calculate an integral within a program

[ThomasA]

Hi,
I am working on a little program in optics.
One step is to evaluate an integral numerically and so I enthusiastically incorporated the int-command:
e.g. (simplified example, the real one is the representation of a Bessel function as an integral)
c := int(X^2,X,a,b);
I got an error message when compiling the code.
What is the reason for this 'result'?
Is it impossible to use higher commands like 'int' within a program (maybe because it is a CAS-command)?

Thomas