<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>They are similar in that they are trying to restrict codeflow based on external conditions. </div><div><br></div><div>Today we have #if os(), #if arch(), plus the ability to set build configuration identifiers. And now there is a new proposal to add #if swift(). </div><div><br></div><div>Keep the #available() and @available() runtime versions. What I'm saying is add #if available() as a compile-time version and generalize the current uses of the #if usages (these could happen migration steps and don't need to necessarily happen all at once). </div><div><br></div><div>When packages start working, it's very easy to see use cases where we want to do the same thing based on package name and version. Build configurations identifiers aren't sufficient for it (version comparison, for instance). So instead needing to propose another construct, #if package(), is there a way to generalize the pattern we are already seeing that could still fit in the scope of this proposal? I think so. </div><div><br><div>Sent from my iPhone</div></div><div><br>On Jan 15, 2016, at 3:35 PM, Jordan Rose <<a href="mailto:jordan_rose@apple.com">jordan_rose@apple.com</a>> wrote:<br><br></div><blockquote type="cite"><div><meta http-equiv="Content-Type" content="text/html charset=utf-8"><div class="">I disagree that these constructs are similar. #available and @available are inherently <i class="">runtime</i> queries, whereas checking the version of Swift is a <i class="">compile-time</i> query. An app ships with code for <i class="">both</i> branches of "if #available".</div><div class=""><br class=""></div><div class="">Jordan</div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On Jan 15, 2016, at 10:49, David Owens II 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=""><div class="" 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;">I think the proposal addresses a need that we have with Swift, but I think the proposal introduces yet-another-special case solution.</div><div class="" 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;"><br class=""></div><div class="" 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;">There is already a construct that nearly serves this purpose. I’d rather see those constructs bolstered and unified.</div><div class="" 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;"><br class=""></div><div class="" 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;">Previous feedback:</div><div class="" 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;"><br class=""></div><div class="" 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;"><div class="">The <font face="Menlo" class="">@available()</font> and <font face="Menlo" class="">if #available</font> constructs are not sufficient as they fall under the same limitations that your proposal addresses: they <i class="">require</i> that the non-valid branch not be parsed. For example, an API that has changes with a new language feature, such as variadic generic arguments, would not be able to be defined.</div><div class=""><br class=""></div><div class="">If we look at the grammar, I don’t see why the grammar for “availability-argument” couldn’t look like this:</div><div class=""><br class=""></div><div class=""><font face="Menlo" class=""><i class=""> availability-argument: (platform-name | language-name | package-name) version.</i></font></div><div class=""><section class="section" style="padding: 0px; margin: 30px 0px 0px; font-size: 10px;"><div class="syntax-defs" style="border-width: 0px 0px 0px 5px; border-left-style: solid; border-left-color: rgb(233, 233, 233); font-size: 1.4em; margin: 20px 0px; outline: 0px; padding: 0px 0px 0px 15px; vertical-align: baseline; line-height: 20.299999237060547px;"><p class="syntax-defs-name" style="border: 0px; font-size: 0.63em; margin: 0px 0px 8px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); letter-spacing: 2px; text-transform: uppercase;">GRAMMAR OF AN AVAILABILITY CONDITION</p><div class="syntax-defs-group" style="font-family: Helvetica, Arial, sans-serif; border: 0px; margin: 0px 0px 12px; outline: 0px; padding: 0px; vertical-align: baseline;"><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/swift/grammar/availability-condition" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">availability-condition </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">#available</code><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">(</code><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/availability-arguments" data-renderer-version="2" data-id="//apple_ref/swift/grammar/availability-arguments" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">availability-arguments</a></span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">)</code></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/swift/grammar/availability-arguments" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">availability-arguments </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><span class="alternative" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; display: inline;"><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/availability-argument" data-renderer-version="2" data-id="//apple_ref/swift/grammar/availability-argument" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">availability-argument</a></span> </span><span class="alternative" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; display: inline;"> <span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/availability-argument" data-renderer-version="2" data-id="//apple_ref/swift/grammar/availability-argument" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">availability-argument</a></span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">,</code><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/availability-arguments" data-renderer-version="2" data-id="//apple_ref/swift/grammar/availability-arguments" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">availability-arguments</a></span></span></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/swift/grammar/availability-argument" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">availability-argument </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/platform-name" data-renderer-version="2" data-id="//apple_ref/swift/grammar/platform-name" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">platform-name</a></span><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/platform-version" data-renderer-version="2" data-id="//apple_ref/swift/grammar/platform-version" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">platform-version</a></span></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_734" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">availability-argument </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">*</code></div></div><div class="syntax-defs-group" style="font-family: Helvetica, Arial, sans-serif; border: 0px; margin: 0px 0px 12px; outline: 0px; padding: 0px; vertical-align: baseline;"><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/swift/grammar/platform-name" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">platform-name </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><span class="alternative" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; display: inline;"><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">iOS</code> </span><span class="alternative" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; display: inline;"> <code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">iOSApplicationExtension</code></span></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_736" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">platform-name </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><span class="alternative" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; display: inline;"><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">OSX</code> </span><span class="alternative" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; display: inline;"> <code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">OSXApplicationExtension</code></span></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_737" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">platform-name </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">watchOS</code></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/swift/grammar/platform-version" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">platform-version </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/swift/grammar/decimal-digits" data-renderer-version="2" data-id="//apple_ref/swift/grammar/decimal-digits" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">decimal-digits</a></span></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_739" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">platform-version </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/swift/grammar/decimal-digits" data-renderer-version="2" data-id="//apple_ref/swift/grammar/decimal-digits" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">decimal-digits</a></span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">.