Subj : Re: Can't get JS_CallFunction to work
To   : c.ibrahim
From : Brendan Eich
Date : Mon Oct 25 2004 12:17 pm

c.ibrahim wrote:

> Hi,
> 
> I saw a similar question posted like 3-4 months ago, but I cannot get
> much from the answer so I post this question again.
> 
> I need to use a function many a times so I decide to use
> JS_CompileFunction once and call the function many times using
> JS_CallFunction. I wanna make sure the idea works so I implement a
> simple test code, which to my dismay, does not work..
> 
> 
> the code snippet:
> 
> //somewhere in class constructor
> ...
> JSContext* m_context = JSNewContext(
> JSObject* m_global = JS_NewObject(
> 
> 
> //in class function that contains the simple test code
> ...
> long grade = -1;
> 
> //compile function
> const char* Grade = "function grade() { return 10 }";
> const char* filename = 0;
> uintN lineno = 0;
> JSFunction* func = JS_CompileFunction(m_context, m_global, "grade", 0,
> 0, Grade, strlen(Grade), filename, lineno);

You just compiled a function named "grade" whose body is the useless 
inner function declaration "function grade() { return 10 }".  That's the 
same as if you wrote it all in JS:

     function grade() {
         function grade() { return 10 }
     }

The outer function contains no return statement, so returns undefined.

Just pass the "return 10" body of the function to JS_CompileFunction as 
the "body" argument.

/be

.