Well barring the practice of specifying meaningful characters, the only thing I can come up with is to have your program use statistics to take it's best guess at what 'special' characters are. Let's say 95% of the characters are between 65 and 90, and every now and then there's a 44-32 pair. Then your program could be pretty sure that 44-32 is a delimiter, and that 65 and 90 are the ranges of characters used in keywords. (The above examples are ASCII).

However, that does nothing to eliminate words like 'in' and 'of' in a query, which you may want to do. It isn't very practical at all, I think, and you probably want to look at more practical ways to list possible delimiters, etc... Although the above could help you determine what charset you're using.