Kotlin add carriage return into multiline string

Question

In Kotlin, when I build a multiline string like this:

value expected = """
                |digraph Test {
                |${'\t'}Empty1;
                |${'\t'}Empty2;
                |}
                |""".trimMargin()

I see that the string lacks carriage return characters (ASCII code 13) when I output it via:

println("Expected bytes")
println(expected.toByteArray().contentToString())

Output:

Expected bytes
[100, 105, 103, 114, 97, 112, 104, 32, 84, 101, 115, 116, 32, 123, 10, 9, 69, 109, 112, 116, 121, 49, 59, 10, 9, 69, 109, 112, 116, 121, 50, 59, 10, 125, 10]

When some code I'm trying to unit test builds the same String via a PrintWriter it delineates lines via the lineSeparator property:

/* 
 * Line separator string.  This is the value of the line.separator
 * property at the moment that the stream was created.
 */

So I end up with a string which looks the same in output, but is composed of different bytes and thus is not equal:

Actual bytes
[100, 105, 103, 114, 97, 112, 104, 32, 84, 101, 115, 116, 32, 123, 13, 10, 9, 69, 109, 112, 116, 121, 49, 59, 13, 10, 9, 69, 109, 112, 116, 121, 50, 59, 13, 10, 125, 13, 10]

Is there a better way to address this during string declaration than splitting my multiline string into concatenated stringlets which can each be suffixed with char(13)?

Alternately, I'd like to do something like:

value expected = """
                |digraph Test {
                |${'\t'}Empty1;
                |${'\t'}Empty2;
                |}
                |""".trimMargin().useLineSeparator(System.getProperty("line.separator"))

or .replaceAll() or such.

Does any standard method exist, or should I add my own extension function to String?

It may be better to read https://en.wikipedia.org/wiki/Newline Especially the first table part. — Naetmul, Feb 22 '18 at 17:54

score 40 · Answer 1 · answered Nov 17 '19 at 02:46

40

This did the trick.

    System.lineSeparator()

answered Nov 17 '19 at 02:46

Ahamed Mujeeb

615
1
8
13

score 20 · Accepted Answer · answered Feb 23 '18 at 09:58

Kotlin multiline strings are always compiled into string literals which use \n as the line separator. If you need to have the platform-dependent line separator, you can do replace("\n", System.getProperty("line.separator")).

As of Kotlin 1.2, there is no standard library method for this, so you should define your own extension function if you're using this frequently.

Kotlin add carriage return into multiline string

2 Answers2