<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Some simple questions:</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">Say Tuples are deprecated and removed from the language: </div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">How would you go about pattern matching on multiple values in the same switch statement? </div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">What about pattern bindings for multiple values?</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">When a function that takes more than one argument in a particular parameter list is partially applied, how will I apply the needed tuple of arguments to complete the call later?</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">There is a lot of overlap if you view them simply as data structures, but there is also a lot the language itself does with them that has to be worked out if they're going to be replaced.</div><div id="AppleMailSignature"><br>~Robert Widmann</div><div><br>2017/01/07 19:17、Freak Show via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> のメッセージ:<br><br></div><blockquote type="cite"><div><div class="">FWIW, I searched the previous proposals for any kind of mention of tuple and found nothing so forgive me if this has been discussed before. </div><div class=""><br class=""></div>Swift currently has 5 ways to represent multi-values.<div class=""><br class=""></div><div class="">Classes, structs, arrays, dictionaries, and tuples.</div><div class=""><br class=""></div><div class="">Of these, classes are well established and unique in that they support inheritance and often have identity. </div><div class=""><br class=""></div><div class="">The others, however, are primarily used as value types in their immutable incarnations. Consider a desire to pass around a cartesian coordinate. The following representations are available:</div><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="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> x = </span><span style="font-variant-ligatures: no-common-ligatures; color: #d12f1b" class="">"x"</span></div><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="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> y = </span><span style="font-variant-ligatures: no-common-ligatures; color: #d12f1b" class="">"y"</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; min-height: 13px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><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="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> XY { </span><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> x: </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: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</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; min-height: 13px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><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="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> txy = (x: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">1</span><span style="font-variant-ligatures: no-common-ligatures" class="">, y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class="">) </span><span style="font-variant-ligatures: no-common-ligatures; color: #008400" class="">// (.0 1,.1 2)</span></div><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="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> sxy = </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">XY</span><span style="font-variant-ligatures: no-common-ligatures" class="">(x: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">1</span><span style="font-variant-ligatures: no-common-ligatures" class="">, y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ) </span><span style="font-variant-ligatures: no-common-ligatures; color: #008400" class="">// XY</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> dxy = [ </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">x</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">1</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">y</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">// ["y": 2, "x": 1]</span></div><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="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> axy = [ </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">1</span><span style="font-variant-ligatures: no-common-ligatures" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ] </span><span style="font-variant-ligatures: no-common-ligatures; color: #008400" class="">// [1,2]</span></div><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="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> taxy = ( </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">1</span><span style="font-variant-ligatures: no-common-ligatures" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ) </span><span style="color: rgb(0, 132, 0);" class="">// (.0 1,.1 2)</span></div></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class="">Their print strings are in the comment to the right - that could be a source of a whole other proposal. </div><div class=""><br class=""></div><div class="">A developer might choose from any one of these to represent a Point. They all represent the same information. Yet the syntax required to make use of them is annoyingly different.</div><div class=""><br class=""></div><div class="">Consider the tuple with named fields which is being used as a sort of anonymous ad hoc struct:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(79, 129, 135);" class=""><div style="margin: 0px; line-height: normal; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">txy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.x </span><span style="font-variant-ligatures: no-common-ligatures" class="">// 1</span></div><div style="margin: 0px; line-height: normal; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">txy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">// 1</span></div><div style="margin: 0px; line-height: normal; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">txy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">x</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div><div style="margin: 0px; line-height: normal; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">txy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div></div></div><div class="">vs the declared struct</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(79, 129, 135);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">sxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures" class="">x</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">sxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">//error</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">sxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">x</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">//error</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">sxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">//error</span></div></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">vs the dictionary</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">dxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.x </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">dxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">dxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">x</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">// 1</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">dxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">and then we have the tuple with unnamed fields</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">taxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">// 1</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">taxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class="">vs