Tonight I was working with a project that a buddy and I are doing on the side in an attempt to make money and I’m reviewing the code he’s got so far to make sure I have a good grasp on everything that’s going on. He’s built his own ColdFusion framework, and it appears pretty solid, if not a bit heavy. As I’m reviewing this code, however, I see that part of the routing code (yes, it’s an MVC framework) is using evaluate to dynamically execute methods. Although I see why this is happening, I’ve always assumed that evaluate was evil. My first thought was “Why isn’t he using CFINVOKE?”. My second thought was “But is that really better??”

Being the curious guy that I am I decided to make a very unscientific test where I would run two sets of code. The first set determines how much time it takes to create an object using createObject, then call a method against that object 100 times using evaluate. For example,

<cfset evaluate("someObject.#dynamicName#()") />

The second set determines how much time it takes to execute a method 100 times using just plain old CFINVOKE.

I ran each test 10 times with the following results:

• Evaluate: average of 267ms
• CFINVOKE: average of 284ms

The small margin of difference did catch me off guard, as I kind of expected CFINVOKE to perform badly, and evaluate to do much better, even though it is evil.

Then I thought, “How about we create the object, then create a reference to the method?” So something like this.

<cfset start = getTickCount() />
<cfset functionName = "test" />
<cfset o = createObject("MyObject").init() />
<cfset ptr = evaluate("l.o1.#functionName#") />
<cfloop from="1" to="100" index="l.i">
	<cfset ptr() />
</cfloop>

<cfset end = getTickCount() />

I ran this 10 times, and got an average of 15.5ms. WOAH!!! Big difference! So there ya go! Remember that ColdFusion is built on Java, and references are a powerful feature! Happy coding!