</code><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/swift/grammar/decimal-digits" data-renderer-version="2" data-id="//apple_ref/swift/grammar/decimal-digits" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">decimal-digits</a></span></div><div class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_740" class="" style="border: 0px; margin: -85px 0px 0px; outline: 0px; padding: 85px 0px 0px; vertical-align: baseline; display: block; width: 0px; height: 0px; color: rgb(0, 136, 204);"></a><span class="syntax-def-name" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(128, 128, 128); font-style: italic;">platform-version </span><span class="arrow" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 0px 0px 4px; vertical-align: baseline; color: rgb(128, 128, 128);">→ </span><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/swift/grammar/decimal-digits" data-renderer-version="2" data-id="//apple_ref/swift/grammar/decimal-digits" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">decimal-digits</a></span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">.</code><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/swift/grammar/decimal-digits" data-renderer-version="2" data-id="//apple_ref/swift/grammar/decimal-digits" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">decimal-digits</a></span><code class="literal" style="border: 0px; font-size: 0.86em; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-family: Menlo, monospace; font-weight: 600; word-wrap: break-word;">.</code><span class="syntactic-cat" style="border: 0px; margin: 0px; outline: 0px; padding: 0px 4px; vertical-align: baseline; font-style: italic; word-break: keep-all;"><a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/swift/grammar/decimal-digits" data-renderer-version="2" data-id="//apple_ref/swift/grammar/decimal-digits" class="" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;">decimal-digits</a></span></div></div></div></section><section class="section" style="padding: 0px; margin: 30px 0px 0px; font-family: Helvetica, Arial, sans-serif; font-size: 10px;"></section></div><div class="">I’d further argue that the <font face="Menlo" class="">version</font> argument properly adhere to the semver spec: <a href="http://semver.org/" class="">http://semver.org</a>.</div><div class=""><br class=""></div><div class="">The above change, in addition to the change for the <span class="" style="font-family: Menlo;">if #available<span class="Apple-converted-space"> </span></span>(change to: #<span class="" style="font-family: Menlo;">if available</span>) statement to <i class="">not</i> parse the unavailable path would seem to provide the solution you want to have in addition to the solution that many package developers could use as well.</div><div class=""><br class=""></div><div class="">The nice thing is that this could be done in stages:</div><div class=""><br class=""></div><div class="">1. Add support for the language condition and change #if available to <i class="">not </i>parse the non-valid paths</div><div class="">2. Add support for package names</div><div class="">3. Add support for proper semver versioning.</div><div class=""><br class=""></div><div class="">The only breaking change is #1 as the else-clause would no longer parse the code today. When/if semver was supported, the version could still take the decimal digits while adding semver support.</div></div><div class="" 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;"><br class=""></div><div class="" 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;">-David</div><div class="" 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;"><br class=""></div><br class="" 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;"><div 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;" class=""><blockquote type="cite" class=""><div class="">On Jan 12, 2016, at 10:28 AM, Douglas Gregor <<a href="mailto:dgregor@apple.com" class="">dgregor@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Hello Swift community,<br class=""><br class="">The review of SE-0020 "Swift Language Version Build Configuration” begins now and runs through January 17th. The proposal is available here:<div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span><a href="https://github.com/apple/swift-evolution/blob/master/proposals/0020-if-swift-version.md" class="">https://github.com/apple/swift-evolution/blob/master/proposals/0020-if-swift-version.md</a></div><div class=""><br class="">Reviews are an important part of the Swift evolution process. All reviews should be sent to the swift-evolution mailing list at<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br class=""><br class="">or, if you would like to keep your feedback private, directly to the review manager.<br class=""><br class="">What goes into a review?<br class=""><br class="">The goal of the review process is to improve the proposal under review through constructive criticism and, eventually, determine the direction of Swift. When writing your review, here are some questions you might want to answer in your review:<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* What is your evaluation of the proposal?<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* Is the problem being addressed significant enough to warrant a change to Swift?<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* Does this proposal fit well with the feel and direction of Swift?<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* If you have you used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* How much effort did you put into your review? A glance, a quick reading, or an in-depth study?<br class=""><br class="">More information about the Swift evolution process is available at<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span><a href="https://github.com/apple/swift-evolution/blob/master/process.md" class="">https://github.com/apple/swift-evolution/blob/master/process.md</a><br class=""><br class="">Thank you,<br class="">Doug Gregor<br class="">Review Manager</div><img src="https://u2002410.ct.sendgrid.net/wf/open?upn=nE9rxSXA5G4kxsTVkgv43pXkLx-2B36P-2BPNJufHeY0dgeydoAMuGH3FmVj1d96a885tyuhf2rjbwVDRFWNALHn6UHKUP843lMDYgawB6VOvA73i9Cj-2BcsPL7tvc3cQurMX8tUu4pu3IjfOEm4KMLOZfmCCoKghVPho7jeCs8Phd3sTihTCFMFV-2BH-2FQYEqJpie1zRKqo9aFesrBY-2FmrzfFjbg-3D-3D" alt="" width="1" height="1" border="0" class="" style="height: 1px !important; width: 1px !important; border-width: 0px !important; margin: 0px !important; padding: 0px !important;"></div>_______________________________________________<br class="">swift-evolution-announce mailing list<br class=""><a href="mailto:swift-evolution-announce@swift.org" class="">swift-evolution-announce@swift.org</a><br class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution-announce" class="">https://lists.swift.org/mailman/listinfo/swift-evolution-announce</a><br class=""></div></blockquote></div><br class="" 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;"><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="">_______________________________________________</span><br 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;" 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="">swift-evolution mailing list</span><br 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;" class=""><a href="mailto:swift-evolution@swift.org" 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;" class="">swift-evolution@swift.org</a><br 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;" class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" 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;" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a></div></blockquote></div><br class=""></div></blockquote></body></html>