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.send { color:#77bb77; }
.server { color:#7799bb; }
.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>The multi-line string literal as it’s accepted right now only allows pretty code generation with smaller lines. The literal itself is not reserved for JSON, XML and similar syntaxes only, which automatically implies the existence of conventions with longer lines. For whatever reasons a developer might have, it’s essential to allow manual line wrapping without injecting a new line into the resulting string. Not everyone uses the same editor width nor the same editor with exact the same settings. You simply cannot and really should not rely on any editor or linter for that matter, nor do I vision it as a strong argument against having the ability to escape the new line injection. I don’t think we should ever expect the average Swift developer sitting in-front of an ultra wide monitor.</p>
<p>Consider this example:</p>
<pre><code class="swift">// Currently it would look like this:
let myLongString = "Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.\n\nNam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.\n\nDuis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis."
// With the accepted version of the proposal it becomes a little bit better, but still to long,
// because we can only replace `\n` characters with lines and that's it.
let myLongString = """
Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis.
"""
// This is how it should ideally look like and be editor/IDE/linter independent.
// The string produces the same result as above and does not rely on any
// soft-wrapping functionality and is written within some smaller line width.
// The trailing precision is a really good tradeoff at this point.
let myLongString = """
Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit \
lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure \
dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore \
eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui \
blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming \
id quod mazim placerat facer possim assum. Lorem ipsum dolor sit amet, consectetuer \
adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna \
aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation \
ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie \
consequat, vel illum dolore eu feugiat nulla facilisis.
"""
</code></pre>
<hr>
<p>The string concatenation uses optimization magic behind the scenes which is not obvious for everyone. I personally think that every operation involved in concatenation or any operation in-general adds a performance overhead and theoretically needs more time to resolve the expression at runtime, which is the natural way of thinking without any knowledge about the optimization the compiler is able to do for you. A string literal is able to solve that issue during compile time is simply the perfect place for that.</p>
<hr>
<p>Some words about the trailing precision. Joe said that we could use <code>\("")</code> as workaround, but if I recall correctly literals are banned from the interpolation itself, which will result in us doing something like this:</p>
<pre><code class="swift">let end = ""
let myString = """
<space><space>foo<space><space>\(end)
"""
</code></pre>
<p>This is a very dirty and tedious solution for that problem.</p>
<p>As accepted right now, no one should ever expect the result string to include any whitespace characters at the end of each line unless there is a visible annotation provided for precision. Providing a warning for trailing whitespace characters would be ideal solution right now and the trailing backslash becomes additive but not impossible to add later.</p>
<hr>
<p>A few people already argued that the core team decided not to include a new line at the end of each multi-line string, where you yourself said that the absence of a trailing backslash will produce a string which always ends with a new line. That behavior would be really strange and painful to prevent if there is no backslash for escaping it.</p>
<p>The trailing backslash does not add any complexity but instead it adds more flexibility to the literal model, which results in better readability if the precision is desired for code formatting!</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <br> <div id="bloop_sign_1492706130704740096" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div> <br><p class="airmail_on">Am 20. April 2017 um 07:30:29, Xiaodi Wu (<a href="mailto:xiaodi.wu@gmail.com">xiaodi.wu@gmail.com</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>
<title></title>
You can use a plain text editor and no linter, or a plain text
editor and a linter, or an IDE and no linter, etc., and in any of
these scenarios you can already choose whether or not you want
trailing newlines stripped. Why should the compiler try to enforce
any rules here?<br>
<br>
<div>Since Unicode is supported, it is never possible to look at a
string literal and be 100% sure of what glyphs are involved. We
should be clear that such a criterion cannot and should not be a
design goal. If it supports Unicode and is really literal, then
confusables and invisibles will make it impossible to be sure of
what you see; you would have to either stop supporting Unicode or
stop being literal.<br>
<br>
I'm not sure this "coding style" you describe can properly be
thought of as a multiline string literal. It sounds like what you
want isn't multiline (in fact, you want a new way to write a very
long single-line string) and it isn't literal (you want to use
newlines in your code that do not represent a literal newline). If
