hellovass / kotlin-trim-indent

This is a Kotlin compiler plugin for a compile-time indent trim of raw String.

Trim Indent

This is a Kotlin compiler plugin for a compile-time indent trim of raw String. It is pretty useful for String templates with multiline String variables.

Examples

We have two Strings as below:

val s = """
    hello
    world
    !!!
""".trimIndent()

val s2 = """
    $s
    hello2
    world2
    !!!
""".trimIndent()

After compilation, we will get:

val s = "\n    hello\n    world\n    !!!\n".trimIndent()
val s2 = "\n    " + s + "\n    hello2\n    world2    !!!\n".trimIndent()

No spaces are dropped in the compile-time.

In the runtime, the trimIndent function is called. For s, the common indent will be removed as expected:

hello
world
!!!

But for s2, things are going to be weird.

    hello
world
!!!
    hello2
    world2
    !!!

This is because the computation of common indent size is based on the runtime String value which also contains the new lines of s.

With this plugin installed, the runtime value of String template variables are ignored, and only the white spaces of the String literal will be removed so that s2 will be like:

hello
world
!!!
hello2
world2
!!!

With version 1.7.10.3, you can also do this magic:

val s1 = """
    if(a > 1) {
        return true
    }
""".trimIndent()
val s2 = """
    def test(a) {
        $s1
    }
""".trimIndent()

val s3 = """
    class Test {
        $s2
    }
""".trimIndent()

The result value of s3 will be:

class Test {
    def test(a) {
        if(a > 1) {
            return true
        }
    }
}

It is really useful when you use Kotlin String template as a template to render some other Strings.

Try it

plugins {
    ...
    id("com.bennyhuo.kotlin.trimindent") version "1.8.0"
}

For snapshot:

buildscript {
    repositories {
        ...
        maven("https://oss.sonatype.org/content/repositories/snapshots/")
    }
}

plugins {
    ...
    id("com.bennyhuo.kotlin.trimindent") version "1.8.1-SNAPSHOT"
}

Change Log

1.8.0

• Upgrade Kotlin to 1.8.0.

1.7.10.3

• Fix: A newline was mistakenly inserted after an interpolated variable.
• Feat: Reindent the whole value of the interpolated variable.

1.7.10.2

Compatible with Java 8.

1.7.10.1

Compatible with Kotlin 1.7.10.

1.6.10.1

Compatible with Kotlin 1.6.10.