How do I get the function name from JSValue created with JS_NewCFunction2

[vincentparrett]

I am using JS_NewCFunction2, however elsewhere in the application (classdef.call ) I need to get the function name as provided to JS_NewCFunction2 from the JSValue - I cannot see any way to do this in quickjs.h?

[vincentparrett]

PS. I ted using JS_GetPropertyStr but it returns this

function name() {
    [native code]
}

So I tried calling that but it returned null.

[saghul]

Check build_backtrace I think we have some code to get the function name there.

[bnoordhuis]

JS_GetPropertyStr should work. If it doesn't, either you're doing something wrong (show full code in that case) or something monkey-patched the .name property.

[a-dato]

This seems to work:
var func := JS_NewCFunction(_ctx, @logme, 'alert', 1); var n := JS_GetPropertyStr(_ctx, func, 'name'); if JS_IsString(n) then var func_name := JS_ToCString(_ctx, n);

[vincentparrett]

That does work if I use the func immediately after creation - but in this case I am trying to get the name of the function inside the logme function (I should have mentioned that before) - it's a generic function I am using to implement IDispatch support.

I guess the this_val parameter to the C function is not actually the func object?

[a-dato]

We have this implemented in the Quickjs-rtti Delphi bridge (https://github.com/a-dato/quickJS-Rtti). There is a JSVariant type implemented in this file: QuickJS.Register.dn4d.intf.

[a-dato]

You should not use a generic function in this way. To get the integration going, you'll need to register your Delphi class with QuickJS (JS_NewClass) and then implement call back methods to provide information about your class to QuickJS (see JSClassDef).

Samples can be found in QuickJS.Register.impl: TJSRegister.InternalRegisterType
Also check method TJSRegister.get_own_property which handles all the calls from QuickJS into Delphi.

[vincentparrett]

@a-dato At this stage I am not working on exposing the delphi classes, I am working on IDispatch support so I can do this sort of thing (which I do with active scripting)

function foo() {
  var fs = new ActiveXObject('Scripting.FilysystemObject');
  var f = fs.CreateTextFile("c:\\testfile.txt", true);
}

I am using JSClassDef to create a wrapper for the IDispatch object and that is working.
FWIW, I chose to implement my own code rather than just use what you have done - mostly so that I can fully understand how it works.

[vincentparrett]

FWIW, I got past this, using a lookup table for the function names and passing the index through the magic parameter. I was just able to successfully run this script

function foo() {
  var fs = new ActiveXObject('Scripting.FilesystemObject');
  var a = fs.CreateTextFile("c:\\temp\\testfile.txt", true);
  a.WriteLine("This is a test.");
  a.Close();
}

Major progress!