How to bind data in heredoc of scala?

Question

val name = "mike"
val str = """Hi, {name}!"""
println(str)

I want it output the str as Hi, mike!, but failed. How to do this?

Similar question http://stackoverflow.com/questions/2183503/substitute-values-in-a-string-with-placeholders-in-scala — pascal, Jul 26 '10 at 17:29

score 5 · Accepted Answer · answered Jul 26 '10 at 17:35

5

Scala does not support string interpolation. There is a compiler plugin that implements it at http://github.com/jrudolph/scala-enhanced-strings.

Without the plugin you can use concatenation or format strings:

val str = name formatted "Hi, %s!"

or of course

val str = "Hi, %s!".format(name)

answered Jul 26 '10 at 17:35

Moritz

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@Moritz, thank you for your answer. I don't understand why scala not support it heredoc, since they support it in xml – Freewind Jul 26 '10 at 17:47
@Freewind in XML literals the curly braces are actually just a fancy syntax for inserting an instance of scala.xml.Text with the string value of the block into the XML nodes. XML is a bit special here but Strings are just Strings to the compiler. – Moritz Jul 26 '10 at 18:05
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@Freewind Also see this discussion on why Scala doesn't support string interpolation: http://goo.gl/cJ5u – missingfaktor Jul 26 '10 at 19:15
You can also make `format` more Pythonic with an implicit: http://www.bubblefoundry.com/blog/2010/06/fun-with-scala-implicits/ – pr1001 Jul 26 '10 at 21:34
@Rahuλ G, I can't open the http://goo.gl/cJ5u, but I want to see it much. Can you open it ? – Freewind Jul 27 '10 at 04:51
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@Freewind, Yes, I am able to open it. You can try this direct link if the shortened URL isn't working: http://scala-programming-language.1934581.n4.nabble.com/Why-Martin-hates-string-interpolation-Was-Re-Formatting-Questions-Summary-td2008748.html – missingfaktor Jul 27 '10 at 12:31
@Rahuλ G, it's very interesting. Is really because of keyboard? – Freewind Jul 27 '10 at 13:29
@Freewind, As he himself clarified in the discussion, Odersky uses a US keyboard. So this Swiss keyboard theory is obviously wrong. :) – missingfaktor Jul 27 '10 at 13:33
@Rahuλ, yes :) So, the true reason is a secret – Freewind Jul 27 '10 at 13:48
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This is outdated! String interpolation exists in scala, refer to @javabda's answer: http://stackoverflow.com/a/23875645/5214346 – Jean Bob May 19 '17 at 09:56

score 5 · Answer 2 · answered Jul 26 '10 at 21:56

5

A total hackish solution would be to use Scala's XML interpolation:

val name = "Mike"
val str = <a>Hi, {name}!</a> text

The text method returns string contents of an XML construct, so our tags are stripped.

answered Jul 26 '10 at 21:56

pr1001

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+1 This is basically a "canonical" hack. Maybe being so accepted (and useful) this is not really a "hack" anymore?? – WestCoastProjects May 26 '14 at 18:20

score 4 · Answer 3 · answered May 26 '14 at 18:07

4

As of scala >= 2.10 string interpolations are supported:

val str = "Foo Bar"
str: String = Foo Bar

scala> s"Interpolating: $str"
res0: String = Interpolating: Foo Bar

answered May 26 '14 at 18:07

WestCoastProjects

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How to bind data in heredoc of scala?

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