Telling if a value is a real number

Is there a way to tell if a value is a real number? I know about the <is input a number> block, but this returns TRUE even if a value is NaN or Infinity. I am making a graphing program and need to know if a value is one that is graphical. Thanks!

Two ideas: (1) There are only three weird real values: -INF, NaN, and INF. So just test for those. (2) If you load the infinite precision integer etc. library, you can

Just check if the imaginary part is 0.

No, he's not worried about complex numbers, just about infinity and NaN.

Thanks! I knew there was a way, but wasn't sure how.