<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=""><blockquote type="cite" class="">On Feb 8, 2016, at 9:24 PM, Jordan Rose <<a href="mailto:jordan_rose@apple.com" class="">jordan_rose@apple.com</a>> wrote:<br class=""></blockquote><div><blockquote type="cite" class=""><br class="Apple-interchange-newline"><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">The library author still needs to document what the default behavior is<span class="Apple-converted-space"> </span></span><i class="" style="font-family: Helvetica; font-size: 12px; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;">anyway,</i><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class=""> so that users know if they want it, and they need to be very careful in changing existing programs, so that they don't break anyone who was depending on the old behavior</span></div></blockquote><br class=""></div><div>It seems to me that using a default parameter means you don’t care about its value. If you explicitly want a certain value, and especially if you’re *depending* on a certain value, it would be best to supply that value explicitly. Using the default is saying “eh, do whatever you think is best."</div><div><br class=""></div><div><blockquote type="cite" class="">and they need to make sure that anybody who supplied the same value explicitly really does <i class="">not</i> want the new behavior.</blockquote></div><div><br class=""></div><div>It seems to me that if you explicitly provide a value to a parameter which has a default, it would appear that you want that value. Else, why go to the trouble of explicitly providing it?</div><div><br class=""></div><div>Charles</div><div><br class=""></div></body></html>