Convert a string with mathematical expressions into a float

Question

A text field contains mathematical expressions like: 12+45-6 Is possible to convert this string to a number?

Can we use the predicate facility?

Answer 1

Yes, of course it's possible.

You should look into infix to postfix conversion using a stack: http://scriptasylum.com/tutorials/infix_postfix/algorithms/infix-postfix/index.htm

And then look into how to evaluate a postix expression, also using a stack: http://scriptasylum.com/tutorials/infix_postfix/algorithms/postfix-evaluation/index.htm