基于 JVM 的編程語言，Kotlin 1.0 Beta 3 發布

jopen 10年前發布 | 8K 次閱讀 Kotlin

Kotlin 是一個基于 JVM 的新的編程語言，由 JetBrains 開發。

其主要設計目標：

創建一種兼容Java的語言
讓它比Java更安全，能夠靜態檢測常見的陷阱。如：引用空指針
讓它比Java更簡潔，通過支持variable type inference，higher-order functions (closures)，extension functions，mixins and first-class delegation等實現。
讓它比最成熟的競爭對手Scala語言更加簡單。

Kotlin 1.0 Beta 3 發布，此版本主要是要完成標準庫開發，還有移除一些廢棄的語言結構。同時還有一些 bug 修復，性能提升。此版本包括庫，語言，IDE 和 Android 擴展方面的改進和修復。詳細改進內容請看發行說明。

改進列表：

increment deprecated in Progressions in favor of step property to Progressions, for-loops updated to refer to step
contains() and other similar extensions now accept supertypes of the element of the collection
Delegates.mapVal and mapVar, MapVal, MapVar, FixedMapVal, FixedMapVar are deprecated
String.toCharArray() introduced instead of String.getChars(); String.toCharList() deprecated
MutableCollection.removeAll(predicate: (T) -> Boolean) and similar for retainAll added
sequence(initialValueFunction, nextValueFunction) doesn't evaluate first value until it's requested by sequence iterator
sequenceOf(Progression) deprecated
flatten operation for Sequence<Iterable<...>> added

No references to PropertyMetadata are generated in the byte code
Suffixes to numeric literals, such as 1baz are prohibited
Comma-separated conditions in when without an argument are prohibited (KT-5143)
Annotation classes can't be instantiated (KT-4391)
Arrays of annotations supported as annotation arguments (KT-10136)
Generic types in catch clauses (including reified T) are prohibited (KT-9816)
protected members are allowed in companion objects
Calls to non-@JvmStatic protected members of companion objects from subclasses are marked as errors (unsupported)
"…" is reserved as a token (KT-9708)
Enum entry can not be used as a type (KT-5401)
Enum.values is deprecated in favor of Enum.values()
private setters are now deprecated for open properties
Local sealed classes are deprecated
Use of uninitialized variables in lambdas / object literals / local functions is forbidden
Overriding setter cannot weaken visibility
Inner classes are no longer allowed inside enum entries
Implicit receiver smart casts are supported
Older deprecations have become errors