I love the idea of image-based languages, and lately I've been toying with Common Lisp via sbcl. I've read in a few places about how through being able to save and load back an image of the virtual machine, you can evolve an application or set of apps running on that image.

I get how to load code into an image and get it running, slime makes this sort of thing very nice, but my question is this: How can I tell what functions are defined in an image? Let's say I want to make an update to a function days or months after it has been running and I can't remember the name. Is there any way to get to the code or even just the names of the functions defined in an the image?

Now, I do write the code out into source and load it in via the repl, so I have a copy there, but it seems like this would be an obvious feature.