<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="">Thoughts inline.<div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 16, 2017, at 4:26 PM, Ben Cohen 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=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><p style="box-sizing: border-box; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255); margin-top: 0px !important;" class="">Hi swift-evolution,</p><p style="box-sizing: border-box; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255); margin-top: 0px !important;" class="">Following up on Ted’s post regarding the opening up of stage 2, I’m starting a thread to discuss improvements to the <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary</code> type.</p><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class="">Here is a list of commonly requested changes/enhancements to <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary</code>, all of which would probably be appropriate to put together into a single evolution proposal:</p><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box;" class=""><code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">init</code> from/<code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">merge</code> in a <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Sequence</code> of <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Key/Value</code> pairs (already raised as SE-100: <a href="https://github.com/apple/swift-evolution/blob/master/proposals/0100-add-sequence-based-init-and-merge-to-dictionary.md" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(64, 120, 192); text-decoration: none;" class="">https://github.com/apple/swift-evolution/blob/master/proposals/0100-add-sequence-based-init-and-merge-to-dictionary.md</a>).</li></ul></div></div></blockquote><div>+1. I have wanted this since Swift 1.</div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">make the <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Values</code> view collection a <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">MutableCollection</code> (as in this PR: <a href="https://github.com/apple/swift-evolution/pull/555" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(64, 120, 192); text-decoration: none;" class="">https://github.com/apple/swift-evolution/pull/555</a>).</li></ul></div></div></blockquote>I think Nate’s proposal covers this case well.</div><div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Add a defaulting <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">subscript</code> <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">get</code> (e.g. <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">counts[key, default: 0] += 1</code> or <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">grouped(key, default:[]].append(value)</code>).</li></ul></div></div></blockquote>I am indifferent to this. I am happy using ??. I guess it could be slightly more efficient because it avoids wrapping and unwrapping the optional.</div><div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Add a group by-like init to create a <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary<K,[V]></code> from a sequence of <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">V</code> and a closure <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">(V)->K</code>.</li></ul></div></div></blockquote>+1. I would use this.</div><div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Add <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary.filter</code> to return a <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary</code>.</li></ul></div></div></blockquote>+1.</div><div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Add <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary.mapValues</code> to return a <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary</code> (can be more efficiently implemented than composition as the storage layout remains the same).</li></ul></div></div></blockquote><div>+1000. I have also been asking for this since the beginning. I built my own version (and use it frequently), but as you say, the standard library can do it much more efficiently.</div><div><br class=""></div><div>I would also like to see an in-place version as well.</div><div><br class=""></div><div>One design detail. Even though it is only mapping the values, I would like it to pass the key to the closure as well. It occasionally figures in to the mapping logic.</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Add <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">capacity</code> property and <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">reserveCapacity()</code> method.</li></ul></div></div></blockquote><div>+0.5. I could see it being useful occasionally.</div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Have <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary.removeAtIndex</code> return the <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Index</code> of the next entry.</li></ul></div></div></blockquote><div>No opinion on this.</div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">(once we have conditional conformance) Make dictionaries with <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Equatable</code> values <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Equatable</code>.</li></ul></div></div></blockquote><div>+1</div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class="">Please reply here with any comments or questions on the above list, or any additions you believe are important that are missing from it.</p></div></div></blockquote><div>I would also like to see a version of map which returns a dictionary and handles key collisions:</div><div><br class=""></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>let newDict = myDict.map(collision: {k,v1,v2 in v2}) { (k,v) in ... }</div><div><br class=""></div><div>The collision parameter would take a throwing closure and handle the case of a key conflict (by returning the value to use, throwing, or trapping). It would have a default value so that it would only have to be specified if a different behavior was desired. </div><div><br class=""></div><div>In advanced cases, the collision could be used to accumulate values together. Because of this, I would actually like to see this on *collection* (not just dictionary). The map closure is handed each element of the sequence (which in the case of dictionary is a key/value tuple), and expects a return value of a key/value tuple. The collision block is called when a key is returned which has already been used to figure out what value to use. This might choose a winner, or it could act like reduce, building a value from the components.</div><div><br class=""></div><div>As a concrete example of what this allows, I could take in an array of words/strings [“apple”, “aardvark”, …] and then do the following to get a count of how many words start with each letter:</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>let letterFrequency = words.map(collision:{$1+$2}) { (String($0.characters.first ?? “”) ,1)}</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>print(letterFrequency[“a”]) //number of words starting with “a"</div><div><br class=""></div><div>I am ok using a term other than ‘map' if that is easier on the compiler, but I would like this functionality. At the simple end, it allows map functionality for both keys and values. At the advanced end, it acts as a categorizing reduce over a sequence/collection.</div><div><br class=""></div><div>You can even trivially implement the proposed groupBy with it (this is on Collection, but you could do an init on dict the same way):</div><div><br class=""></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>func grouped<K>(by categorizer: (Element)->K ) -> [K:Element] {</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>return self.map(collision:{$1+$2}) {(categorizer($0), [$0])}</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>}</div><div><br class=""></div><div><br class=""></div><div>Thanks,</div><div>Jon</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class="">All methods added to the standard library increase complexity, so need a strong justification to reduce the risk of API sprawl. When requesting additions/modifications, please keep the following questions in mind:</p><ol style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box;" class="">Is the suggested addition a common operation that many would find useful? Can it be flexible enough to cover different needs?</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Will it encourage good practice? Might it be misused or encourage anti-patterns?</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Can the operation be composed simply from existing std lib features? Is that composition intuitive/readable? </li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Is writing the equivalent by hand hard to get right? Are there common correctness traps that this addition would help avoid?</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Is writing the equivalent by hand hard to make efficient? Are there common performance traps that this addition would help avoid?</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Might a native implementation be able to execute more efficiently, by accessing internals, than the equivalent implementation using public APIs?</li></ol><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class="">As he has already written up SE-100 and another <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary</code> proposal, Nate Cook has kindly offered to collate a new omnibus proposal for <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Dictionary</code>, which will then get pitched here.</p><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class="">I will send another email about enhancements to <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Sequence</code>/<code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 11.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">Collection</code> algorithms shortly.</p><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255);" class="">Thanks!</p><div style="box-sizing: border-box; margin-top: 0px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255); margin-bottom: 0px !important;" class="">Ben</div><div style="box-sizing: border-box; margin-top: 0px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255); margin-bottom: 0px !important;" class=""><br class=""></div><div style="box-sizing: border-box; margin-top: 0px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 14px; background-color: rgb(255, 255, 255); margin-bottom: 0px !important;" class=""><br class=""></div></div>_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""></div></blockquote></div><br class=""></div></body></html>