Bsubhead%3DDrafting+symbols%7D%0D%0A%5Cp%7Bsubhead%3DMiscellaneous+technical%7D%0D%0A-%5BU%2B23E8%5D%5D&amp;g=&amp;i=">34 more operator characters</a>.</div><div class="gmail_extra"><br></div><div class="gmail_extra">I did not consider <a href="http://unicode.org/cldr/utility/list-unicodeset.jsp?a=U%2B0300+-+U%2B036F%0D%0AU%2B1DC0+-+U%2B1DFF%0D%0AU%2B20D0+-+U%2B20FF%0D%0AU%2BFE00+-+U%2BFE0F%0D%0AU%2BFE20+-+U%2BFE2F%0D%0AU%2BE0100+-+U%2BE01EF&amp;g=&amp;i=">non-head operator characters</a>, which are predominantly combining marks and variant selectors, and should probably stay essentially as they are. Also, I kept the empty set and infinity sign as operators, though we may want to change that.<br></div><div class="gmail_extra"><br></div><div class="gmail_extra">There are a lot more symbols that could potentially become operators (eg. shapes, currency signs, APL, etc.). However in light of the prevailing view that we should start conservatively and add more in the future, I believe this set of 1,020 characters is a good place to begin.</div><div class="gmail_extra"><br></div><div class="gmail_extra">Nevin</div></div>