Unlike some other languages (like Perl), actionscript does not provide a function for parsing and executing arbitrary actionscript code. In other words, this does not work:
result = eval("2 * 3");
It *is* possible to write your own parser, but it requires a bit of work. For example, to convert the string "2 * 3" into separate symbols, you could use the split function.
str = "2 * 3";
symbols = str.split(' ');
Then you could walk thru the symbols, and examine what they are, and do the appropriate things. Writing parsers is not for the faint-hearted though.
It is somewhat easier if you use either prefix or postfix notation, such as like this: