Question

Take an xml like this:

<?xml version="1.0"?>
<events>
    <event>
        <start></start>
        <duration></duration>
        <begin>{somecallback}</begin>
        <complete>{someclass.someproperty = somevalue;}</complete>
    </event>
</events>

• I need to be able to parse the xml and execute the string versions of javascript code. I know javascript has an eval function, but I need to know if eval can act on the above begin and complete or if there is an easier way to do this.

Both begin and complete need to either directly access a callback (without parameters), or directly set a value to a property belonging to a class. I’m sure I can eval() a callback, but I am unsure how to proceed with directly setting property values in this manner.

Answer 1

eval will operate on objects that are in scope as expected:

js> var o = {}
js> eval('o.p = 1')
1
js> o.p
1

What you should consider is if you need the flexibility of eval for what you are doing. Can somecallback be a property of an object? If so, you can call o[fn]() where fn is “somecallback,” for instance. This is much safer than using eval. Your <complete> section is too vague for me to recommend a way to avoid eval in the second case however.