added count(predicate) helper function to String along with Char.is*() methods from java.lang.Character

libraries/stdlib/src/kotlin/Char.kt

@@ -0,0 +1,27 @@
+package kotlin
+
+public inline fun Char.isDefined(): Boolean = Character.isDefined(this)
+
+public inline fun Char.isDigit(): Boolean = Character.isDigit(this)
+
+public inline fun Char.isHighSurrogate(): Boolean = Character.isHighSurrogate(this)
+
+public inline fun Char.isIdentifierIgnorable(): Boolean = Character.isIdentifierIgnorable(this)
+
+public inline fun Char.isISOControl(): Boolean = Character.isISOControl(this)
+
+public inline fun Char.isJavaIdentifierPart(): Boolean = Character.isJavaIdentifierPart(this)
+
+public inline fun Char.isJavaIdentifierStart(): Boolean = Character.isJavaIdentifierStart(this)
+
+public inline fun Char.isJavaLetter(): Boolean = Character.isJavaLetter(this)
+
+public inline fun Char.isJavaLetterOrDigit(): Boolean = Character.isJavaLetterOrDigit(this)
+
+/**
+ * Returns true if the character is whitespace
+ *
+ * @includeFunctionBody ../../test/StringTest.kt count
+ */
+public inline fun Char.isWhitespace(): Boolean = Character.isWhitespace(this)
+

libraries/stdlib/src/kotlin/Strings.kt

@@ -211,4 +211,19 @@ public inline fun CharSequence.subSequence(start : Int, end : Int) : CharSequenc
 
 public inline fun CharSequence.get(start : Int, end : Int) : CharSequence? = subSequence(start, end)
 
-public inline fun CharSequence.toString() : String? = (this as java.lang.CharSequence).toString()
+public inline fun CharSequence.toString() : String? = (this as java.lang.CharSequence).toString()
+
+/**
+ * Counts the number of characters which match the given predicate
+ *
+ * @includeFunctionBody ../../test/StringTest.kt count
+ */
+public inline fun String.count(predicate: (Char) -> Boolean): Int {
+    var answer = 0
+    for (c in this) {
+        if (predicate(c)) {
+            answer++
+        }
+    }
+    return answer
+}

libraries/stdlib/test/StringTest.kt

@@ -3,17 +3,17 @@ package test.string
 import kotlin.io.*
 import kotlin.test.*
 
-import junit.framework.*
+import org.junit.Test as test
 
-class StringTest() : TestCase() {
+class StringTest {
-    fun testStringIterator() {
+    test fun stringIterator() {
         var sum = 0
         for(c in "239")
             sum += (c.toInt() - '0'.toInt())
         assertTrue(sum == 14)
     }
 
-    fun testStringBuilderIterator() {
+    test fun stringBuilderIterator() {
         var sum = 0
         val sb = StringBuilder()
         for(c in "239")
@@ -26,7 +26,7 @@ class StringTest() : TestCase() {
         assertTrue(sum == 14)
     }
 
-    fun testOrEmpty() {
+    test fun orEmpty() {
         val s: String? = "hey"
         val ns: String? = null
 
@@ -34,16 +34,22 @@ class StringTest() : TestCase() {
         assertEquals("", ns.orEmpty())
     }
 
-    fun testToShort() {
+    test fun toShort() {
         assertEquals(77.toShort(), "77".toShort())
     }
 
-    fun testToInt() {
+    test fun toInt() {
         assertEquals(77, "77".toInt())
     }
 
-    fun testToLong() {
+    test fun toLong() {
         assertEquals(77.toLong(), "77".toLong())
     }
 
+    test fun count() {
+        val text = "hello there\tfoo\nbar"
+        val whitespaceCount = text.count { it.isWhitespace() }
+        assertEquals(3, whitespaceCount)
+    }
+
 }