Re: Providing "script name" to eval

[A. Sundararajan]

Hi,

You can file name using ScriptEngine.FILENAME 
(http://docs.oracle.com/javase/8/docs/api/javax/script/ScriptEngine.html) property 
to associate script "file" name with a eval-ed script.

import javax.script.*;

public class Main {
  public static void main(String[] args) throws Exception {
      ScriptEngineManager m = new ScriptEngineManager();
      ScriptEngine e = m.getEngineByName("nashorn");
      e.put(ScriptEngine.FILENAME, "file.js");
      e.eval("foo");
  }
}

With that Nashorn will associate provided scriptName for that script. 
You can use "load" function as well to load a named script from a script 
object.

import javax.script.*;

public class Main {
  public static void main(String[] args) throws Exception {
      ScriptEngineManager m = new ScriptEngineManager();
      ScriptEngine e = m.getEngineByName("nashorn");
      e.put("scriptName", "file.js");
      e.put("script", "foo");
      e.eval("load({ script: script, name: scriptName })");
  }
}

 You can also use "eval naming" (See 
http://bugs.java.com/view_bug.do?bug_id=8032068) with jdk8u20+ and the 
example below:

import javax.script.*;

public class Main {
  public static void main(String[] args) throws Exception {
      ScriptEngineManager m = new ScriptEngineManager();
      ScriptEngine e = m.getEngineByName("nashorn");
      // older form of the directive //@ sourceURL works too.
      e.eval("//# sourceURL=myscript.js\nfoo");
  }
}

Hope this helps.
-Sundar

On Wednesday 09 July 2014 08:32 PM, Tim Fox wrote:
Hi folks,

I am using Nashorn to execute a piece of JavaScript using eval:

String str = loadFileFromClasspath(scriptName);

engine.eval(str);

If there's an error in the script, I get an error message something 
like this:

ReferenceError: "blah" is not defined in <eval> at line number 1245242

Is there any way informing the engine of the "script name" when 
running the eval so it provides nicer error messages like this:

ReferenceError: "blah" is not defined in myscript.js at line number 
1245242

Which is much nicer for the user.

(As a last resort I can catch any exceptions and replace <eval> with 
scriptName then rethrow them, but it would be nice if the engine could 
do this for me)