[swift-evolution] multi-line string literals.

[Tony Allevato]

I just checked with -O and without and was surprised to find that `let x =
"abc" + "def" + "ghi"` wasn't collapsed into a single string literal
"abcdefghi" in the generated assembly code. Maybe it's more difficult than
it is in some other languages because of operator overloads and different
kinds of text literals (strings, extended grapheme clusters, Unicode
scalars)?

Regardless of the reasons, a separate syntax isn't the right way to achieve
this optimization—the compiler should just do it automatically. Like
Ricardo, "multi-line string literals" should be reserved for string
literals that include the newline characters that are used to break them up
in source. The idea of supporting something like the Python example above
just provides two ways to do the same thing, which I don't think we really
need.


On Mon, Apr 3, 2017 at 8:18 AM Ricardo Parada via swift-evolution <
swift-evolution at swift.org> wrote:

>
> I would think that the concatenation would get resolved at runtime, unless
> the compiler gets smart about it.  But either way I do not see it as a
> problem.  The reason is that I don't remember ever worrying about the
> performance of concatenating a few lines of text.  :-)
>
> Thanks
>
>
> On Apr 3, 2017, at 11:13 AM, Adrian Zubarev <
> adrian.zubarev at devandartist.com> wrote:
>
> To me a literal a single entity which is solved at compile time. The
> concatenation is however resolved at runtime if I’m not mistaken here (it
> might be optimized at compile time but I still would expect a function
> executed a couple of times at runtime).
>
> Please correct me if I’m wrong here.
>
>
>
> --
> Adrian Zubarev
> Sent with Airmail
>
> Am 3. April 2017 um 17:10:36, Ricardo Parada (rparada at mac.com) schrieb:
>
> How is that better than this?
>
> template = "This is the first line.\n" +
>             "This is the second line.\n" +
>             "This is the third line."
>
>
> On Apr 3, 2017, at 10:42 AM, Ricardo Parada via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> It look prettier without the \n
>
> It's not laziness.
>
> I want my code to look pretty.
>
>
> On Apr 3, 2017, at 10:40 AM, Adrian Zubarev <
> adrian.zubarev at devandartist.com> wrote:
>
> What I was trying to say is that by automatically adding a new line
> character does not provide any benefit except of being lazy to type \n.
>
> // In your model this would be equivalent
> let s1 = "\n\n\n"
> let s2 = """
>     " // However in my model this is an empty string and should be banned
>     "
>     """ // That's also an empty string, but it that case it indicates the end of the multi lined string
>
> I dislike the tradeoff of precision for laziness.
>
>
>
> --
> Adrian Zubarev
> Sent with Airmail
>
> Am 3. April 2017 um 16:29:44, Ricardo Parada (rparada at mac.com) schrieb:
>
> By the way, the multi-line string should allow \n\n, or as many as you may
> want to throw in there.  I don't see a problem with that.
>
>
>
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