there is something extremely critical about a particular string,
where you simply must start half of it on a separate line to help
the readers of your code understand what you are doing, you can
already do this by writing "foo" + [newline] "bar". Or you could
just let your editor soft-wrap your long string. Making your
single-line string wrap the same way in every IDE just doesn't seem
like it's related to or worth complicating the syntax for multiline
string literals. I would be strongly opposed to such a
feature.</div>
<div><br>
<br>
<div class="gmail_quote">
<div>On Wed, Apr 19, 2017 at 23:42 Adrian Zubarev via
swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>>
wrote:<br></div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">
<div class="m_-6208984668242159980m_3629141258267239431bloop_markdown">
<p>True, but this is not about IDEs or editors. The feature itself
doesn’t know what an editor is and what it capable of, nor should
be ever rely on that. Not everyone uses the same settings and you
cannot be 100% sure to expect the same string from looking at it,
which was written in a different editor if we don’t warn about
trailing whitespaces now.</p>
<p>The trailing whitespaces might not do any harm for the currently
accepted version, but we’ll have to warn about them if we decide to
add the trailing backspace. As currently accepted we still have a
hole to fill for coding styles, we do not support multi-lined
string literals for code formatting only, nor do we have trailing
precision for the same matter. (That’s what the backslash was meant
for.) That said, I cannot break up a really long hardcoded string,
which in my IDE is softly wrapped, into a multi-line string literal
so that it looks in every editor the same and still expect the same
result and be precise about the trailing whitespace characters.</p>
</div>
<div class="m_-6208984668242159980m_3629141258267239431bloop_original_html">
</div>
</div>
<div style="word-wrap:break-word">
<div class="m_-6208984668242159980m_3629141258267239431bloop_original_html">
<div id="m_-6208984668242159980m_3629141258267239431bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<br></div>
<br>
<div id="m_-6208984668242159980m_3629141258267239431bloop_sign_1492662767413933056" class="m_-6208984668242159980m_3629141258267239431bloop_sign">
<div style="font-family:helvetica,arial;font-size:13px">
-- <br>
Adrian Zubarev<br>
Sent with Airmail</div>
</div>
<br></div>
</div>
<div style="word-wrap:break-word">
<div class="m_-6208984668242159980m_3629141258267239431bloop_original_html">
<p class="m_-6208984668242159980m_3629141258267239431airmail_on">Am
20. April 2017 um 00:27:48, Brent Royal-Gordon via swift-evolution
(<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>) schrieb:</p>
</div>
</div>
<div style="word-wrap:break-word">
<div class="m_-6208984668242159980m_3629141258267239431bloop_original_html">
<blockquote type="cite" class="m_-6208984668242159980m_3629141258267239431clean_bq">
<div style="word-wrap:break-word">
<div>
<div>
<blockquote type="cite">
<div><span>On Apr 19, 2017, at 3:18 PM, Xiaodi Wu via
swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>>
wrote:</span></div>
<span><br class="m_-6208984668242159980m_3629141258267239431Apple-interchange-newline">
</span>
<div>
<blockquote class="gmail_quote" style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
<div style="word-wrap:break-word">
<div>
<div><span>Other common tools like Git already flag trailing
whitespace by default, so even if Swift doesn't warn about it, you
might still need to satisfy other tools in your
pipeline.</span></div>
</div>
</div>
</blockquote>
<div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
<span><br></span></div>
<div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
<span>Isn't that an equally good argument for Swift *not* warning
you about it? If it's harmful, you'll have other tools in the
pipeline to flag it for you.</span></div>
</div>
</blockquote>
</div>
<div><span><br></span></div>
<div><span>Cosigned. We already have an Xcode setting to strip
trailing whitespace, a Git setting to flag it, and linter settings
to remove it. (For instance, SwiftFormat has a --trimwhitespace
flag.) Not every tool needs to handle every case of questionable
style.</span></div>
<span><br></span>
<div>
<div>
<div style="font-size:12px"><span><span class="m_-6208984668242159980m_3629141258267239431Apple-style-span" style="border-collapse:separate;color:rgb(0,0,0);font-family:Helvetica;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
-- </span></span></div>
<div style="font-size:12px"><span class="m_-6208984668242159980m_3629141258267239431Apple-style-span" style="border-collapse:separate;color:rgb(0,0,0);font-family:Helvetica;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
Brent Royal-Gordon</span></div>
<div style="font-size:12px"><span class="m_-6208984668242159980m_3629141258267239431Apple-style-span" style="border-collapse:separate;color:rgb(0,0,0);font-family:Helvetica;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
Architechies</span></div>
</div>
</div>
<br></div>
</div>
</blockquote>
</div>
</div>
<div style="word-wrap:break-word">
<div class="m_-6208984668242159980m_3629141258267239431bloop_original_html">
<blockquote type="cite" class="m_-6208984668242159980m_3629141258267239431clean_bq">
<div style="word-wrap:break-word">
<div><span>_______________________________________________<br>
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</blockquote>
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</div>
_______________________________________________<br>
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</blockquote>
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