Short for String.format in Scala

Question

Is there a short syntax for string interpolation in Scala? Something like:

"my name is %s" < "jhonny"

Instead of

"my name is %s" format "jhonny"

New vocab word for you: string interpolation (I learned that one recently myself).. — Mike Christensen, Oct 10 '11 at 18:20
Yea I found this too: http://stackoverflow.com/questions/2481459/why-is-there-no-string-interpolation-in-scala — Mike Christensen, Oct 10 '11 at 18:23
Not sure if I should delete the question or mark it as duplicate. Some(like me) might be looking for String.format instead of formal terms :) — Johnny Everson, Oct 10 '11 at 18:28
You never know, Scala might yet get String interpolation: https://github.com/scala/scala/commit/6975fc7fe11a4f0e6abdbd88580085cb404c34e8 — retronym, Oct 10 '11 at 18:53
So now scala is commercial hand they have to listen to customers. Very nice! — Ido Tamir, Oct 11 '11 at 07:05

score 9 · Accepted Answer · answered Oct 10 '11 at 18:31

No, but you can add it yourself:

scala> implicit def betterString(s:String) = new { def %(as:Any*)=s.format(as:_*) }
betterString: (s: String)java.lang.Object{def %(as: Any*): String}

scala> "%s" % "hello"
res3: String = hello

Note that you can't use <, because that would conflict with a different implicit conversion already defined in Predef.

score 4 · Answer 2 · answered Oct 11 '11 at 07:09

In case you are wondering what syntax may be in the works

$ ./scala -nobootcp -Xexperimental
Welcome to Scala version 2.10.0.r25815-b20111011020241 

scala> val s = "jhonny"
s: String = jhonny

scala> "my name is \{ s }"
res0: String = my name is jhonny

Playing some more:

scala> "those things \{ "ne\{ "ts".reverse }" }"
res9: String = those things nest

scala> println("Hello \{ readLine("Who am I speaking to?") }")
Who am I speaking to?[typed Bozo here]Hello Bozo

score 3 · Answer 3 · answered Oct 10 '11 at 18:34

3

I seem to remember Martin Odersky having been quoted with stating that string concatenation in the style presented in "Programming in Scala" is a useful approximation to interpolation. The idea is that without spaces you are only using a few extra characters per substitution. For example:

val x     = "Mork"
val y     = "Ork"

val intro = "my name is"+x+", I come from "+y

The format method provides a lot more power however. Daniel Sobral has blogged on a regex based technique too.

answered Oct 10 '11 at 18:34

Don Mackenzie

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The problem with concatenation is that sometimes you lose the 'view' for the whole string. e.g. "%s://%s" format (protocol, host) looks cleaner to me. – Johnny Everson Oct 10 '11 at 18:42

Short for String.format in Scala

3 Answers3