Is it possible to use formulas indirectly based on text?

Let's say in the value of A1 = "SUM(2, 4)/2". I would like to put a formula in another cell which would evaluate this text with an "=" in the front.

Let's say the function I'm looking for is in A2. In this case the value in A2 is supposed to be 3, however if the value of A1 changes to "SUM(2, 4)/2+1" the value of A2 is supposed to change to 4.

I could do this with a macro but it would be more convenient if it was possible to do with a function.