the array</div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">axy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">axy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">[</span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">0</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">] </span><span style="font-variant-ligatures: no-common-ligatures" class="">// 1</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">It is worth observing that, to the programmer the variable sxy is indistinguishable from txy. They represent the same informtion, they are accessed in the exactly the same way. They are completely equivalent. However this fails:</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">sxy = txy // error</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class="">this succeeds (which may or may not be good depending on context and coincidence):</div><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: rgb(186, 45, 162);" class="">var</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> txy = (x: </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(39, 42, 216);" class="">1</span><span style="font-variant-ligatures: no-common-ligatures;" class="">, y: </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(39, 42, 216);" class="">2</span><span style="font-variant-ligatures: no-common-ligatures;" class="">)</span></div></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="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> txy2 = ( x: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class="">, y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">3</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; color: rgb(79, 129, 135);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">txy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures" class="">txy2 // OK</span></div></div><div class=""><br class=""></div><div class="">but this fails (which I think is a good thing)</div><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="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> XY { </span><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> x: </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: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</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; color: #ba2da2" class="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> XY2 { </span><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> x: </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: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div></div></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" 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="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> sxy2 = </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">XY2</span><span style="font-variant-ligatures: no-common-ligatures" class="">(x: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class="">, y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">3</span><span style="font-variant-ligatures: no-common-ligatures" class="">)</span></div></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; color: #ba2da2" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> sxy = </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">XY</span><span style="font-variant-ligatures: no-common-ligatures" class="">(x: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">1</span><span style="font-variant-ligatures: no-common-ligatures" class="">, y: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class=""> )</span></div></div><div class=""><span style="font-variant-ligatures: no-common-ligatures; color: #008400" class=""><br class=""></span></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">sxy</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">=</span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">sxy2</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">// error</span></div></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div style="margin: 0px; line-height: normal;" class="">The point of this comparison is to point out that the anonymous type generating tuple is a) superfluous and b) a source of confusion and gratuitous complexity. It assumes the role at times of immutable arrays, anonymous structs, and immutable dictionaries depending on context and we already have all of those things. </div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Proposal:</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">1) Eliminate the tuple as a first level concept.</div><div style="margin: 0px; line-height: normal;" class="">2) Replace tuples that have named fields with structs or immutable dictionaries.</div><div style="margin: 0px; line-height: normal;" class="">3) Replace tuples without named fields with immutable arrays.</div><div style="margin: 0px; line-height: normal;" class="">4) Disallow tuple expressions that mix named and unnamed fields - IOW - this is an abomination:</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" 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="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> mixed = (z: </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">1</span><span style="font-variant-ligatures: no-common-ligatures" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: #272ad8" class="">2</span><span style="font-variant-ligatures: no-common-ligatures" class="">)</span></div></div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">If nothing else in this proposal resonates at all - that should be adopted.</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">5) Unify field access syntax. Pick one or allow both on everything (similar to javascript).</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">FWIW, this isn't hard to do already in Objective C. It is possible to make use of default handlers to allow dict.field access on NSDictionary with a very small amount of code. Javascript also supports both dictionary oriented access (obj['field']) and dot notation (obj.field) so there is precedent for this kind of flexibility. </div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">6) Unify iteration over all the fields of all the kinds of things that have fields. In this case, tuples are kind of like sequenced collections that have been lobotomized. </div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Conclusion</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">There is a lot of overlap among the concepts of structs, immutable dictionaries, immutable arrays and tuples. They are a source of gratuitous complexity in the language and a likely ongoing source of frustration as developers choose different, equivalent, but incompatible representations for common types of data. My primary fear is that anonymous tuples will tend to phase out named struct types and an important source of documentation of intent will be lost.</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">It should also be noted that I am not a compiler or VM writer and I don't give a fig how the language does things at the implementation level and this is primarily a conceptual/syntactic proposal. The goal is to make consuming data types predictable and simple and eliminate gratuitous complexity at the conceptual level through generalization of special cases.</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Thanks for reading. Still reading the process document to figure out how to make this "official".</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>swift-evolution mailing list</span><br><span><a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a></span><br><span><a href="https://lists.swift.org/mailman/listinfo/swift-evolution">https://lists.swift.org/mailman/listinfo/swift-evolution</a></span><br></div></blockquote></body></html>