kotlin.text.Indent.kt Maven / Gradle / Ivy
@file:kotlin.jvm.JvmMultifileClass
@file:kotlin.jvm.JvmName("StringsKt")
package kotlin.text
/**
* Trims leading whitespace characters followed by [marginPrefix] from every line of a source string and removes
* first and last lines if they are blank (notice difference blank vs empty). Doesn't affect line if it doesn't contain
* [marginPrefix] except first and last blank lines
*
* Do not preserves original line endings
*
* [marginPrefix] should be non-blank string
*
* Example
* ```kotlin
* assertEquals("ABC\n123\n456", """ABC
* |123
* |456""".trimMargin())
* ```
*
* @param marginPrefix characters to be used as a margin delimiter. Default is `|` (pipe character)
* @return the trimmed String
* @see kotlin.isWhitespace
* @since M13
*/
public fun String.trimMargin(marginPrefix: String = "|"): String =
replaceIndentByMargin("", marginPrefix)
/**
* Detects indent by [marginPrefix] as it does [trimMargin] and replace it with [newIndent]
*/
public fun String.replaceIndentByMargin(newIndent: String = "", marginPrefix: String = "|"): String {
require(marginPrefix.isNotBlank()) { "marginPrefix should be non blank string but it is '$marginPrefix'" }
val lines = lines()
return lines.reindent(length + newIndent.length * lines.size, getIndentFunction(newIndent), { line ->
val firstNonWhitespaceIndex = line.indexOfFirst { !it.isWhitespace() }
when {
firstNonWhitespaceIndex == -1 -> null
line.startsWith(marginPrefix, firstNonWhitespaceIndex) -> line.substring(firstNonWhitespaceIndex + marginPrefix.length)
else -> null
}
})
}
/**
* Detects a common minimal indent of all the input lines, removes it from every line and also removes first and last
* lines if they are blank (notice difference blank vs empty).
* Note that blank lines do not affect detected indent level.
* Please keep in mind that if there are non-blank lines with no leading whitespace characters (no indent at all) then the
* common indent is 0 so this function may do nothing so it is recommended to keep first line empty (will be dropped).
*
* Do not preserves original line endings
*
* Example
* ```kotlin
* assertEquals("ABC\n123\n456", """
* ABC
* 123
* 456""".trimMargin())
* ```
*
* @return deindented String
* @see kotlin.isBlank
* @since M13
*/
public fun String.trimIndent(): String = replaceIndent("")
/**
* Detects a common minimal indent like it does [trimIndent] and replaces it with the specified [newIndent]
* @since M13
*/
public fun String.replaceIndent(newIndent: String = ""): String {
val lines = lines()
val minCommonIndent = lines
.filter { it.isNotBlank() }
.map { it.indentWidth() }
.min() ?: 0
return lines.reindent(length + newIndent.length * lines.size, getIndentFunction(newIndent), { line -> line.drop(minCommonIndent) })
}
/**
* Prepends [indent] to every line of the original string. Does not preserve original line endings
*/
public fun String.prependIndent(indent: String = " "): String =
lineSequence()
.map {
when {
it.isBlank() -> {
when {
it.length < indent.length -> indent
else -> it
}
}
else -> indent + it
}
}
.joinToString("\n")
private fun String.indentWidth(): Int = indexOfFirst { !it.isWhitespace() }.let { if (it == -1) length else it }
private fun getIndentFunction(indent: String) = when {
indent.isEmpty() -> { line: String -> line }
else -> { line: String -> indent.concat(line) }
}
private inline fun List.reindent(resultSizeEstimate: Int, indentAddFunction: (String) -> String, indentCutFunction: (String) -> String?): String {
val lastIndex = lastIndex
return mapIndexedNotNull { index, value ->
if ((index == 0 || index == lastIndex) && value.isBlank())
null
else
indentCutFunction(value)?.let { cutted -> indentAddFunction(cutted) } ?: value
}
.joinTo(StringBuilder(resultSizeEstimate), "\n")
.toString()
}