[swift-evolution] multi-line string literals.

Adrian Zubarev adrian.zubarev at devandartist.com
Mon Apr 3 02:01:15 CDT 2017

Hello Swift community,

on Github there is a PR for this proposal, but I couldn’t find any up to date thread, so I’m going to start by replying to the last message I found, without the last content.

I really like where this proposal is going, and my personal preference are *continuation quotes*. However the proposed solution is still not perfect enough for me, because it still lacks of precise control about the trailing space characters in each line of a multi-line string.

Proposed version looks like this:

let xml = "<?xml version=\"1.0\"?>
    "    <book id=\"bk101\" empty=\"\">
    "        <author>\(author)</author>
    "        <title>XML Developer's Guide</title>
    "        <genre>Computer</genre>
    "        <price>44.95</price>
    "        <publish_date>2000-10-01</publish_date>
    "        <description>An in-depth look at creating applications with XML.</description>
    "    </book>
I would like to pitch an enhancement to fix the last tiny part by adding the escaping character ‘' to the end of each line from 1 to (n - 1) of the n-lined string. This is similar to what Javascript allows us to do, except that we also have precise control about the leading space character through ’"’.

The proposed version will become this:

let xml = "<?xml version=\"1.0\"?>\  
    "<catalog>\ // If you need you can comment here
    "    <book id=\"bk101\" empty=\"\">\
    "        <author>\(author)</author>\
    "        <title>XML Developer's Guide</title>\
    "        <genre>Computer</genre>\
    "        <price>44.95</price>\
    "        <publish_date>2000-10-01</publish_date>\
    "        <description>An in-depth look at creating applications with XML.</description>\
    "    </book>\
Here is another example:

let multilineString: String = "123__456__\ // indicates there is another part of the string on the next line
                              "__789_____\ // aways starts with `"` and ends with either `\` or `"`
                              "_____0_" // precise control about pre- and post-space-characters

let otherString = "\(someInstance)\ /* only comments are allowed in between */ "text \(someOtherInstance) text"
This is simply continuation quotes combined with backslash concatenation.

Adrian Zubarev
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