<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=""><br class=""><div><blockquote type="cite" class=""><div class="">On May 20, 2016, at 8:01 PM, Erica Sadun 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=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On May 20, 2016, at 11:53 AM, Matthew Johnson <<a href="mailto:matthew@anandabits.com" class="">matthew@anandabits.com</a>> wrote:</div><div class=""><div style="font-family: Palatino-Roman; font-size: 14px; 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=""><div class="">I am less certain about allowing simple boolean expressions that are not introduced by the `where` keyword (excepting the first one which is introduced with the `guard` keyword). I think this is a separate question that should receive independent consideration. I think a reasonable argument can be made both ways. </div></div></div></blockquote><br class=""></div><div class="">That's kind of the heart of the matter.</div><div class=""><br class=""></div><div class="">There's an assumption that guard statements are:</div><div class=""><br class=""></div><div class=""><font face="Menlo" class="">`guard` (conjoined boolean tests) | (conjoined boolean tests,)? (pattern | binding (where boolean)?, )+ else {...}</font></div><div class=""><br class=""></div><div class="">Right? (Except I couldn't figure out how to grammar out the final comma,) I'm suggesting:</div><div class=""><br class=""></div><div class=""><font face="Menlo" class="">`guard` ((boolean | (pattern | binding (where boolean)?)),)+ else {...}</font></div><div class=""><br class=""></div><div class="">instead. (And ditto about final comma) This promotes boolean statements to the same standing, so they're not limited to the start of the guard statement or syntactically tied to a pattern/binding where there may be no semantic basis.</div><div class=""><br class=""></div><div class="">-- E</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div></div></div></blockquote><div><br class=""></div><div><section class="section" style="padding: 0px; margin: 30px 0px 0px; font-family: Helvetica, Arial, sans-serif; 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 A GUARD STATEMENT</p><div class="syntax-defs-group" style="border: 0px; margin: 0px 0px 12px; outline: 0px; padding: 0px; vertical-align: baseline;"><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/swift/grammar/guard-statement" 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);" class=""></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;">guard-statement </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;">guard</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/condition-clause" data-renderer-version="2" data-id="//apple_ref/swift/grammar/condition-clause" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">condition-clause</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;">else</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/Declarations.html#//apple_ref/swift/grammar/code-block" data-renderer-version="2" data-id="//apple_ref/swift/grammar/code-block" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">code-block</a></span></div></div></div></section></div><div><div class="syntax-defs-group" style="border: 0px; font-size: 14px; margin: 0px 0px 12px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Helvetica, Arial, sans-serif;"><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/swift/grammar/condition-clause" 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);" class=""></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;">condition-clause </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/Expressions.html#//apple_ref/swift/grammar/expression" data-renderer-version="2" data-id="//apple_ref/swift/grammar/expression" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">expression</a></span></div><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_501" 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);" class=""></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;">condition-clause </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/Expressions.html#//apple_ref/swift/grammar/expression" data-renderer-version="2" data-id="//apple_ref/swift/grammar/expression" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">expression</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/condition-list" data-renderer-version="2" data-id="//apple_ref/swift/grammar/condition-list" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">condition-list</a></span></div><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_502" 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);" class=""></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;">condition-clause </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/condition-list" data-renderer-version="2" data-id="//apple_ref/swift/grammar/condition-list" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">condition-list</a></span></div><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/doc/uid/TP40014097-CH33-NoLink_503" 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);" class=""></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;">condition-clause </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/availability-condition" data-renderer-version="2" data-id="//apple_ref/swift/grammar/availability-condition" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">availability-condition</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/Expressions.html#//apple_ref/swift/grammar/expression" data-renderer-version="2" data-id="//apple_ref/swift/grammar/expression" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">expression</a></span></div></div><div class="syntax-defs-group" style="border: 0px; font-size: 14px; margin: 0px 0px 12px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Helvetica, Arial, sans-serif;"><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/swift/grammar/condition-list" 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);" class=""></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;">condition-list </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/condition" data-renderer-version="2" data-id="//apple_ref/swift/grammar/condition" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">condition</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/condition" data-renderer-version="2" data-id="//apple_ref/swift/grammar/condition" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">condition</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/condition-list" data-renderer-version="2" data-id="//apple_ref/swift/grammar/condition-list" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">condition-list</a></span></span></div><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/swift/grammar/condition" 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);" class=""></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;">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><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-condition" data-renderer-version="2" data-id="//apple_ref/swift/grammar/availability-condition" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">availability-condition</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/case-condition" data-renderer-version="2" data-id="//apple_ref/swift/grammar/case-condition" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">case-condition</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/optional-binding-condition" data-renderer-version="2" data-id="//apple_ref/swift/grammar/optional-binding-condition" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">optional-binding-condition</a></span></span></div><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><a name="//apple_ref/swift/grammar/case-condition" 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);" class=""></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;">case-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;">case</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/Patterns.html#//apple_ref/swift/grammar/pattern" data-renderer-version="2" data-id="//apple_ref/swift/grammar/pattern" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">pattern</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/Declarations.html#//apple_ref/swift/grammar/initializer" data-renderer-version="2" data-id="//apple_ref/swift/grammar/initializer" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">initializer</a></span><span class="optional" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><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/where-clause" data-renderer-version="2" data-id="//apple_ref/swift/grammar/where-clause" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 136, 204); text-decoration: none;" class="">where-clause</a></span><sub class="subscript" style="border: 0px; font-size: 0.8em; margin: 0px 0px 0px -2px; outline: 0px; padding: 0px 4px 0px 0px; color: rgb(128, 128, 128); font-style: italic;">opt</sub></span></div></div><div class="syntax-defs-group" style="border: 0px; font-size: 14px; margin: 0px 0px 12px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Helvetica, Arial, sans-serif;"><div style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""></div></div></div><div><br class=""></div><div>it is all shared at the moment. </div><div><br class=""></div><div><div style="margin: 0px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">/// stmt-guard:</span></div><div style="margin: 0px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">/// 'guard' condition 'else' stmt-brace</span></div><div style="margin: 0px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">///</span></div><div style="margin: 0px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">ParserResult</span><span style="font-variant-ligatures: no-common-ligatures" class=""><</span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">Stmt</span><span style="font-variant-ligatures: no-common-ligatures" class="">> </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">Parser</span><span style="font-variant-ligatures: no-common-ligatures" class="">::parseStmtGuard() {</span></div><div style="margin: 0px; line-height: normal; font-family: Menlo; color: rgb(49, 89, 93);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">SourceLoc</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> GuardLoc = </span><span style="font-variant-ligatures: no-common-ligatures" class="">consumeToken</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">tok</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">::</span><span style="font-variant-ligatures: no-common-ligatures" class="">kw_guard</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">);</span></div><p style="margin: 0px; line-height: normal; font-family: Menlo; min-height: 14px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><br class="webkit-block-placeholder"></p><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">...</span></div></div><div><br class=""></div><div><br class=""></div><div>I guess it means that stepping out of what it currently does is straightforward to isolate from side effects, but likely a significant piece of work if it is not make a superset (meaning that bits and parts or the way the current grammar is structured can be reused in the manner they are today) of what it is today.</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=""><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><br class=""></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=""></body></html>