Added LocalTime.Formats.ISO_BASIC (ISO 8601 basic format)

core/common/src/LocalTime.kt

@@ -197,6 +197,18 @@ public expect class LocalTime : Comparable<LocalTime> {
      * [kotlinx.datetime.format.DateTimeFormat] for [LocalTime] values.
      */
     public object Formats {
+        /**
+         * ISO 8601 basic format.
+         *
+         * Examples: `1234`, `123456`, `123456.789`, `123456.1234`.
+         *
+         * When formatting, seconds are always included, even if they are zero.
+         * Fractional parts of the second are included if non-zero.
+         *
+         * @sample kotlinx.datetime.test.samples.LocalTimeSamples.Formats.isoBasic
+         */
+        public val ISO_BASIC: DateTimeFormat<LocalTime>
+
         /**
          * ISO 8601 extended format.
          *

core/common/src/format/LocalTimeFormat.kt

@@ -279,6 +279,23 @@ internal class LocalTimeFormat(override val actualFormat: CachedFormatStructure<
 }
 
 // these are constants so that the formats are not recreated every time they are used
+internal val ISO_TIME_BASIC by lazy {
+    LocalTimeFormat.build {
+        char('T')
+        hour()
+        minute()
+        alternativeParsing({
+            // intentionally empty
+        }) {
+            second()
+            optional {
+                char('.')
+                secondFraction(1, 9)
+            }
+        }
+    }
+}
+
 internal val ISO_TIME by lazy {
     LocalTimeFormat.build {
         hour()

core/common/test/samples/LocalTimeSamples.kt

@@ -280,6 +280,20 @@ class LocalTimeSamples {
     }
 
     class Formats {
+        @Test
+        fun isoBasic() {
+            // Parsing and formatting LocalTime values using the ISO_BASIC format
+            val timeWithNanoseconds = LocalTime(hour = 8, minute = 30, second = 15, nanosecond = 160_000_000)
+            val timeWithSeconds = LocalTime(hour = 8, minute = 30, second = 15)
+            val timeWithoutSeconds = LocalTime(hour = 8, minute = 30)
+            check(LocalTime.Formats.ISO_BASIC.parse("T083015.16") == timeWithNanoseconds)
+            check(LocalTime.Formats.ISO_BASIC.parse("T083015") == timeWithSeconds)
+            check(LocalTime.Formats.ISO_BASIC.parse("T0830") == timeWithoutSeconds)
+            check(LocalTime.Formats.ISO_BASIC.format(timeWithNanoseconds) == "T083015.16")
+            check(LocalTime.Formats.ISO_BASIC.format(timeWithSeconds) == "T083015")
+            check(LocalTime.Formats.ISO_BASIC.format(timeWithoutSeconds) == "T083000")
+        }
+
         @Test
         fun iso() {
             // Parsing and formatting LocalTime values using the ISO format

core/commonKotlin/src/LocalTime.kt

@@ -84,6 +84,7 @@ public actual class LocalTime actual constructor(
     }
 
     public actual object Formats {
+        public actual val ISO_BASIC: DateTimeFormat<LocalTime> get() = ISO_TIME_BASIC
         public actual val ISO: DateTimeFormat<LocalTime> get() = ISO_TIME
     }
 

core/jvm/src/LocalTimeJvm.kt

@@ -88,6 +88,7 @@ public actual class LocalTime internal constructor(
     }
 
     public actual object Formats {
+        public actual val ISO_BASIC: DateTimeFormat<LocalTime> get() = ISO_TIME_BASIC
         public actual val ISO: DateTimeFormat<LocalTime> get() = ISO_TIME
 
     }