- What is Nashorn?

Nashorn is a runtime environment for programs written in ECMAScript 5.1

that runs on top of JVM.

- How to find out more about ECMAScript 5.1?

The specification can be found at

    http://www.ecma-international.org/publications/standards/Ecma-262.htm

- How to checkout sources of Nashorn project?

Nashorn project uses Mercurial source code control system. You can

download Mercurial from http://mercurial.selenic.com/wiki/Download

Information about the forest extension can be found at

    http://mercurial.selenic.com/wiki/ForestExtension

and downlaoded using

    hg clone https://bitbucket.org/gxti/hgforest

You can clone Nashorn Mercurial forest using this command:

    hg fclone http://hg.openjdk.java.net/nashorn/jdk9 nashorn~jdk9

To update your copy of the forest (fwith the latest code:

    (cd nashorn~jdk9 ; hg fpull)

Or just the nashorn subdirectory with

    (cd nashorn~jdk9/nashorn ; hg pull -u)

To learn about Mercurial in detail, please visit http://hgbook.red-bean.com.

- How to build?

To build Nashorn, you need to install JDK 9. You may use the Nashorn

forest build (recommended) or down load from java.net.  You will need to

set JAVA_HOME environmental variable to point to your JDK installation

directory.

    cd nashorn~jdk9/nashorn/make

    ant clean; ant

- How to run?

Use the jjs script (see RELESE_README):

    cd nashorn~jdk9/nashorn

    sh bin/jjs <your .js file>

Nashorn supports javax.script API. It is possible to drop nashorn.jar in

class path and request for "nashorn" script engine from

javax.script.ScriptEngineManager. 

Look for samples under the directory test/src/jdk/nashorn/api/scripting/.

- Documentation

Comprehensive development documentation is found in the Nashorn JavaDoc. You can

build it using:

    cd nashorn~jdk9/nashorn/make

    ant javadoc

after which you can view the generated documentation at dist/javadoc/index.html.

- Running tests

Nashorn tests are TestNG based. Running tests requires downloading the

TestNG library and placing its jar file into the test/lib subdirectory. This is

done automatically when executing the "ant externals" command to get external

test suites (see below).

Once TestNG is properly installed, you can run the tests using:

    cd make

    ant clean test

You can also run the ECMA-262 test suite with Nashorn. In order to do

that, you will need to get a copy of it and put it in

test/script/external/test262 directory. A convenient way to do it is:

   git clone https://github.com/tc39/test262 test/script/external/test262

Alternatively, you can check it out elsewhere and make

test/script/external/test262 a symbolic link to that directory. After

you've done this, you can run the ECMA-262 tests using:

    cd nashorn~jdk9/nashorn/make

    ant test262

Ant target to get/update external test suites:

    ant externals

    ant update-externals

These tests take time, so we have a parallelized runner for them that

takes advantage of all processor cores on the computer:

    cd nashorn~jdk9/nashorn/make

    ant test262parallel

- How to write your own test?

Nashorn uses it's own simple test framework. Any .js file dropped under

nashorn/test directory is considered as a test. A test file can

optionally have .js.EXPECTED (foo.js.EXPECTED for foo.js) associated

with it. The .EXPECTED file, if exists, should contain the output

expected from compiling and/or running the test file.

The test runner crawls these directories for .js files and looks for

JTReg-style @foo comments to identify tests.

    * @test - A test is tagged with @test.

    * @test/fail - Tests that are supposed to fail (compiling, see @run/fail

      for runtime) are tagged with @test/fail.

    * @test/compile-error - Test expects compilation to fail, compares

      output.

    * @test/warning - Test expects compiler warnings, compares output.

    * @test/nocompare - Test expects to compile [and/or run?]

      successfully(may be warnings), does not compare output.

    * @subtest - denotes necessary file for a main test file; itself is not

      a test.

    * @run - A test that should be run is also tagged with @run (otherwise

      the test runner only compiles the test).

    * @run/fail - A test that should compile but fail with a runtime error.

    * @run/ignore-std-error - script may produce output on stderr, ignore

      this output.

    * @argument - pass an argument to script.

    * @option \ - pass option to engine, sample.

/**

 * @option --dump-ir-graph

 * @test

 */