<div dir="ltr">> <span style="font-size:12.8px">Array already has init(repeating:count:) that puts the responsibility of choosing the default value at the call site. If someone were writing a generic algorithm around this, then why not just propagate that responsibility out to its call site as well? That way, the algorithm isn't making any assumptions about what the "default" value is or even if one exists,</span><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Because encapsulation. There's a reason NSObject has a default initializer.</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Dec 26, 2016 at 12:10 PM, Tony Allevato via swift-evolution <span dir="ltr"><<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><span class="">On Mon, Dec 26, 2016 at 11:57 AM David Sweeris via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:<br></span><div class="gmail_quote"><span class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto" class="m_7676584481830758401gmail_msg"><div class="m_7676584481830758401gmail_msg"><br class="m_7676584481830758401gmail_msg"></div><div class="m_7676584481830758401gmail_msg">On Dec 26, 2016, at 11:35, Tony Allevato <<a href="mailto:allevato@google.com" class="m_7676584481830758401gmail_msg" target="_blank">allevato@google.com</a>> wrote:<br class="m_7676584481830758401gmail_msg"><br class="m_7676584481830758401gmail_msg"></div><blockquote type="cite" class="m_7676584481830758401gmail_msg"><div class="m_7676584481830758401gmail_msg">Mathematically, identities are associated with (type, operation) pairs, not types alone.<br class="m_7676584481830758401gmail_msg"><br class="m_7676584481830758401gmail_msg">This conversation has put me in the column of "numeric types shouldn't have default initializers at all", personally.
</div></blockquote><br class="m_7676584481830758401gmail_msg"></div><div dir="auto" class="m_7676584481830758401gmail_msg"><div class="m_7676584481830758401gmail_msg">I'd agree, except sometimes you need a T, <i class="m_7676584481830758401gmail_msg">any</i> T, for when you want to create a "pre-sized" array for stuffing results into by index:</div><div class="m_7676584481830758401gmail_msg">for i in ... {</div><div class="m_7676584481830758401gmail_msg"> a[i] = ...</div><div class="m_7676584481830758401gmail_msg">}</div><div class="m_7676584481830758401gmail_msg">Simply saying "var a =[T](); a.reserveCapacity()" doesn't cut it because it'll still crash if you try to store anything in a[i] without somehow putting at least i+1 elements in the array first.</div></div></blockquote><div><br></div></span><div>Array already has init(repeating:count:) that puts the responsibility of choosing the default value at the call site. If someone were writing a generic algorithm around this, then why not just propagate that responsibility out to its call site as well? That way, the algorithm isn't making any assumptions about what the "default" value is or even if one exists, and it doesn't impose additional requirements on the element type. For example, the user could get the default from a static factory method, an instance method on another object, or something else entirely.</div><span class=""><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto" class="m_7676584481830758401gmail_msg"><div class="m_7676584481830758401gmail_msg"><br class="m_7676584481830758401gmail_msg"></div><div class="m_7676584481830758401gmail_msg">- Dave Sweeris</div></div>______________________________<wbr>_________________<br class="m_7676584481830758401gmail_msg">
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