Subj : Class width SpiderMonkey
To   : netscape.public.mozilla.jseng
From : "Jan Herling" <JanHerling@t-online.de>
Date : Wed Nov 05 2003 09:58 pm

Hallo all,

I have written the following C++ class for JavaSript with SpiderMonkey:

class ClassA
{
    double a;
    double b;
};

But this class works good with the following Script-File: (ca is an extern
def. var. from typ ClassA)

javascript:
ca.a = Math.random();

This only works because Mathe.random() proceeds a value between 0 and 1
(.4345 or .7644)
When I tryed the following Script-File, the program breaked down:

javascript:
ca.a = 0;      ("or ")     ca.a = 1;


Here is the important part of my Spidermonkey-Class:

JSBool ClassASetValue(JSContext *cx, JSObject *obj, double value)
{
    jsval val;
    JS_NewDoubleValue(cx, (jsdouble) value, &val);
    JS_SetProperty(cx, obj, "a", &val);
    ....
}


JSBool ClassAGetValue(JSContext *cx, JSObject *obj, float *value)
{
    jsval val;
    jsdouble jsd;
    .......
    JS_GetProperty(cx, obj, "a", &val);
    jsd = *JSVAL_TO_DOUBLE(val);                             ("or")
JS_ValueToNumber(cx, val, &jsd);        (makes no differents - allways
breaks down here if : "ca.a = 1" )
    *value = (float) jsd;
    .......
}

I think this is a problem with the conversion from JSVAL to DOUBLE.
Is this a well known problem or bug?
Or did I make a big mistake?

It would be nice, if someone of you could help me.

Jan

.