Ruby evaluate without eval?

Question

How could I evaluate at mathematical string without using eval?

Example:

mathstring = \"3+3\"

Anyway that can be evaluated without

Answer 1

You must either or eval it, or parse it; and since you don't want to eval:

mathstring = '3+3'
i, op, j = mathstring.scan(/(\d+)([+\-*\/])(\d+)/)[0] #=> ["3", "+", "3"]
i.to_i.send op, j.to_i #=> 6

If you want to implement more complex stuff you could use RubyParser (as @LBg wrote here - you could look at other answers too)