Example

> eval("a = cos(0)")
 a =
        1
        0
> eval("a = sin(sqrt(2)/2)");
 a =
     0.65
> eval("b = tan(3);")
        0
> b
 b =
   -0.143
> printf( "Enter a function: " ); x = getline( "stdin" );
Enter a function: sqrt
> // this could be in a function
> eval("tmp = " + x.[1] + "(" + "3" + ")" );
 tmp =
     1.73
> printf( "Enter a function: " ); x = getline( "stdin" );
Enter a function: tanh
> eval("tmp = " + x.[1] + "(" + "3" + ")" );
 tmp =
    0.995