<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=""><div class="">yes, exactly Doug... the properties at type level are part of the interface and their types can be inferred, so i don't see the difference with function argument types.</div><div class=""><br class=""></div><div class="">i just find it really bulky when writing something like this:</div><div class=""><br class=""></div><div class="">func doSomething(thing, withManager: SomethingManager = SomethingManager()) {</div><div class=""> // prepare the thing</div><div class="">}</div><div class=""><br class=""></div><div class="">I think this meets the API guidelines for "omitting needless words"</div><div class=""><br class=""></div><div class="">And it should be invalid syntax to expect the type to be inferred for a generic argument (i.e. no change from current behaviour)</div><div class=""><br class=""></div>
<br class=""><div><blockquote type="cite" class=""><div class="">On 11 May 2016, at 04:53, Douglas Gregor <<a href="mailto:dgregor@apple.com" class="">dgregor@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><span style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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="">Sent from my iPhone</span><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><blockquote type="cite" style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class="">On May 10, 2016, at 8:33 PM, Chris Lattner via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class=""><blockquote type="cite" class="">On May 10, 2016, at 3:02 AM, Sam Dods via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class="">I propose that function argument types could be omitted in the same way as variable and property argument types are omitted when they are set at point of definition.<br class=""><br class="">At present the type of properties and variables can be inferred as below:<br class=""><br class="">class EvolutionManager {<br class="">let proposalManager = ProposalManager() // type is inferred<br class=""><br class="">func proposeTopic(topic: String) {<br class=""> let evolution = Evolution(topic: topic) // type is inferred<br class=""> proposalManager.proposeEvolution(evolution)<br class="">}<br class="">}<br class=""><br class="">However, function arguments cannot be inferred, as below:<br class=""><br class="">class EvolutionManager {<br class="">func proposeEvolution(evolution: Evolution, proposalManager = ProposalManager()) { // compiler error, cannot infer type<br class=""></blockquote><br class="">We have a pretty strict rule here: types are allowed to be inferred in implementations, but not interfaces. This is important for efficient compilation, encourages people to think about their API interfaces, and somewhat reduces the damage when they don’t.<br class=""></blockquote><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><span style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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="">We broke this rule when we started allowing properties at type and module scope to have inferred types. I was moderately opposed to it at the time, but we have it, we're going to keep it, and this suggestion for inferring parameter types from default arguments seems to fit in the same category.<span class="Apple-converted-space"> </span></span><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><span style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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="">That said, I have implementation concerns: we don't want the expression type checker to be involved when figuring out the type of a generic function, so we would need to define this in a way that doesn't affect the computation of generic signatures for a function. Probably, such types just aren't involved in inferring generic constraints.<span class="Apple-converted-space"> </span></span><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><span style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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=""> - Doug</span><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><br style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><blockquote type="cite" style="font-family: Apercu; font-size: 12px; font-style: normal; font-variant-caps: 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;" class=""><br class="">_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a></blockquote></div></blockquote></div><br class=""></body></html>