I am currently incorporating a scripting language into my engine, and after much research it seems LUA is the most appropriate in terms of platform compatibility and speed. After investigating, little has turned up as to whether a user will be able to edit LUA files within my iOS application in real-time.
The objective would be to have a single-line console input, to modify the environment, and then save back to file, ready to repeat the script on next load. I am cautious to advance, as I am unsure if the sandbox limitations over the I/O file systems would not allow this type of behavior.