From 4c58f4ec2013afa43b7771fbccfca135d0c44d01 Mon Sep 17 00:00:00 2001
From: Ilya Gorbunov <ilya.a.gorbunov@yandex.ru>
Date: Thu, 19 Mar 2015 15:38:24 +0300
Subject: [PATCH] Add removeRange method. Breaking change in
 replaceRange(IntRange, String) method: the end index of the range now is
 included in the part being replaced.

---
 libraries/stdlib/src/kotlin/text/Strings.kt | 35 ++++++++++++++++-----
 libraries/stdlib/test/text/StringTest.kt    | 20 +++++++++++-
 2 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/libraries/stdlib/src/kotlin/text/Strings.kt b/libraries/stdlib/src/kotlin/text/Strings.kt
index cce8ec7a123..cb28cb4fa12 100644
--- a/libraries/stdlib/src/kotlin/text/Strings.kt
+++ b/libraries/stdlib/src/kotlin/text/Strings.kt
@@ -308,17 +308,38 @@ public fun String.replaceRange(firstIndex: Int, lastIndex: Int, replacement: Str
 
 /**
  * Replace the part of string at the given [range] with the [replacement] string.
+ *
+ * The end index of the [range] is included in the part to be replaced.
  */
-public fun String.replaceRange(range: IntRange, replacement: String): String {
-    if (range.end < range.start)
-        throw IndexOutOfBoundsException("Last index (${range.start}) is less than first index (${range.end})")
-    val sb = StringBuilder()
-    sb.append(this, 0, range.start)
-    sb.append(replacement)
-    sb.append(this, range.end, length)
+public fun String.replaceRange(range: IntRange, replacement: String): String = replaceRange(range.start, range.end + 1, replacement)
+
+/**
+ * Removes the part of a string at a given range.
+ * @param firstIndex the index of the first character to be removed.
+ * @param lastIndex the index of the first character after the removed part to keep in the string.
+*
+*  [lastIndex] is not included in the removed part.
+ */
+public fun String.removeRange(firstIndex: Int, lastIndex: Int): String {
+    if (lastIndex < firstIndex)
+        throw IndexOutOfBoundsException("Last index ($lastIndex) is less than first index ($firstIndex)")
+
+    if (lastIndex == firstIndex)
+        return this
+
+    val sb = StringBuilder(length() - (lastIndex - firstIndex))
+    sb.append(this, 0, firstIndex)
+    sb.append(this, lastIndex, length())
     return sb.toString()
 }
 
+/**
+ * Removes the part of a string at the given [range].
+ *
+ * The end index of the [range] is included in the removed part.
+ */
+public fun String.removeRange(range: IntRange): String = removeRange(range.start, range.end + 1)
+
 /**
  * Replace part of string before the first occurrence of given delimiter with the [replacement] string.
  * If the string does not contain the delimiter, returns [missingDelimiterValue] which defaults to the original string.
diff --git a/libraries/stdlib/test/text/StringTest.kt b/libraries/stdlib/test/text/StringTest.kt
index 9f520fbd8f6..2b6025b7af0 100644
--- a/libraries/stdlib/test/text/StringTest.kt
+++ b/libraries/stdlib/test/text/StringTest.kt
@@ -72,13 +72,31 @@ class StringTest {
     test fun replaceRange() {
         val s = "sample text"
         assertEquals("sa??e text", s.replaceRange(2, 5, "??"))
-        assertEquals("sa??e text", s.replaceRange(2..5, "??"))
+        assertEquals("sa?? text", s.replaceRange(2..5, "??"))
         fails {
             s.replaceRange(5..2, "??")
         }
         fails {
             s.replaceRange(5, 2, "??")
         }
+
+        // symmetry with indices
+        assertEquals("??", s.replaceRange(s.indices, "??"))
+    }
+
+    test fun removeRange() {
+        val s = "sample text"
+        assertEquals("sae text", s.removeRange(2, 5))
+        assertEquals("sa text", s.removeRange(2..5))
+
+        assertEquals(s, s.removeRange(2,2))
+
+        // symmetry with indices
+        assertEquals("", s.removeRange(s.indices))
+
+        // symmetry with replaceRange
+        assertEquals(s.replaceRange(2, 5, ""), s.removeRange(2, 5))
+        assertEquals(s.replaceRange(2..5, ""), s.removeRange(2..5))
     }
 
     test fun substringDelimited() {