[swift-evolution] [Review] SE-0168: Multi-Line String Literals

[Muse M]

This would be prefer to follow Scala multiline string which look

1) //Default
var code = """header
paragraph1"""

*Output:*
>header
>paragraph1

2)
var code = """
...header...
...paragraph1...
""".replace("...")

*Output:*
>header
>paragraph1

3)
var code = """
         |..header...
         |..paragraph1...
""".stripLeadingSpace()

*Output:*
>header...
>paragraph1...

4)
var code = """

import Foundation
print("Hello World!")

""".code()

*Output:*
>
>import Foundation
>print("Hello World!")
>

5)
//To remove all new lines
var code = """
import Foundation

import Cocoa

....print("Hello World!")
""".compactLine()

*Output:*
>import Foundation
>import Cocoa
>....print("Hello World!")



On Multiline String collection

6) If we are importing many sources from 3rd parties API, we won't know if
their code is properly indent, some use tab and some use 2 or 4-space. This
would look better on Swift Playground app.

var *stories* = {
"""
Chapter1
第1章

Introduction to A
""",
"""
Chapter2
第2章

Introduction to B
""",
"""
//Code Example
    import Foundation
"""
}

We can loop or apply to certain collection
stories(3).code()



On Saturday, April 15, 2017, Ricardo Parada via swift-evolution <
swift-evolution at swift.org> wrote:

> I agree that it is not obvious.
>
> At one point I argued that the trailing newline on the last line should be
> stripped. But for this reason and others I am now in the camp that thinks
> we should leave the trailing newline alone.
>
> If we don't want to include the trailing newline we can always do this:
>
> let str = """
>    Line 1
>    Line 2\
>    """
>
> This is were it's difficult to get consensus.
>
> Regards,
> Ricardo
>
>
> On Apr 14, 2017, at 5:54 PM, BJ Homer via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> I’m not saying that the + operator should automatically add a newline. I’m
> saying that both strings should contain a trailing newline, such that the
> visible result is the same.
>
> By contrast, this would feel really strange:
>
> let a = """
> This is line one
> This is line two
>
>
> """
>
>
> let b = """
> This is line three
> This is line four
>
> """
>
>
> (a + b) == """
> This is line one
> This is line two
> This is line three
> This is line four
> """
>
>
> On initial intuition, it seems strange that ‘a’ has a blatantly visible
> blank line at the end which seemingly “disappears” when the strings are
> concatenated. If I think about it for a bit, I can understand why that
> would be the case, but I think it’s non-obvious.
>
> -BJ
>
> On Apr 14, 2017, at 3:49 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
>
> I disagree. I expect the last result to be from `a + "\n" + b`, for the
> reasons I outlined earlier.
>
> The concatenation operator + does not introduce implied separators when
> joining strings. There is no reason to think that it should for multi-line
> strings specifically.
> On Fri, Apr 14, 2017 at 16:35 BJ Homer via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>>
>> Consider these two examples:
>>
>> let string_1 = """foo"""
>>
>>
>> let string_2 = """
>>     foo
>>     """
>>
>> What’s the intuitive result you’d expect without taking all the long talk
>> from the list into account?
>>
>> Personally, I’d say string_1 == string_2 is true.
>>
>>
>> I think it’s reasonable to expect them to be different, actually. I might
>> call these “single-line” and “multi-line” mode strings. The single-line
>> mode is primarily useful for being able to include unescaped double-quotes
>> in the string. If you’re in multi-line mode, though, it’s reasonable to be
>> thinking about things in terms of “lines”, and having a trailing newline
>> there seems reasonable. For example, I think it’s reasonable to expect this:
>>
>> let a = """
>> This is line one
>> This is line two"
>> """
>>
>> let b = """
>> This is line three
>> This is line four
>> """
>>
>> (a + b) == """
>> This is line one
>> This is line two
>> This is line three
>> This is line four
>> """
>>
>>
>> That seems like a reasonable model to work with multi-line strings.
>>
>> -BJ
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution at swift.org
>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>
>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
>
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