官术网_书友最值得收藏!

The REPL

These days, most languages provide an interactive shell, and Kotlin is no exception. If you want to quickly write some code that you won't use again, then the REPL is a good tool to have. Some people prefer to test their methods quickly, but you should always write unit tests rather than using the REPL to validate that the output is correct.

Note: REPL is the common name when referring to an interactive shell, and is an abbreviation for read, evaluate, print, loop.

You can start the REPL by adding dependencies to the classpath in order to make them available within the instance. To look at an example, we will use the Joda library to deal with the date and time. First, we need to download the JAR. In a Terminal window, use the following commands:

$ wget https://github.com/JodaOrg/joda-time/releases/download/v2.9.4/joda-time-2.9.4-dist.tar.gz
$ tar xvf joda-time-2.9.4-dist.tar.gz

Now, you are ready to start the REPL. Attach the Joda library to its running instance, and import and use the classes it provides, as follows:

$ kotlinc-jvm -cp joda-time-2.9.4/joda-time-2.9.4.jar
Welcome to Kotlin version 1.1-M04 (JRE 1.8.0_66-internal-b17)
Type :help for help, :quit for quit
>>> import org.joda.time.DateTime
>>> DateTime.now()
2016-08-25T22:53:41.017+01:00

Running the preceding code will execute the now function of the DateTime class provided by the Joda library. The output is simply the current date and time.

主站蜘蛛池模板: 南丰县| 镇安县| 汤阴县| 共和县| 淳化县| 洪雅县| 勐海县| 城口县| 利津县| 瑞安市| 马边| 淄博市| 黔西县| 平昌县| 靖西县| 肇东市| 裕民县| 海阳市| 巴中市| 金平| 商洛市| 介休市| 昭觉县| 辽中县| 廉江市| 东乌珠穆沁旗| 大洼县| 万盛区| 二连浩特市| 资阳市| 延川县| 和静县| 通州市| 进贤县| 浮梁县| 阿城市| 岐山县| 兴隆县| 泰州市| 长岭县| 顺平县|