Cheap and Easy Dynamic Method Calling in CFScript

November 25, 2008 · 8 Comment s

For reasons I cannot entirely explain, I was trying to call dynamic methods in a cfc in cfscript. (The cfc code was calling a method within itself) I tested a few syntactically wrong ways of getting it done. It the underlying fact that functions are another type of variable in ColdFusion hit me. I should be able to assign dynamic variable to a new variable, and call that as a function. It worked.

function test(input){
return input;
}

functionName = "test";

args.input = "Yo!";

tempfunc = variables[functionName];

output = tempfunc(argumentCollection = args);

writeOutput(output);

</cfscript>

I feel like someone must have done this before, but could find nothing on it. So I figured I would blog it.

Tags: ColdFusion

8 response s so far ↓

1 Ben Nadel // Nov 25, 2008 at 10:12 AM

Looks good. I wish that we could do something like this:

variables[ functionName ]();

This works at a "functional" level (as it is what you are essentially doing); but, this fails to compile due to parsing issues.
2 Terrence Ryan // Nov 25, 2008 at 10:17 AM

I agree, Ben, as that method would also work with method calls on other objects too.
3 Sean Corfield // Nov 25, 2008 at 10:37 AM

I think you'll find that if you do this with CFC methods, the called function doesn't correctly bind to VARIABLES or THIS scope...
4 Henry Ho // Nov 25, 2008 at 11:23 AM

@Sean, so this method doesn't really work for calling CFC methods?
5 Terrence Ryan // Nov 25, 2008 at 11:24 AM

Do you mean intra-cfc or external to that CFC?

I know it doesn't work externally. but it does work intra-cfc. I assume as the variables and this scope are same for the dynamic call.
6 Mark Mandel // Nov 25, 2008 at 1:17 PM

@Terrence, yeah, you are fine intra-cfc. I do this all the time when I don't want to escape out of a cfscript block to use cfinvoke.

Either that or when I pass a function to a function, as otherwise, for some reason cf throws a wobbly if you try and call arguments.foo(argumentCollection=args);
7 Joshua Curtiss // Dec 16, 2008 at 12:04 PM

Perfect. This is perfect timing. I needed this for a Transfer decorator using onMissingMethod(), and it works great. Thanks!!!
8 Aaron Neff // Jan 6, 2010 at 2:29 AM

"variables[functionName]();"

+1

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