The goal is to be able to create complex spells, that can manipulate the game's environment in non-preprogrammed ways, and to make the program understand spells. For example:

$@

$=Big
@=Fire

You can probably understand what this one means. The player types, writes, or selects symbols. Of course, a spell can be only a few characters, or more sophisticated spells could potentially be hundreds or thousands of symbols long.

How could something like this be accomplished?