How to set correct fileName for exceptions thrown from a function in a Function object

[Tim Fox]

Hi Sundar,

I tried the sourceURL trick:

https://gist.github.com/purplefox/60619067006c3cc3eaee

But it doesn't seem to work. I suspect because the parsing of the eval 
fails before it gets to the last line (?) :(

I'm going to give a go with load()...

On 18/02/15 10:11, A. Sundararajan wrote:
> you can use
>
> 1) "load" from object - object with name and script properties.
>
> 2) or use 'eval' naming // #sourceURL comment
>
> as mentioned here:
>
> http://mail.openjdk.java.net/pipermail/nashorn-dev/2014-July/003174.html
>
> Can code for body of module function be something like 
> "eval(readScriptAsText() + "\n// #sourceURL=" + name)" ?
>
> Hope this helps,
> -Sundar
>
> On Wednesday 18 February 2015 03:30 PM, Tim Fox wrote:
>> I've added a simple reproducer that you can run in the repl:
>>
>> https://gist.github.com/purplefox/b03a2a6263c26e3206da
>>
>> Another observation is that line number is reported as 6, when it 
>> should be 5 (assuming the first line is line 1 which is normal 
>> convention afaik)
>>
>> On 18/02/15 09:40, Tim Fox wrote:
>>> Hi all,
>>>
>>> I'm currently using a CommonJS/npm modules require implementation 
>>> (npm-jvm) with Nashorn.
>>>
>>> Roughly, the way it works (and I'm sure you're already familiar with 
>>> this technique) is it takes the JavaScript module and wraps it in a 
>>> Function object:
>>>
>>> var body = readScriptAsText();
>>> var args   = ['exports', 'module', 'require', '__filename', 
>>> '__dirname'];
>>> var func = new Function(args, body);
>>> func.apply(module, [module.exports, module, module.require, 
>>> module.filename, dir]); // Execute it - this works fine
>>>
>>> Now let's say the actual module (foomodule.js) we are loading 
>>> contains this:
>>>
>>> module.exports = function() {
>>>     var num = 234;
>>>     num.substr(1, 1); // Will throw TypeError here
>>> }
>>>
>>> I.e. it simply exports a function, which will throw a TypeError when 
>>> it's executed.
>>>
>>> When the exported function is executed it does indeed throw a 
>>> TypeError:
>>>
>>> var f = require("foomodule");
>>>
>>> f(); // Throws TypeError
>>>
>>> Unfortunately the fileName field of the TypeError is set to 
>>> "<function>" not to "foomodule.js", which is unfriendly for the user.
>>>
>>> This is understandable as the Function object which wraps the module 
>>> doesn't know about "foomodule.js".
>>>
>>> So.. my question is.. how do I tell the Function object that the 
>>> "filename" it should use when exceptions are thrown from it is 
>>> "foomodule.js"?
>>>
>>> I have tried the following and none work:
>>>
>>> var func = new Function(args, body);
>>> func.name = "foomodule.js";
>>> func.fileName = "foomodule.js";
>>> func.displayName = "foomodule.js";
>>>
>>> Any insights would be greatly appreciated.
>>>
>>>
>>>
>>>
>>
>